Answer:
it is directly proportional to the temperature of the gas
Explanation:
PLEASE HELP
MY PARENTS WILL KILL ME IF I DONT GET MY SCHOOL WORK DONE BY 12 PM TODAY!! AND I DONT UNDERSTAND IT!!
If the mass of an unknown object is 2 grams and the volume is 2.35 cubic centimeters, what is the density of that object?
a. _________________________
b. Look back at Table 4.1. Based on your calculated density, what is the substance? _________________________
Answer:
oh ok
Explanation:
what is the purpose of sand bath in preparation of ethane
Answer:
The sand bath spreads the heat out so that the flask is heated evenly. This reduces the chance of the flask breaking and ensures that there are no hot spots in the reaction mixture which could lead to excessive charring,
Explanation:
The image shown here is a good illustration of which law?
Answer:
The answer is A.Newton's First law
Which gas is described incorrectly in the passage?
(The answer choices are the capitalized words)
Gases such as carbon dioxide, nitrogen, and oxygen are constantly recycled in the atmosphere through different processes. For example, plants absorb CARBON DIOXIDE and releases OXYGEN during photosynthesis. On the other hand, plants and animals both take in oxygen and release CARBON DIOXIDE is removed from the atmosphere by the process of rock weathering.
Answer:
Nice
Explanation:
An aqueous solution of sodium chloride, NaCl has a mol fraction of 0.15. calculat the molality of NaCl
Answer:
8.8mol/l
Explanation:
but I'm not percent sure.
You are boiling water to cook some noodles. You notice bubbles forming on the bottom of the pot. Your brother thinks it is a chemical change. Is he correct?
Yes. The bubbles contain hydrogen and oxygen that separated from the water.
Yes. The bubbles are now filled with air.
No. The water changes into carbon dioxide.
No. It is a physical change when water is heated and is converted into water vapor.
Answer:
i think its Yes. The bubbles contain hydrogen and oxygen that separated from the water but i could be wrong so i would just wait to see if anybody else says anything
Explanation:
Describe the patterns and atomic mass is an ion charges in the periodic table
Answer:
The atomic number increases across a period and down the group or family. The atomic mass generally increases with atomic number with a few exceptions.
john roller skates with a constant speed of 8 miles per hour. how long will he take to travel a distance of 28 miles? please use the formula Speed = Distance/Time
Answer:
3.5hrs
Explanation:
Using the formula Speed = Distance/Time
Given
Speed = 8mi/hr
Distance = 28miles
Get the time
Time = Distance/Speed
Time = 28/8
Tme = 3.5hrs
Hence it will take 3.5hrs to travel
Mixing hydrochloric acid and sodium hydroxide is an example of an exothermic
reaction. This means...
Select one
energy is taken in during the chemical reaction
hydrochloric acid and sodium hydroxide are the products of the reaction
Energy released during the chemical reaction
There is no change in energy during the chemical reaction
Answer:
exothermic means that energy was released during the chemical reaction
Explanation:
For the following reaction, 29.9 grams of sulfur dioxide are allowed to react with 6.26 grams of oxygen gas . sulfur dioxide(g) + oxygen(g) sulfur trioxide(g) What is the maximum mass of sulfur trioxide that can be formed? grams What is the FORMULA for the limiting reagent? What mass of the excess reagent remains after the reaction is complete? grams
Answer: a) The maximum mass of sulfur trioxide that can be formed is 31.4 grams
b) The FORMULA for the limiting reagent is [tex]O_2[/tex]
c) Mass of excess reagent remains is 4.8 grams
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} SO_2=\frac{29.9g}{64g/mol}=0.467moles[/tex]
[tex]\text{Moles of} O_2=\frac{6.26g}{32g/mol}=0.196moles[/tex]
[tex]2SO_2(g)+O_2(g)\rightarrow 2SO_3(g)[/tex]
According to stoichiometry :
1 mole of [tex]O_2[/tex] require = 2 moles of [tex]SO_2[/tex]
Thus 0.196 moles of [tex]O_2[/tex] will require=[tex]\frac{2}{1}\times 0.196=0.392moles[/tex] of [tex]SO_2[/tex]
Thus [tex]O_2[/tex] is the limiting reagent as it limits the formation of product and [tex]SO_2[/tex] is the excess reagent as (0.467-0.392) = 0.075 moles or [tex]0.075mol\times 64g/mol=4.8g[/tex] are left.
As 1 mole of [tex]O_2[/tex] give = 2 moles of [tex]SO_3[/tex]
Thus 0.196 moles of [tex]O_2[/tex] give =[tex]\frac{2}{1}\times 0.196=0.392moles[/tex] of [tex]SO_3[/tex]
Mass of [tex]SO_3=moles\times {\text {Molar mass}}=0.392moles\times 80g/mol=31.4g[/tex]
Thus 31.4 g of [tex]SO_3[/tex] will be produced from the given masses of both reactants.
When Aluminum oxide is heated with iron no reaction takes place?
Answer:
Explanation:
That's correct. Once Aluminum becomes an ion, it is very hard to force it to take back its electrons. Only a few elements can do it. Iron is not one of them.
According to the quantum-mechanical model for the hydrogen atom, which electron transition produces light with the longer wavelength: 3p + 2s or 4p + 3p? Match the words in the left column to the appropriate blanks in the sentences on the right. Reset Help increases As the n level increases, the energy and thus the levels are each 3p → 2s other. Therefore, the transition would have a greater energy difference than the transition from inversely decreases Energy and wavelength are proportional, so the transition would farther from produce a longer wavelength. 4p + 3p directly closer to
Answer:
Explanation:
The main task here is that there are some missing gaps in the above question that needs to be filled with the appropriate answers. So, we are just going to do rewrite the answer below as we indicate the missing gaps by underlining them and making them in bold format.
SO; In the quantum-mechanical model of the hydrogen atom.
As the n level increases. the energy increases and thus levels are closer to each other. Therefore, the transition 3p→2s would have a greater energy difference than the transition from 4p→3p.
[tex]Energy \ and \ wavelength \ are \ inversely \ proportional , \ so \ the \ \mathbf{ 4p\to 3p} \ transition \ would[/tex][tex]produce \ a \ longer \ wavelength.[/tex]
Should vaccinations be required for students to attend public school?
Answer:
I don't think so for now, there hasn't been much research done with the vaccine and children so we really don't know how children's bodies will react to it. Once more studies are done with the vaccine and children and is proven safe then yes, kids should use it in order to attend public school.
A 50.0 mL solution of 0.129 M KOH is titrated with 0.258 M HCl. Calculate the pH of the solution after the addition of each of the given amounts of HCl.
A) 0.00ml
B)7.00ml
C)12.5ml
D)18.0ml
E)24.0ml
F)25.0ml
G)26.0ml
H)29.0ml
please show work with steps .
Answer:
A- pH = 13.12
B- pH = 12.91
C- pH = 12.71
D- pH = 12.43
E- pH = 11.55
F- pH = 7
G- pH = 2.46
H- pH = 1.88
Explanation:
This is a titration of a strong base with a strong acid. The neutralization reaction is: KOH (aq) + HCl (aq) → H₂O(l) + KCl(aq)
Our pH at the equivalence point is 7, because we have made a neutral salt.
To determine the volume at that point we state the formula for titration:
mmoles of base = mmoles of acid
Volume of base . M of base = Volume of acid . M of acid
50mL . 0.129M = 0.258 M . Volume of acid
Volume of acid = (50mL . 0.129M) / 0.258 M → 25 mL (Point F)
When we add 25 mL of HCl, our pH will be 7.
A- At 0 mL of acid, we only have base.
KOH → K⁺ + OH⁻
[OH⁻] = 0.129 M
To make more easy the operations we will use, mmol.
mol . 1000 = mmoles → mmoles / mL = M
- log 0.129 = 0.889
14 - 0.889 = 13.12
B- In this case we are adding, (7 mL . 0.258M) = 1.81 mmoles of H⁺
Initially we have 0.129 M . 50 mL = 6.45 mmoles of OH⁻
1.81 mmoles of H⁺ will neutralize, the 6.45 mmoles of OH⁻ so:
6.45 mmol - 1.81 = 4.64 mmoles of OH⁻
This mmoles of OH⁻ are not at 50 mL anymore, because our volume has changed. (Now, we have 50 mL of base + 7 mL of acid) = 57 mL of total volume.
[OH⁻] = 4.64 mmoles / 57 mL = 0.0815 M
- log 0.0815 M = 1.09 → pOH
pH = 14 - pOH → 14 - 1.09 = 12.91
C- In this case we add (12.5 mL . 0.258M) = 3.22 mmoles of H⁺
Our initial mmoles of OH⁻ would not change through all the titration.
Then 6.45 mmoles of OH⁻ are neutralized by 3.22 mmoles of H⁺.
6.45 mmoles of OH⁻ - 3.22 mmoles of H⁺ = 3.23 mmoles of OH⁻
Total volume is: 50 mL of base + 12.5 mL = 62.5 mL
[OH⁻] = 3.23 mmol / 62.5 mL = 0.0517 M
- log 0.0517 = 1.29 → pOH
14 - 1.11 = 12.71
D- We add (18 mL . 0.258M) = 4.64 mmoles of H⁺
6.45 mmoles of OH⁻ are neutralized by 4.64 mmoles of H⁺.
6.45 mmoles of OH⁻ - 4.64 mmoles of H⁺ = 1.81 mmoles of OH⁻
Total volume is: 50 mL of base + 18 mL = 68 mL
[OH⁻] = 1.81 mmol / 68 mL = 0.0265 M
- log 0.0265 = 1.57 → pOH
14 - 1.57 = 12.43
E- We add (24 mL . 0.258M) = 6.19 mmoles of H⁺
6.45 mmoles of OH⁻ are neutralized by 6.19 mmoles of H⁺.
6.45 mmoles of OH⁻ - 6.19 mmoles of H⁺ = 0.26 mmoles of OH⁻
Total volume is: 50 mL of base + 24 mL = 74 mL
[OH⁻] = 0.26 mmol / 74 mL = 3.51×10⁻³ M
- log 3.51×10⁻³ = 2.45 → pOH
14 - 2.45 = 11.55
F- This the equivalence point.
mmoles of OH⁻ = mmoles of H⁺
We add (25 mL . 0.258M) = 6.45 mmoles of H⁺
All the OH⁻ are neutralized.
OH⁻ + H⁺ ⇄ H₂O Kw
[OH⁻] = √1×10⁻¹⁴ → 1×10⁻⁷ → pOH = 7
pH → 14 - 7 = 7
G- In this case we have an excess of H⁻
We add (26 mL . 0.258M ) = 6.71 mmoles of H⁺
We neutralized all the OH⁻ but some H⁺ remain after the equilibrium
6.71 mmoles of H⁺ - 6.45 mmoles of OH⁻ = 0.26 mmoles of H⁺
[H⁺] = 0.26 mmol / Total volume
Total volume is: 50 mL + 26 mL → 76 mL
[H⁺] = 0.26 mmol / 76 mL → 3.42×10⁻³ M
- log 3.42×10⁻³ = 2.46 → pH
H- Now we add (29 mL . 0.258M) = 7.48 mmoles of H⁺
We neutralized all the OH⁻ but some H⁺ remain after the equilibrium
7.48 mmoles of H⁺ - 6.45 mmoles of OH⁻ = 1.03 mmoles of protons
Total volume is 50 mL + 29 mL = 79 mL
[H⁺] = 1.03 mmol / 79 mL → 0.0130 M
- log 0.0130 = 1.88 → pH
After equivalence point, pH will be totally acid, because we always have an excess of protons. Before the equivalence point, pH is basic, because we still have OH⁻ and these hydroxides, will be neutralized through the titration, as we add acid.
The pH value is given by 14 less the logarithm of the hydronium ion
concentration or the hydrogen ion concentration in the solution.
Responses (approximate values):
The pH values are;
A) 13.11
B) 12.91
C) 12.71
D) 12.42
E) 11.54
F) 7
G) 2.469
H) 1.884
Which is used to find the pH of the solution?A) Concentration of the KOH = 0.129 M
Amount of HCl added = 0.00 ml
The pH = -log[H⁺] = 14 - pOH
pOH = -log[OH⁻]
Which gives;
pH = 14 - (-log[OH⁻] )
pH = 14 - (-log(0.129)) ≈ 13.11B) Volume of acid added = 7.00 mL = 0.007 L
Concentration of the acid = 0.258 M HCl
Number of moles of acid, H⁺ = 0.007 × 0.258 moles = 0.001806 moles
Number of moles of KOH remaining, OH⁻= 0.05 × 0.129 - 0.001806 = 0.004644
Number of moles of OH⁻ = 0.004644 moles
[tex]Concentration, \ [OH^-] = \dfrac{0.004644 \, moles}{0.05 7 \, L} \approx \mathbf{ 0.0815 \, M}[/tex]
pH of solution = 14 - (-log(0.0815)) ≈ 12.91C) 12.5 mL HCl contains, 0.0125 × 0.258 moles = 0.003225 moles
OH⁻ remaining = 0.05 × 0.129 - 0.003225 = 0.003225 moles
[tex]Concentration \ of \ [OH^-]= \dfrac{0.003225\, moles}{(0.05 + 0.0125) \, L} = \mathbf{0.0516 \, M}[/tex]
pH of solution = 14 - (-log(0.0516)) ≈ 12.71D) 18.0 mL HCl contains, 0.018 × 0.258 moles = 0.004644 moles
OH⁻ remaining = 0.05 × 0.129 - 0.004644 = 0.001806 moles
[tex]Concentration \ of \ [OH^-] = \dfrac{0.001806\, moles}{(0.05 + 0.018) \, L} \approx \mathbf{0.0266\, M}[/tex]
pH of solution = 14 - (-log(0.0266)) ≈ 12.42E) 24.0 mL HCl contains, 0.024 × 0.258 moles = 0.006192 moles
OH⁻ ion remaining = 0.05 × 0.129 - 0.006192 = 0.000258 moles
[tex]Concentration \ of \ [OH^-] = \dfrac{0.000258\, moles}{(0.05 + 0.024) \, L} \approx \mathbf{0.0035\, M}[/tex]
pH of solution = 14 - (-log(0.0035)) ≈ 11.54F) 25.0 mL HCl contains, 0.025 × 0.258 moles = 0.00645 moles
[OH⁻] remaining = 0.05 × 0.129 - 0.00645 = 0 moles
[tex]Concentration \ of \ [OH^-] = \dfrac{0\, moles}{(0.05 + 0.024) \, L} \approx 0\, M[/tex]
Therefore;
Number of moles of KOH = 0, or the solution is neutralized
[OH⁻] = [H⁺]
Which gives;
pH = pOH = 7G) 26.0 mL HCl contains, 0.026 × 0.258 moles = 0.006708 moles
[OH⁻] remaining = 0.05 × 0.129 - 0.006708 = -0.000258 moles
Therefore
Number of moles of H⁺ = 0.000258
[tex]\mathbf{Concentration} \ of \ \mathbf{[H^+] }= \dfrac{0.000258\, moles}{(0.05 + 0.026) \, L} \approx 0.003395\, M[/tex]
pH of solution = (-log(0.003395)) ≈ 2.469H) 29.0 mL HCl contains, 0.029 × 0.258 moles = 0.007482 moles
H⁺ remaining = 0.007482 - 0.05 × 0.129 = 0.001032 moles
Therefore
Number of moles of H⁺ = 0.001032
[tex]Concentration \ of \ [H^+] = \mathbf{ \dfrac{0.001032\, moles}{(0.05 + 0.029) \, L}} \approx 0.01306\, M[/tex]
pH of solution = (-log(0.01306)) ≈ 1.884Learn more about the pH of a solution here:
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A closed, nonreactive system contains species Aand Bin vapor/liquid equilibrium. Species Ais a very light gas, essentially insoluble in the liquid phase. The vapor phase contains both species Aand B. Some additional moles of species Bare added to the system, which is then restored to its initial T and P. As a result of the process, does the total number of moles of liquidincrease, decrease, or remain unchanged?
Answer:
Remain unchanged.
Explanation:
The total number of moles of liquid remain unchanged as the some moles of species B are added to the system because specie B that is added in the liquid phase is again restored after addition. If the specie B did not restored after addition to the liquid phase so the total number of moles increases in the liquid phase so that's why we can say that the liquid phase remain unchanged.
Given that blood exerts the same osmotic pressure as a 0.15 M NaCl solution, which solution could be the hypertonic solution?/search?
a. 0.68 M NaCl solution
b. 0.15 M NaCl solution
c. 0.008 M NaCl solution
Answer:
a. 0.68 M NaCl solution
Explanation:
The tonicity of a solution can either be hypotonic, hypertonic and isotonic. Hypertonic solution is a solution which possesses a higher concentration of solute in relation to another solution.
According to this question, a solution is said to contain 0.15 M NaCl solute. This means that a solution that will be hypertonic to this solution will have a much more concentration of solute, which based on the options provided is the 0.68 M NaCl solution.
This is the chemical formula for the compound calcium chloride: CaCl2
In this compound, how many atoms are combined?
O1
02
O3
O4
Answer:
3
Explanation:
1 Calcium atom and two chlorine atoms
what mass, in grams, of CO2 and H20 N
is formed from 2.55 mol of propane?
Answer: The mass of [tex]CO_2[/tex] and [tex]H_2O[/tex] produced are 336.6 g and 183.6 g respectively.
Explanation:
The combustion reaction between propane and oxygen leads to formation of carbon dioxide and water.
Law of Conservation of mass states that the mass will remain constant for a balanced equation. This is carried out when the total number of atoms on reactant side is same as the total number of atoms on the product side. Thus the equation must be balanced.
[tex]C_3H_8+5O_2\rightarrow 3CO_2+4H_2O[/tex]
a) 1 mol of propane produces = 3 moles of [tex]CO_2[/tex]
Thus 2.55 mol of propane produces = [tex]\frac{3}{1}\times 2.55=7.65 moles of [tex]CO_2[/tex]
mass of [tex]CO_2=moles\times {\text {molar mass}}=7.65mol\times 44g/mol=336.6g[/tex]
b) 1 mol of propane produces = 4 moles of [tex]H_2O[/tex]
Thus 2.55 mol of propane produces = [tex]\frac{4}{1}\times 2.55=10.2 moles of [tex]H_2O[/tex]
mass of [tex]H_2O=moles\times {\text {molar mass}}=10.2mol\times 18g/mol=183.6g[/tex]
The mass of [tex]CO_2[/tex] and [tex]H_2O[/tex] produced are 336.6 g and 183.6 g respectively.
Complete the following table. The first row has been completed as an example.
Symbol
Atomic number Mass number Number of protons Number of neutrons
17C1
17
37
17
20
238
U
92
92
238
146
92
325
16
32
16
16
5 Fe
54
26
I
19
1.K
41
22
Submit Answer
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4 item attempts remaining
Answer:
because all chemical reaction involve the rearrangement of atoms, the mass is an electron is negatively charged, it has a mass approximately 1/2000 that of a, Atoms of an element that contain the same number of protons but a different Copy and complete the following tables concerning the isotopes of silicon SI-28.
Explanation:
HELP!!! TIMED! THANK YOU!
Answer:
The answer is A.
Explanation:
Answer:
Explanation:
I believe it is a
What type of element has 8 electrons in their outer most level?
non-metals
metals
noble gases
alkali metals
Answer:
Noble gases
Explanation:
Neon and argon have 8 electrons in their outermost shells. The elements which have 8 electrons in the outermost shell or in the valence shell,are known as the noble gases.
It's the third one or Noble gases.
A Period 2 element has the following successive ionization energies. Identify the element...
1st: 1087 kJ/mol
2nd: 2353 kJ/mol
3rd: 4621 kJ/mol
4th: 6223 kJ/mol
5th: 37832 kJ/mol
6th: 47279 kJ/mol
7th: 55261 kJ/mol
8th: 69875 kJ/mol
Answer:
9th:08473 kJ/mol
Explanation:
HAHAHAHAHAHAHAHAHAHA
Scientists Believe that:
A. The continents are shifting
B. The world was once one big mass
C. The center of the earth is made of iron and nickel
D. All of the above
E. None of the above
Answer: D
Explanation: Today, we know that the continents rest on massive slabs of rock called tectonic plates. They are constantly in movement and they are responsible for several natural disasters. Approximetly 335 million years ago, during the late Paleozoic and early Mesozoic eras, the world was one big mass, called Pangea, which eventually would start to break apart about 175 million years ago. At the center of the Earth is the core, which has two parts. The solid, inner core of iron has a radius of about 760 miles (about 1,220 km), according to NASA. It is surrounded by a liquid, outer core composed of a nickel-iron alloy.
I hope it helps
Answer:
the answer is D
Explanation:
How many zinc atoms are contained in 3.75 moles of zinc?
2.26 × 10²⁴ atoms Zn
General Formulas and Concepts:Math
Pre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to RightChemistry
Atomic Structure
Reading a Periodic TableAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Stoichiometry
Using Dimensional AnalysisExplanation:Step 1: Define
3.75 mol Zn (Zinc)
Step 2: Identify Conversions
Avogadro's Number
Step 3: Convert
[DA] Set up: [tex]\displaystyle 3.75 \ mol \ Zn(\frac{6.022 \cdot 10^{23} \ atoms \ Zn}{1 \ mol \ Zn})[/tex][DA] Multiply/Divide [Cancel out units]: [tex]\displaystyle 2.25825 \cdot 10^{24} \ atoms \ Zn[/tex]Step 4: Check
Follow sig fig rules and round. We are given 3 sig figs.
2.25825 × 10²⁴ atoms Zn ≈ 2.26 × 10²⁴ atoms Zn
Determine whether each practice is recommended to keep a micropipette clean and functioning properly.
1. Use a new tip any time you change solutions.
A. Recommended.
B. Not recommended.
2. Turn the micropipette upside down after loading with liquid.
A. Recommended.
B. Not recommended.
3. Save tips after removal to reuse them later.
A. Recommended.
B. Not recommended.
4. Place the micropipette on a rack after using it.
A. Recommended.
B. Not recommended.
5. Place the micropipette on the bench between uses.
A. Recommended.
B. Not recommended.
Answer:
1. A
2. B
3. B
4. A
5. B
Explanation:
1. Recommended. That way cross-contamination is prevented.
2. Not recommended. The inner mechanism of the micropipette should not come in contact with any liquid whatsoever.
3. Not recommended. It contradicts statement 1.
4. Recommended. That way the micropipette remains completely vertical, minimizing the risks of being decalibrated.
5. Not recommended. If it lays on the bench it will be horizontal, thus contradicting statement 4.
Answer:
1. A
2. B
3. B
4. A
5. B
Explanation:
What are the three types of plate boundaries? What is the direction of movement at each boundary?
There are three kinds of plate tectonic boundaries: divergent, convergent, and transform plate boundaries.
This image shows the three main types of plate boundaries: divergent, convergent, and transform.
This image shows the three main types of plate boundaries: divergent, convergent, and transform. Image courtesy of the U.S. Geological Survey. Download image (jpg, 76 KB).
The Earth’s lithosphere, which includes the crust and upper mantle, is made up of a series of pieces, or tectonic plates, that move slowly over time.
A divergent boundary occurs when two tectonic plates move away from each other. Along these boundaries, earthquakes are common and magma (molten rock) rises from the Earth’s mantle to the surface, solidifying to create new oceanic crust. The Mid-Atlantic Ridge and Pacific Ring of Fire are two examples of divergent plate boundaries.
When two plates come together, it is known as a convergent boundary. The impact of the colliding plates can cause the edges of one or both plates to buckle up into a mountain ranges or one of the plates may bend down into a deep seafloor trench. A chain of volcanoes often forms parallel to convergent plate boundaries and powerful earthquakes are common along these boundaries.
At convergent plate boundaries, oceanic crust is often forced down into the mantle where it begins to melt. Magma rises into and through the other plate, solidifying into granite, the rock that makes up the continents. Thus, at convergent boundaries, continental crust is created and oceanic crust is destroyed.
Two plates sliding past each other forms a transform plate boundary. One of the most famous transform plate boundaries occurs at the San Andreas fault zone, which extends underwater. Natural or human-made structures that cross a transform boundary are offset—split into pieces and carried in opposite directions. Rocks that line the boundary are pulverized as the plates grind along, creating a linear fault valley or undersea canyon. Earthquakes are common along these faults. In contrast to convergent and divergent boundaries, crust is cracked and broken at transform margins, but is not created or destroyed.
How many
neutrons would
be found in
carbon-15 if it
were to exist?
Show your work.
Answer:
8 neutrons
A is the number of neutrons plus protons in the nucleus. However, we already know that there are 7 protons. Therefore, there must be 8 neutrons in the nucleus to add up to 15. Table 3.
Element Symbol Number of Neutrons
carbon 146C 8
nitrogen 147N 7
157N 8
oxygen 168O 8
Explanation:
15 g NiO is dissolved into enough water to make 800. mL of solution. What is the molar concentration of the solution? Report your answer with the correct number of significant figures.
Answer: 0.25
Explanation: M = moles of solute / volume of solution (L)
First, you need to calculate the number of moles using the given mass and the molar mass.
15 g74.692 g/mol≈0.20 mol
Then, you can solve for molarity using the molarity equation. The answer should be reported to two significant figures.
M=0.20 mol/ 0.800 L = 0.25 M
The molar concentration of NiO solution is 0.251 M.
What is molar concentration?Molar concentration is defined as a measure by which concentration of chemical substances present in a solution are determined. It is defined in particular reference to solute concentration in a solution . Most commonly used unit for molar concentration is moles/liter.
The molar concentration depends on change in volume of the solution which is mainly due to thermal expansion. Molar concentration is calculated by the formula, molar concentration=mass/ molar mass ×1/volume of solution in liters.
In terms of moles, it's formula is given as molar concentration= number of moles /volume of solution in liters.Considering the given example, molar concentration of NiO is found out as follows,
molar concentration=15/74.69 ×1/0.8= 0.251 M.
where 74.69 is molar mass of NiO.
Thus, the molar concentration of NiO is 0.251 M.
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i don’t understand this please help!!!
Answer:
Numbers after atoms are subscripts. Numbers before atoms are coefficients.
Equation: 2Na +Cl2 -> 2NaCl
Given: 6.8 grams of Na
Unknown: moles of NaCl
Set up: [tex]6.8g Na *\frac{1 mole Na}{22.99 g Na}*\frac{2 moles NaCl}{2 moles Na} =.2957 moles NaCl[/tex]
Explanation:
We know that the reactants are Na and Cl and that what is being produced, the products, is NaCl.
Na + Cl -> NaCl
CAREFUL! Cl is a diatomic ion, is it gets a subscript of 2! This means there need to be 2 cl atoms on the right side as well. But now there are 2 Na on the right side. So we multiply Na by 2 on the left so that both sides have two Na atoms.
2Na +Cl2 -> 2NaCl
B)
We know that there are 6.8 grams of Na. This is our given.
What do we want to find out? We want to find how many moles of NaCl there are, so that is our unknown.
C) A mole ratio is exactly what it sounds like. From our balanced equation, we can see that there are 2 moles of Na and 2 moles of NaCl. In other words, there are 2 moles of Na for every 2 moles Nacl. In notation, this is [tex]\frac{2 mole Na}{2 Mole NaCl}[/tex] or 2:2. You can simplify to 1:1 ratio, but as equations get more complex I find it easier to not. It depends on what your teacher wants and what you find easier.
D)
By set up I assume they mean stoichiometry (chemistry conversion) . First I'm going to split up the set up so that it is easier to understand.
We start with the given and convert that into moles Na. We can do this by remembering that there are 22.99 grams for every 1 mole Na:
6.8 g Na* [tex]\frac{1 mole Na}{22.99g Na} = .2957 moles Na[/tex]
Now we can use that mole ration we found in part C to convert moles of Na into moles of NaCl:
[tex].2957 moles Na *\frac{2 moles NaCl}{2 moles Na}= .2957[/tex]
Usually, we will put these together to get
[tex]6.8g Na *\frac{1 mole Na}{22.99 g Na}*\frac{2 moles NaCl}{2 moles Na} =.2957 moles NaCl[/tex]
Tip: in Stoichiometry, it is important to remember that your units should cancel out until you only have the units you want. If there are moles of Na in the numerator, there should be moles of Na in the denominator of the following fraction. If there are grams Na in the numerator, there should be grams Na in the denominator and so and so on until you are only left with the unit you want, which, in this case, is moles of NaCl.
For keyboard navigation, use the up/down arrow keys to select an answer. a) Because the positive charge is on primary and secondary allylic carbocations etc. b) Because the positive charge is on a primary and a tertiary carbon c) Because the positive charge is on a primary and a secondary carbon d) Because the positive charge is on a secondary and a tertiary carbon
Answer:
b) because the positive charge is on primary and a tertiary carbon
Explanation:
The allylic carbon atom carries positive charge when primary carbon has positive charge. It forms an ion with tertiary carbon atom to form resonance. In secondary carbocation the positive charge is on secondary carbon atom. The atom are attracted and electrons form carbon - carbon sigma.
