Answer:
Dmitri Mendeleev
Explanation:
He was a Russian Scientist who decided to reorganize the periodic table after other notable scientists such as Antoine-Laurent Lavoisier had also tried to organize it based on the states of matter of the elements.
Mendeleev reorganized the period in the order of increasing atomic mass although there were some other modifications by modern scientists.
Someone please help me with the second question ONLY
Answer:
no
Explanation:
this experiment could not be replicated, because there are no specific measurements. the details would not be the same because it does not include the type of paper used nor the diameter, width or length. A guess of the measurements would be the only way to replicate this experiment but other then that, no you cannot.
WILL MARK BRAINLIEST IF GOOD EXPLANATION...
Ethyl acetate is a sweet-smelling solvent used in varnishes and fingernail polish remover. It is produced industrially by heating acetic acid and ethanol
together in the presence of sulfuric acid, which is added to speed up the
reaction. The ethyl acetate is distilled off as it is formed. The equation for the
process is as follows.
CH3COOH + CH3CH2OH --> CH3COOCH2CH3 + H2O
Determine the percentage yield in the following cases:
a. 68.3 g of ethyl acetate should be produced but only 43.9 g is recovered.
b. 0.0419 mol of ethyl acetate is produced but 0.0722 mol is expected. (Hint:
Percentage yield can also be calculated by dividing the actual yield in moles
by the theoretical yield in moles.)
c. 4.29 mol of ethanol is reacted with excess acetic acid, but only 2.98 mol of
ethyl acetate is produced.
d. A mixture of 0.58 mol ethanol and 0.82 mol acetic acid is reacted and 0.46
mol ethyl acetate is produced. (Hint: What is the limiting reactant?)
Answer:
a) 64.27%
b) 58%
c) ethanol is the limiting reactant
d) ethanol is the limiting reactant
Explanation:
We have to note that the expected yield is the theoretical yield while the actual mass or amount of product formed is the actual yield.
a) theoretical yield=68.3g
Actual yield= 43.9 g
Percentage yield= 43.9/68.3 ×100
Percentage yield= 64.27%
b) theoretical yield= 0.0722 moles
Actual yield = 0.0419
Percentage yield= 0.0419/0.0722 × 100
Percentage yield= 58%
c) note that the limiting reactant yields the least number of moles of product
Ethanol will be the limiting reactant since it is not present in excess.
d) from the reaction equation;
1 mole of acetic acid produces 1 mole of ethyl acetate
0.58 moles of ethanol produces 0.58 moles of ethyl acetate
1 mole of acetic acid yields 1 mole of ethyl acetate
Hence 0.82 moles of acetic acid yields 0.82 moles of ethyl acetate
Hence ethanol is the limiting reactant.
PLZZZZZZZZ HELLLLLLLLLLLLLLLLLPPPPPP!!!!! soo stuckkkkk
Formamide decomposes at high temperature. If 0.186 mol of formamide (HCONH2) dissociates in a 2.16 L flask at 400 K, what are the concentrations of all species present at equilibrium at 400 K? (hint: calculate concentrations first) (b) What is the total pressure in the container at equilibrium?
Answer:
a) [COHNH₂] = 0.001 mol/L, [NH₃] = [CO] = 0.085 mol/L
b) 5.59 atm
Explanation:
a) The decomposition reaction of formamide is the following:
COHNH₂(d) ⇆ NH₃(g) + CO(g)
The equilibrium constant of the reaction above is:
[tex]K_{c} = \frac{[NH_{3}][CO]}{[COHNH_{2}]} = 4.84 (400 K)[/tex]
The initial concentration of formamide is:
[tex] C_{COHNH_{2}} = \frac{\eta}{V} = \frac{0.186 moles}{2.16 L} = 0.086 mol/L [/tex]
Where: η is the number of moles and V is the volume
Now, in the equilibrium the concentration of all species is:
COHNH₂(d) ⇆ NH₃(g) + CO(g)
0.086 - x x x
[tex] K_{c} = \frac{[NH_{3}][CO]}{[COHNH_{2}]} = \frac{x*x}{0.086 - x} [/tex]
[tex] 4.84*(0.086 - x) -x^{2} = 0 [/tex]
By solving the above equation for x we have:
x = 0.085 mol/L = [NH₃] = [CO]
[COHNH₂] = 0.086 - 0.085 = 0.001 mol/L
Therefore, the concentrations of all species present at equilibrium at 400 K is [NH₃] = [CO] = 0.085 mol/L and [COHNH₂] = 0.001 mol/L.
b) To find the total pressure in the container we need to find first the constant Kp as follows:
[tex] K_{p} = K_{c}*RT^{\Delta n} [/tex]
Where R is the gas constant = 0.082 Latm/(Kmol), T is the temperature = 400 K and Δn = 1
[tex] K_{p} = K_{c}*RT^{\Delta n} = 4.84*(0.082*400)^{1} = 158.8 [/tex]
Now, the total pressure is:
[tex] p_{T} = p_{COHNH_{2}} + p_{NH_{3}} + p_{CO} [/tex]
The pressure of COHNH₂ can be found using Ideal Gas Law:
[tex] P = \frac{nRT}{V} = \frac{0.186 moles*0.082 L*atm/(K*mol)*400 K}{2.16 L} = 2.82 atm [/tex]
Using the equilibrium constant we can find the pressure of NH₃ and CO:
COHNH₂(d) ⇆ NH₃(g) + CO(g)
2.82 - x x x
[tex] K_{p} = \frac{P_{NH_{3}}*P_{CO}}{P_{COHNH_{2}}} [/tex]
[tex] 158.8*(2.82 - x) - x^{2} = 0 [/tex]
By solving the above equation for x we have:
[tex] x = P_{NH_{3}} = P_{CO} = 2.77 atm [/tex]
[tex] P_{COHNH_{2}} = 2.82 - 2.77 = 0.05 atm [/tex]
Thus, the total pressure is:
[tex] p_{T} = p_{COHNH_{2}} + p_{NH_{3}} + p_{CO} = (0.05 + 2.77 + 2.77) atm = 5.59 atm [/tex]
Hence, the total pressure in the container at equilibrium is 5.59 atm.
I hope it helps you!
What is the molarity of a solution that contains 6 moles of NaCl in 3 L of solution?
a
2.0 M
b
0.5 M
c
0.25 M
d
18.0 M
Answer:
a
2.0 M
Explanation:
divide 6by 3
formula : molarity=moles divided by volume of solutions
MY ELEMENT IS SODIUM
1. Summarize the physical and chemical properties of the element you selected.
2. In the lesson, many models were used to depict the atom. How did these models help you understand atomic structure?
3. How do protons, neutrons, and electrons differ in terms of their electrical charges and locations within the atom?
4. Describe the four fundamental forces. Which of these forces are involved in chemical bonding?
Please answer these questions or at least one.
Answer:
Explanation:
1. The element you selected is Sodium. some of the physical properties are
i. Sodium has a strong metallic lustre
ii. Sodium are usually silver white in color
iii. Sodium is soft it can be cut with knife
iv. Sodium are malleable and ductile.
v. Sodium conduct electricity
Sodium belong to group 1 elements which are called Alkali metals. Sodium have one valency electron and it gives this electron easily during bonding . This is one reason sodium and other alkali metals are very reactive. Sodium can instantly be oxidized by water. Sodium has a relative atomic mass of approximately 23 amu.
2. There are various models that describe atoms .This models includes John Dalton models, J.J Thompson model, Ernest Rutherford model, Bohr's models etc. This models made us understand the role and location of each sub atomic particles. The models shed more light on subatomic particles like electron which revolve around the nucleus. It provide more information on what contribute to the weight of an atom.
3. The proton , neutron and electron are subatomic particles of an atom. The proton and the neutron are located at the nucleus of an atom. The proton and neutron contributes majorly to the weight of an atom. The proton is positively charge while neutron has no charge.
Electron is found to move around the nucleus in cloud. The electron is negatively charge. The electron determines bonding of atoms. An atom is electrically neutral if the number of proton is equal to the number of electron.
4. The four fundamental forces includes weak nuclear forces , strong nuclear forces , gravity and electromagnetic forces.
Weak nuclear forces is responsible for particle decay .Nuclear forces don't play a role in chemical reaction . If they are involve in a reaction it becomes nuclear reaction not chemical reaction.
Strong nuclear forces causes a strong nuclear interaction and it is the strongest among the 4 fundamental forces. This strong force only operate when subatomic particles are much closer to each other.
Gravity force is too weak to affect chemical reaction much. The gravity forces involves the interaction between two objects with energy and mass.
The electromagnetic force act between charged particles like negatively charged electron and positively charged proton. Electromagnetic force is the most important force in chemical bonding as it depends on the arrangement of atoms and the state of their electron. Electromagnetic forces exist in various forms like the covalent bond, metallic, ionic , dipole dipole, hydrogen bonds and many more. The major force involve in chemical bonding is the electromagnetic force.
Using a broom to clean sidewalks and driveways is a way to reduce water pollution.
Answer: Yes
Explanation:
Answer:
trueeeeee
Explanation:
Which is the electron configuration for bromine?
Answer:
first answer
Explanation:
atomic number of bromine is 35
[tex]1{s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{2} 3 {p}^{6} 3 {d}^{10} 4 {s}^{2} 4 {p}^{5} [/tex]
Answer:
1s22s22p63s23p64s23d104p5
Explanation:
;)
When naming acids, the term “hydro” is used then there are or are not (pick the correct one) any oxygens.
Answer:
There are no oxygen
Explanation:
Hydro is used when naming hydrogen compound and oxo is used when naming oxygen compound
How many moles of sodium hydroxide would react with 1 Mole of sulphuric acid?
Answer:
Two moles.
Explanation:
Sulphuric (sulfuric) acid [tex]\rm H_2SO_4[/tex] is a diprotic acid. When one mole of [tex]\rm H_2SO_4[/tex] molecules dissolve in water, two moles of [tex]\rm H^{+}[/tex] ions would be produced.
[tex]\rm H_2SO_4 \to 2\, H^{+} + {SO_4}^{2-}[/tex].
On the other hand, sodium hydroxide [tex]\rm NaOH[/tex] is a monoprotic base. When one mole of [tex]\rm NaOH[/tex] formula units dissolve in water, only one mole of hydroxide ions [tex]\rm OH^{-}[/tex] would be produced.
[tex]\rm NaOH \to Na^{+} + OH^{-}[/tex].
Note that [tex]\rm H^{+}[/tex] and [tex]\rm OH^{-}[/tex] react at a one-to-one ratio:
[tex]\rm H^{+} + OH^{-} \to H_2O[/tex].
As a result, it would take [tex]2\; \rm mol[/tex] of [tex]\rm OH^{-}[/tex] to react with the [tex]\rm 2\; mol[/tex] of [tex]\rm H^{+}[/tex] that was released when [tex]1\; \rm mol[/tex] of [tex]\rm H_2SO_4[/tex] is dissolved in water. Since one mole of [tex]\rm NaOH[/tex] formula units could produce only one mole of [tex]\rm OH^{-}[/tex], it would take [tex]\rm 2\; mol[/tex] of [tex]\rm NaOH[/tex] formula units to produce that [tex]2\; \rm mol[/tex] of [tex]\rm OH^{-}[/tex] for reacting with [tex]1\; \rm mol[/tex] of [tex]\rm H_2SO_4[/tex].
Which statement is a scientific law?
A.Scientists use genes to explain why evolution happens.
B.Genes are long patterns that are similar to computer codes.
C.A person’s traits are controlled by different forms of a gene.
D.The discovery of genes changed how scientists think about life.
Answer:
A.Scientists use genes to explain why evolution happens.
Explanation:
:)
which accurately describes development?
Answer:
changing while growing
Explanation:
Answer: the answer is a
A(n) __________ can be added to milk to neutralize it.
why is copper different than copper ore gives me reasons. Do this asap
Answer:
copper cathodes are normally referred to when talking about copper. Cathode is the purest form of copper and is the feedstock used to produce copper wire, cable, sheet, strip, tube, etc.
Explanation:
name two bases which react with dillute sulfuric acid to give zinc sulfate
Answer:
Zinc Carbonate
Zinc Nitrate
Explanation:
How much heat is added if 0.2067g of water is increased in temperature by 0.855
degrees C?
Answer:
0.756 J
Explanation:
Temperature change (delta T) = 0.855 degrees Celsius
Mass of water (m) = 0.2067 g
Specific heat capacity of water (c) = 4.28 J/g degrees C
Heat added = m * c * delta T
= (0.2067 * 4.28 * 0.855) J
= 0.756 J
Why you cannot add 0.3 moles of calcium fluoride directly to 1L of water to make a 0.3 M
solution ?
need help ASAP!
Answer:
Because it's not soluble in water, need to be heated acidic solution
Explanation:
Calcium Fluoride Formula: CaF2 Comprises of Ca2+ and F−
H2O = Water H+ O2- OH-
Insoluble in water
In order to dissolve a salt, you have to break apart the ions and hydrate them via a solvent.
Need to read
HSAB concept( Pearson acid-base concept) is an initialism for "hard and soft (Lewis) acids and bases"
So F- is a Halogen which is a Hard Base
And OH- is a Hard base as well
And H- is a soft base
So soft acids react best with soft bases and hard acids react best with hard bases.
Bases don't react with other bases.
Oxygen is released into the atmosphere by _____.
respiration
photosynthesis
denitrification
fixation
Answer:
your answer will be photosynthesis
Explanation:
For neap tides, what must the angular alignment be between the sun, earth and moon?
Answer:
The angular alignment is 90 degrees
Explanation:
The neap tide is a type of tide which occurs around seven days after a spring tide. This type of tide happens twice every month.
The tide is usually moderate and it exists when the sun and moon are usually at right angles to each other when it occurs. A right angle is also known as 90 degrees which validates the tide occurring at an angle 90.
Which substance is a mixture? Table salt, gasoline, aluminum, or carbon dioxide.
Answer:
gasoline
Explanation:
12. Aditya is stacking some cups. The diagram above shows the cups before they touch each other. Use the information in the diagram to answer the question.
After the cups have been touching for a while, which of the two bottom cups will be cooler, and why?
Answer:
please give more clarification
CHEM HELP PLEASE
a reaction that has been calculated to produce 346 g of CH3OH actually produced 312 g of CH3OH. what is it's percent yield?
Answer:
90.2%
Explanation:
% yield = actual yield/ theoretical yield * 100%
% yield = (312/346)*100% = 90.2%
Strontium, a group 2 element with an electron configuration of 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6 5s^2 , will form a _____ ion in a chemical bond.
+1
+2
-1
-2
Answer:
Strontium, a group 2 element with an electron configuration of 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² , will form a +2 ion in a chemical bond.
Explanation:
An ionic bond is produced between metallic and non-metallic atoms, where electrons are completely transferred from one atom to another. During this process, one atom loses electrons and another one gains them, forming ions. Usually, the metal gives up its electrons forming a cation to the nonmetal element, which forms an anion.
So an ion is an atom or group of atoms that have an electric charge. A cation is an ion that has a positive charge.
The alkali metals in the earth (Elements IIA) lose two electrons to form a 2+ cation. Strontium is an alkali metal that loses the two electrons belonging to 5s², forming the +2 ion.
Answer:
+2
Explanation:
___and ___exert pressure on the walls of the vessel in which they are carried out
A) Solid, liquid and Gases
B) Gases and solids
C) Liquids and gases
D) Solid and gases
Answer:
C) Liquids and gases
Explanation:
The correct answer would be liquids and gases.
The molecules of liquids and gases move randomly when held in a container. The random movement causes a collision between the molecules of the liquids/gases and between the walls of the container, creating pressure in the process. This is unlike the molecules of solids that vibrate about fixed positions.
Hence, the correct option is C.
does a periodic table indicate the occurrence of elements
Answer:
no
Explanation:
it only shows the atomic number and basically the chemical behavior of the element
The recommended dose of aspirin will yield approximately 100.0 micrograms/mL in the blood. How many molecules of aspirin (C9H8O4) are in a drop (0.100 mL) of blood?
Answer:
3.34x10¹⁶ molecules of aspirin are in a drop of blood
Explanation:
The recomended dose of aspirin in blood is 100.0μg/mL =
1x10⁻⁴g aspirin / mL of blood.
In a drop (0.100mL) there are:
0.100mL ₓ (1x10⁻⁴g aspirin / mL of blood) = 1x10⁻⁵g aspirin.
Molecular mass of aspirin is:
9C = 12.01g/mol ₓ 9 = 108.09g/mol
8H = 1.01g/mol ₓ 8 = 8.08g/mol
4O = 16g/mol ₓ 4 = 64g/mol
108.09 + 8.08 + 64 = 180.17g/mol
Thus, moles of aspirin in 1x10⁻⁵g are:
1x10⁻⁵g ₓ (1mol / 180.17g) = 5.55x10⁻⁸ moles of aspirin
In 1 mole, you have 6.022x10²³ molecules, thus:
5.55x10⁻⁸ moles of aspirin ₓ (6.022x10²³ molecules / 1 mole ) =
3.34x10¹⁶ molecules of aspirin are in a drop of bloodH3PO4 + Ca(OH)2 → Ca(H2PO4)2 + H2O
Given question is incomplete. The complete question is as follows.
Balance the following equation:
[tex]H_3PO_4 + Ca(OH)_2 \rightarrow Ca(H_2PO_4)_2 + H_2O[/tex]
Answer: The balanced chemical equation is as follows.
[tex]2H_3PO_4 + Ca(OH)_2 \rightarrow Ca(H_2PO_4)_2 + 2H_2O[/tex]
Explanation:
When a chemical equation contains same number of atoms on both reactant and product side then this equation is known as balanced equation.
For example, [tex]H_3PO_4 + Ca(OH)_2 \rightarrow Ca(H_2PO_4)_2 + H_2O[/tex]
Number of atoms on reactant side:
H = 5
P = 1
O = 6
Ca = 1
Number of atoms on product side:
H = 6
P = 2
O = 9
Ca = 1
In order to balance this equation, we will multiply [tex]H_3PO_4[/tex] by 2 on reactant side and we will multiply [tex]H_2O[/tex] by 2 on product side. Hence, the balanced chemical equation is as follows.
[tex]2H_3PO_4 + Ca(OH)_2 \rightarrow Ca(H_2PO_4)_2 + 2H_2O[/tex]
I NEED HELP PLEASE, THANKS! :)
Explain the process of sublimation. Name one substance that sublimes at room temperature and pressure.
Answer:
Here's what I get
Explanation:
Sublimation is the conversion of a solid directly to a gas, without passing through the liquid state.
It occurs when the molecules of a solid have absorbed enough heat (kinetic energy) for some molecules to overcome the attractive forces of their neighbours and escape directly into the vapor phase.
One substance that sublimes at room temperature and pressure is CO₂ (dry ice).
Naphthalene is a substance that sublimes at room temperature and pressure.
What do you mean the process of sublimation ?Sublimation is defined as a process in which solid converts into gas directly without converting into liquid.
In the sublimation process, the reaction is an endothermic reaction, as the chemical bonds between molecules are broken down in order to release them into the air. Therefore ,the energy is released and so it is an endothermic reaction.
The heat or energy required to change the state from solid to gas is called the enthalpy of sublimation .Generally, it is expressed as KJ/m o l. Sublimation only occurs at pressures and temperatures .
Hence , Naphthalene is a substance that sublimes at room temperature and pressure.
Learn more about sublimation ,here:
https://brainly.com/question/9967928
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What is the answer to this ?
Answer:
12.78 or 12.80 mostly like 12.78
Explanation:
calculate the ph of a solution containing 0.001 mol dm-3 Naoh
Answer:
pOH = - log [molarity of OH-] = - log [ molarity of NaOH] , assuming full dissociation. Thus, pOH = - log ( 0.001) = - (-3) = 3. Thus, the pH of 0.001 mol/dm3 NaOH solution is 11.
Explanation:
Hope it'll help!
