Answer: 16.21
Explanation:
A student measures the length of two pieces of paper as 8.21 in and 8.0 in. the total length is 16.21 with 4 significant figures.
What are significant figures?
The significant figures or digits are the form of scientific methd which represent the digit from zero to nine and use when the value is uncertain where starting zeros are not significant and decimal is also not a significant figure.
In the given value the total is 16.21 with 4 significant figures with it has 4 significant digits and the decimal with it is not significant after adding from which the respective value is here.
Therefore, with 4 significant figures where the student measures the length of two pieces of paper as 8.21 in and 8.0 in. the total length is 16.21.
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A 6.0 M HCI solution is diluted to make 500 mL of a 2.5 M HCI solution. What volume of the 6.0 M HCI solution is required to make this solution?
Answer:
V₁ = 208.3 mL
Explanation:
Given data:
Initial molarity of HCl = 6.0 M
Final volume = 500 mL
Final molarity = 2.5 M
Volume of initial solution required = ?
Solution:
Formula:
M₁V₁ = M₂V₂
Now we will put the values in formula.
6.0 M × V₁ = 2.5 M ×500 mL
6.0 M × V₁ = 1250 M.mL
V₁ = 1250 M.mL / 6.0 M
V₁ = 208.3 mL
sodium hydroxide is extremely soluble in water. a saturated solution contains 678.57 grams of sodium hydroxide 1.00 liter of solution. calculate the molarity of a saturated sodium hydroxide solution.
Answer:
M = 17 M
Explanation:
Given data:
Mass of sodium hydroxide = 678.57 g
Volume of solution = 1.00 L
Molarity of solution = ?
Solution:
Molarity is used to describe the concentration of solution. It tells how many moles are dissolve in per litter of solution.
Formula:
Molarity = number of moles of solute / L of solution
Number of moles of sodium hydroxide:
Number of moles = mass/molar mass
Number of moles = 678.57 g /40 g/mol
Number of moles = 17 mol
Molarity:
M = 17 mol/1.00 L
M = 17 mol/L
M = 17 M
How many grams of CO2 are produced from 10 grams of C2H6
Answer:
Explanation:
no of moles of C2H6=10/30=0.33
complete combustion of 2 moles of ethane produce 4 moles of CO2 therefore 0.33 moles of C2H6 produced 0.66 moles of CO2
now moles =given mass/molar mass
mass= moles*molar mass
mass of CO2=0.67*44=29.48 g
Graphite is sometimes used to reduce the friction between
two surfaces that are rubbing together.
Explain how it does this.
Graphite is sometimes used to reduce the friction between two surfaces that are rubbing together. Therefore, this happen because of weak covalent bond.
What is graphite?Graphite is among the most prevalent carbon allotropes. It is also the stable allotrope for carbon, and as such, it is employed in electrochemistry to define the heat of synthesis of carbon compounds. With a hardness of 2.09-2.23 g/cm3, graphite is an excellent conductor of electricity and heat.
Graphite is a large covalent structure in which each carbon atom is covalently linked to three other carbon atoms. Graphite is sometimes used to reduce the friction between two surfaces that are rubbing together. This happen because of weak covalent bond.
Therefore, graphite is sometimes used to reduce the friction between two surfaces that are rubbing together. This happen because of weak covalent bond.
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Q4. The student started with 16.0 grams of NaCl, show the calculation for the percent error that
represents the amount of salt lost during the separation of the mixture.
Answer:
72.6% Error
Explanation:
% error = [tex]\frac{Real-Measured}{Real} * 100[/tex]
[tex]\frac{58.44-16}{58.44} *100= 72.6[/tex]
58.44 is the weight of NaCl
18. A pure substance in the form of a mystery powder in the lab could not be
separated by any physical changes. However, when this pure substance is put over
a flame, a chemical change takes place forming a gas of carbon dioxide along with
a different looking powder. Based on this evidence, which type of matter is most
likely the pure substance?
Answer:a compound
Explanation:
PLS HURRY
What methods are you using to test this (or each) hypothesis?
Answer:
Fair test.
PLS GIVE BRAINLIEST
HURRY PLEASE HELP
Four students are discussing the benefits and problems associated with using nuclear energy as alternative energy source. Which student has the strongest argument about using nuclear energy?
A. Nuclear power plants pollute the environment and causes cancer in populations that use nuclear energy instead of traditional electricity.
B. Nuclear power plants provide more energy than traditional coal plants; however, nuclear power plants also produce more greenhouse gases.
C. Nuclear power plants run a high risk of nuclear meltdown killing all the organisms in a 20 mile radius.
D. Nuclear power plants provide more energy than traditional coal plants and these plants do not produce greenhouse gases.
Answer:
A
Explanation:
its A
facts o.o
Nuclear power plants pollute the environment and causes cancer in populations that use nuclear energy instead of traditional electricity. Hence option A is correct.
What is nuclear power plant?Nuclear power plant is defined as a particular kind of power plant that produces electricity by nuclear fission. Nuclear power plants use the heat generated by nuclear fission to transform water into steam in a controlled environment, which then powers generators to produce electricity. Low-enriched uranium fuel is used in nuclear power plants to generate electricity through a process known as fission, which involves breaking uranium atoms in a nuclear reactor.
A clean energy source with no emissions is nuclear. It produces energy by fission, which is the splitting of uranium atoms to release energy. Without the toxic consequences that come from burning fossil fuels, electricity is produced using the heat from fission to produce steam, which turns a turbine.
Thus, nuclear power plants pollute the environment and causes cancer in populations that use nuclear energy instead of traditional electricity. Hence option A is correct.
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Why aren't the masses on the periodic table whole numbers?
How many valence electrons are there is the molecule CH 06P2
How many mL (to the nearest mL) of 0.140-M KF solution should be added to 400. mL of 0.212-M HF to prepare a pH
Answer:
205mL of 0.140M KF solution
Explanation:
pH = 2.70 solution.
It is possible to obtain the pH of the buffer of HF-KF using the H-H equation:
pH = pKa + log [KF] / [HF]
Where pH is desire pH = 2.70
pKa is pKa of HF = 3.17
[KF] could be taken as moles of KF
And [HF] moles of HF: 400.0mL = 0.4L * (0.212mol/L) = 0.0848 moles of HF
Replacing:
2.70 = 3.17 + log [KF] / [0.0848 moles HF]
-0.47 = log [KF] / [0.0848 moles HF]
0.3388 = [KF] / [0.0848 moles HF]
[KF] = 0.02873 moles of KF must be added.
In mL using concentration of KF (0.140M):
0.02873 moles KF * (1L / 0.140 mol) = 0.205L =
205mL of 0.140M KF solutionWhich statement accurate describes plate tectonics?
Answer:
the lithosphere is broken into sections called plates.
Answer:
The lithosphere is broken into sections called plates.
Explanation:
edge2020
PLEASE HELPPP!!!
A few weeks ago you make ice cubes in the freezer using ice cube trays. Today when you go to get some to chill your refreshing beverage, you notice the ice cubes have seem to have shrunk because they do not fill their compartments. What process would explain why the ice is smaller? *
1 point
condensation
melting
sublimation
because there ice is melting....... is your answer
How many moles is 3.01 x 10 24 molecules of oxygen ( g)?
Answer:
5.00 moles O₂
General Formulas and Concepts:
Chemistry - Atomic Structure
Using Dimensional AnalysisAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Explanation:
Step 1: Define
3.01 × 10²⁴ molecules O₂
Step 2: Convert
[tex]3.01 \cdot 10^{24} \ mc \ O_2(\frac{1 \ mol \ O_2}{6.022 \cdot 10^{23} \ mc \ O_2} )[/tex] = 4.99834 moles O₂
Step 3: Check
We are given 3 sig figs. Follow sig fig rules and round.
4.99834 moles O₂ ≈ 5.00 moles O₂
A train travels 245 km in 6.25 hours. What is the speed of the train?
Group of answer choices
53.2 km/hr
1531.25 km/hr
39.2 m/h
39.2 km/hr
Answer:
D
Explanation:
My favorite pancake recipe
2 cups all purpose | plain flour, (290 g | 10 oz)
1/4 cup granulated sugar or sweetener, (60g | 2 oz)
4 teaspoons baking powder
1/4 teaspoon baking soda
1/2 teaspoon salt
1 3/4 cups milk, (440ml)
1/4 cup butter, (60g | 2 oz)
2 teaspoons pure vanilla extract
1 large egg
Combine everything in a bowl (separate wet and dry) and cook at medium low heat until it is brown and there are bubbles on top. Then serve with syrup. Good luck!!!
The molarity of a solution of 6
.0 g of KCl in 80. mL of solution is ________
Answer:
Question are not clear
Answer:
0.075 mol/dm^3
Explanation:
Is pencil lead a conductor or insulator?
Answer:
Conductor
Explanation:
What we call “pencil lead” is actually a substance called graphite, which consists of many stacked sheets of carbon atoms. Like a metal, graphite is conductive and therefore can act like a wire on paper to create the circuit.
Please help. Will give brainliest.
Answer:
B.
Explanation:
i think its B
When forming ions, nitrogen will gain or lose how many electrons, forming a cations or anions with a what charge?
Answer:
Nonmetals form negative ions (anions). A nitrogen atom must gain three electrons to have the same number of electrons as an atom of the following noble gas, neon. Thus, a nitrogen atom will form an anion with three more electrons than protons and a charge of 3−.
Explanation:
have advanced
6. Even when matter goes through a physical or chemical change the matter cannot be ____ or ___.
Write the correct name for each compound. a. N2O5 b. Si2F4 c. S3F d. OF2 e. H4P6 f. C2O4 g. HF3
Could you please help I am struggling with this
Answer:
a. Boron trifluoride
b. Propane
c. Dinitrogen pentoxide
d. Carbon Dioxide
e. Silicon Octafluroride?
Explanation:
Glad to help :)
A solution has a concentration of 0.001 M NaOH (MM = 40.00
g/mol). Suppose you have 1000 g of this solution which
occupies a volume of 1 L. What is the percent by mass
concentration of NaOH?
Percent by mass : 4.10⁺³%
Further explanationThe concentration of a solution can be expressed in units such as molarity, normality, mass percent, volume percent etc.
[tex]\tt \%mass=\dfrac{mass~solute}{mass~solution}\times 100\%[/tex]
mass solute= mass of NaOH
mass of NaOH :
[tex]\tt 0.001~mol/L\times 1~L\times 40~g/mol=0.04~g[/tex]
mass solution = 1000 g
% mass :
[tex]\tt \dfrac{0.04}{1000}\times 100=4.10^{-3}\%[/tex]
The percent by mass concentration of NaOH in the given solution is approximately 0.004%.
To calculate the percent by mass concentration of NaOH, we must find the mass of NaOH in solution.
First, we determine how many moles of NaOH are present in the solution:
Molarity (M) is calculated as moles of solute per liter of solution.
1 L = 0.001 M = mole of NaOH
We rearrange the equation to find that one mole of NaOH is equal to 0.001 moles.
Mass of NaOH = moles of NaOH * molar mass of NaOH
Mass of NaOH = 0.001 mol * 40.00 g/mol
Mass of NaOH = 0.04 g
The mass of the solution is 1000 g which is given in the question.
Percent by mass concentration of NaOH = (mass of NaOH / mass of solution) * 100%
Percent by mass concentration of NaOH = (0.04 g / 1000 g) * 100%
Percent by mass concentration of NaOH = 0.004%
Hence, the percent by mass concentration of NaOH in the given solution is approximately 0.004%.
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calculate the number of oxygen atoms and its mass in 50g of CaCo3
The number of oxygen atoms = 3
Mass = 24 g
Further explanationThe formula of a compound shows the composition of the constituent elements
CaCO₃ is composed of 3 types of elements, namely Ca, C and O
The amounts of each of these elements in the compound CaCO₃:
Ca = 1 C = 1 O = 3So the number of oxygen atoms = 3
mass of Oxygen :
[tex]\tt mass~O=\dfrac{3\times Ar~O}{MW~CaCO_3}\times mass~CaCO_3\\\\mass~O=\dfrac{3\times 16}{100}\times 50=24~g[/tex]
what makes an element the same as another element
Answer:elements cannot be split into two
Explanation:elements are pure substances which cannot be split into two by chemical means
True or False: Scientists use what they know about the properties of different molecules to separate mixtures. *
Answer:
True
Explanation:
Mixtures are substances with indefinite composition. They consist of two or more elements and or compounds in any proportion by mass.
Their constituents retain their identities i.e. physical properties are retained. Their constituents reacts differently to changed conditions. They can easily be separated into constituents by physical methods.From these properties we can clearly identify that to separate mixtures, we use the differences in the chemical properties of the constituents of the mixtures.
5. Psilocybin is made of C 50.70%, H 6.03%, N 9.86%, 22.51%, P 10.90%. a. Find the empirical formula.
The empirical formula : C₁₂H₁₇N₂O₄P
Further explanationThe empirical formula is the smallest comparison of atoms of compound =mole ratio of the components
The principle of determining empirical formula
Determine the mass ratio of the constituent elements of the compound. Determine the mole ratio by by dividing the percentage by the atomic massC
[tex]\tt \dfrac{50.7}{12}=4.225[/tex]
H[tex]\tt \dfrac{6.03}{1}=6.03[/tex]
N[tex]\tt \dfrac{9.86}{14}=0.704[/tex]
O[tex]\tt \dfrac{22.51}{16}=1.407[/tex]
P[tex]\tt \dfrac{10.9}{31}=0.352[/tex]
Divide by the smallest mole ratio(0.352)
C : H : N : O : P
[tex]\tt C\rightarrow \dfrac{4.225}{0.352}=12[/tex]
[tex]\tt H\rightarrow \dfrac{6.03}{0.352}=17[/tex]
[tex]\tt N\rightarrow \dfrac{0.704}{0.352}=2[/tex]
[tex]\tt O\rightarrow \dfrac{1.407}{0.352}=4[/tex]
[tex]\tt P\rightarrow \dfrac{0.352}{0.352}=1[/tex]
pls help!!
The number that represents a neutral pH is ________.
Answer:
7
Explanation:
A sled is at rest at the top of a slope 2 m high. The sled has a mass of 45 kg. What is the sleds potential energy
Answer:
[tex]\boxed {\boxed {\sf882 \ Joules}}[/tex]
Explanation:
Potential energy can be found by multiplying the mass by the height by the gravitational acceleration.
[tex]PE=mgh[/tex]
The mass is 45 kilograms. The height is 2 meters. The gravitational acceleration on Earth is 9.8 meters per seconds squared.
[tex]m=45 \ kg \\h= 2 \ m \\g=9.8 \ m/s^2[/tex]
Substitute the values into the formula.
[tex]PE=45 \ kg * 2 \ m * 9.8 m/s^2[/tex]
Multiply.
[tex]PE=441 kg*m/s^2*2 \ m[/tex]
[tex]PE= 882 \ kg *m/s^2 *m[/tex]
1 kg*m/s^² is equal to 1 Newton (N). Substitute N in for kg*m/s²
[tex]PE=882 \ N*m[/tex]
1 Newton meter (N*m) is equal to 1 Joule (J). Our current answer is equivalent to 882 Joules.
[tex]PE= 882 \ J[/tex]
The sled's potential energy is 882 Joules.
Answer:
882 J
Explanation:
Diagram shows that both gases occupy the same volume under the same conditions of temperature and pressure. Show a numerical set up for how you will calculate the new volume of the gas, if the pressure remains constant ( at 1.2atm), but the temperature is raised from 293k to 398K.
Answer:
1.70 L
Explanation:
From the question given above, the following data were obtained:
Pressure (P) = constant = 1.2 atm
Initial volume (V1) = 1.25 L
Initial temperature (T1) = 293 K
Final temperature (T2) = 398 K
Final volume (V2) =?
Since the pressure is constant, the gas is obeying Charles' law. Thus, we can obtain the new volume (V2) of the gas by applying the Charles' equation as shown below:
V1/T1 = V2/T2
1.25 / 293 = V2 /398
Cross multiply
293 × V2 = 1.25 × 398
293 × V2 = 497.5
Divide both side by 293
V2 = 497.5 / 293
V2 = 1.70 L
Therefore, the new volume of the gas is 1.70 L.
Q2. A 0.696 mol sample of Cu is added to 146 mL of 5.5 M HNO3. Assuming the following
reaction is only one that occurs;
Cus) + HNO3(aq) → Cu(NO3)2(aq) + H2O() + NO()
Will the Cu react completely? What is the limiting reagent and what is the remaining compound
in mass?
Explanation:
Given parameters:
Number of moles of Cu = 0.696mol
Volume of HNO₃ = 146mL
Concentration of HNO₃ = 5.5M
Unknown:
Will Cu react completely = ?
Limiting reagent = ?
Remaining mass of the compound = ?
Solution:
The equation of the reaction is given as;
Cu + 4HNO₃ → Cu(NO₃)₂ + 2H₂O + 2NO₂
Let us find the number of moles of HNO₃ ;
Number of moles = concentration x volume
Number of moles = 5.5 x 146 x 10⁻³L = 0.803mol
From the balanced reaction equation;
1 mole of Cu reacted with 4 mole of HNO₃
0.696 mole of Cu will require 4 x 0.696 = 2.784mole of HNO₃
So, the limiting reactant is HNO₃ because it is in short supply.
Cu will completely react
Mass of the remaining compound we need;
mass = number of moles x molar mass
Number of moles = 2.784 - 0.803 = 1.981mole
So, mass = 1.981 x (1 + 14 + 3(16)) = 124.81g of HNO₃ is required to make the reaction complete.
The limiting reagent is HNO3 and the remaining compound in mass is 25.1 grams of Cu.
The reaction taking place in the given case is,
Based on the given information,
• The moles of Cu given is 0.696 moles.
• The volume of HNO3 given is 146 ml and the molarity of HNO3 is 5.5 M.
Now the moles of HNO3 can be determined as,
[tex]Moles = \frac{M1V1}{1000} \\Moles = \frac{5.5M*146 ml}{1000} \\Moles = 0.803 moles[/tex]
• In order to find the limiting reagent, there is a need to divide moles by their stoichiometric coefficient, that is,
Cu = 0.696/3 = 0.232 moles and HNO3 = 0.803/8 = 0.100 moles
• As the moles of HNO3 is present in less amount, therefore, HNO3 will be the limiting reagent.
Now the remaining copper left in the reaction will be,
[tex]= 0.696-\frac{3}{8} *0.803\\= 0.696-0.300\\= 0.396 moles[/tex]
Now the mass of remaining copper will be = Moles * Molecular mass of Cu
[tex]Mass = 0.396 moles * 63.5 g/mol\\Mass = 25.1 g[/tex]
Thus, the mass of remaining compound is 25.1 grams and the limiting reagent is HNO3.
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