1 What do strong acids and strong bases have in common?A They both partially dissociate, with reverse reactions occurring.
B They both dissociate completely, with little or no reverse reactions.
C They both remain intact when placed in water, with no dissociation taking place.
D They both dissociate completely, with reverse reactions constantly taking place.
2 What happens when the kinetic energy of molecules increases so much that electrons are released by the atoms, creating a swirling gas of positive ions and negative electrons?
A Matter changes to a solid state.
B Matter changes to a liquid state.
C Matter changes to a plasma state.
D Matter changes to a gaseous state.
3 Consider a balloon that has a volume V. It contains n moles of gas, it has an internal pressure of P, and its temperature is T. If the balloon is heated to a temperature of 15.5T while it is placed under a high pressure of 15.5P, how does the volume of the balloon change?
A It doubles.
B It stays the same.
C It increases greatly.
D It decreases slightly.
Answers
1) Answer is: B They both dissociate completely, with little or no reverse reactions.
Some of strong acids: HNO₃(nitric acid), HCl(hydrochloric acid), H₂SO₄(sulfuric acid), HI(hydroiodic acid). Strong bases are: sodium hydroxide (NaOH), barium hydroxide (Ba(OH)₂).
For example, hydrochloric acid, completely dissociate in water and give large amount of hydrogen ions (H⁺): HCl(aq) → H⁺(aq) + Cl⁻(aq).
Sodium hydroxide completely dissociate in water:
NaOH(aq) → Na⁺(aq) + OH⁻(aq).
2) Answer is: C Matter changes to a plasma state.
Plasma is a an ionised gas with highly electrical conductivity.
In solid, molecules are closely packed, stiff and do not changes of shape or volume. Solid object (for example iron) does not take on the shape of its container.
Liquids have definite volume, but no fixed shape.
Gases (for example nitrogen and neon) not have definite volume and fixed shape, it depends on its container.
3) Answer is: B It stays the same.
p₁ = P; initial pressure.
p₂ = 15.5 P; final pressure.
V₁ = V: initial volume.
V₂ = ?: final volume.
T₁ = T; initial temperature.
T₂ = 15.5T; final temperature.
The combinated gas law: The volume of a given amount of gas is proportional to the ratio of its Kelvin temperature and its pressure: p₁·V₁/T₁ = p₂·V₂/T₂.
P·V/T = (15.5P · V₂) / 15.5 T.
V₂ = V₁ = V.
Answer:
1). B
2). C
3). B
Explanation:
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Which statement must be true about a chemical system at equilibrium?(1) The forward and reverse reactions stop.(2) The concentration of reactants and products are equal.(3) The rate of the forward reaction is equal to the rate of the reverse reaction.(4) The number of moles of reactants is equal to the number of moles of product.
Answers
Answer: non metal
Explanation:
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The sample described is most likely a sulfur solid.
Explanation:
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Learn more about Characteristics of sulfur solids here:
#SPJ3
is an endothermic process. A 6.1589-g sample of the solid is placed in an evacuated 4.000-L vessel at exactly 24°C. After equilibrium has been established, the total pressure inside is 0.709 atm. Some solid NH4HS remains in the vessel.
(a) What is the KP for the reaction?
(b) What percentage of the solid has decomposed?
(c) If the volume of the vessel were doubled at constant temperature, what would happen to the amount of solid in the vessel?
Answers
Answer:
(a) Kp = 0.126
(b) 48.1 %
(c) More of the solid will decompose, therefore it will decrease.
Explanation:
(a) We have here the equilibrium decomposition of NH₄HS, according to the equation:
NH₄HS (s) ⇄ NH₃ (g) + H₂S
with an equlibrium cosnstant, Kp, given by
Kp = pNH₃ x pH₂S
where pNH3 and pH₂S are the partial pressures of NH₃ and H₂S .
Since 1 mol NH₃ is produced for every 1 mol H₂S, it follows that the partial pressure of NH₃ is equal to the partial pressure of H₂S ( from ideal gas law the pressure is proportional to number of mol):
pNH₃ = pH₂S = 1/2 (0.709) atm = 0.355 atm
and
Kp = 0.355 x 0.355 = (0.3545) ² = 0.126
(b) To solve this part we need to do a calculation based on the stoichiometry of the reaction by calculating the number of moles, n, a partial pressure of 0.355 atm represent.
From the ideal gas law we can calculate it:
PV = nRT ⇒ n = PV/RT
where P = 0.355 atm, V = 4.000 L, T = ( 24 + 273 ) K, and R is the gas constant 0.08205 Latm/Kmol.
n = 0.355 atm x 4.000 L / 0.08205 Latm/Kmol x 297
n = 0.058 mol
Now we can relate this 0.058 mol of NH₃ ( or H₂S ) to the number of moles of moles of NH₄HS that must have decompesed. Since it is a 1: 1 ratio:
(1 mol NH₄HS / 1 mol NH₃ ) x 0.058 mol NH₃ = 0.058 mol NH₄HS
Having the molar mass of NH₄HS, 51.11 g/mol we can calculate its mass:
0.058 mol NH₄HS x 51.11 g/mol = 2.9644 g
Percentage decomposition is then equal to:
2.9644 / 6.1589 g x 100 g = 48.1 %
(c) If the volume of the vessel, effectively we are reducing the pressure by a half , and the system will react according to LeChatelier's principle by producing more gaseous products to reach equilibrium again. Therefore, more of the solid NH₄HS will decompose, and the amount of it will we reduced compared to the previous part.
Answers
Answer:
76.3 g of 1 mole of element Z
Explanation:
According to Avogadro’s number the number of particles in 1 mole of a substance is 6.023 x 10²³.
The mass of 3 x 10²³ particles is 38g
Therefore, the mass of 6.023 x 10²³ is = 76.3 g
How many atoms in all are in one molecule of sucrose?
Answers
Answer:
45
Explanation:
There are 12 Carbons
There are 22 Hydrogens
There are 11 Oxygens.
I think the answer is either 0 or 45. But the wording is very sloppy. It is not really atoms that are present. There are ions.
Go with 45 but hold your nose when writing your answer.
Answers
Answer:
Exergonic process
Explanation:
A reaction in which the change in free energy is negative is what is termed an exergonic reaction. Energy is released into the surrounding medium in this type of reaction.
When pellets of NaoH is dissolved in water, energy in the form of heat is released into the medium and the solution gets hot.
Hence, the dissolution of NaoH in water is said to be exergonic.
Select one or more:
a. Chlorine forming a solid precipitate
b. Bubbles forming from hydrogen gas production
c. Solid zinc dissolving
d. Bubbles forming from chlorine gas production