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Iteru [2.4K]
3 years ago
9

The mass number of an atom is equal to which of the following?

Chemistry
1 answer:
seropon [69]3 years ago
5 0

the answer is c, the number of protons plus the number of neutrons in a nucleus

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How many atoms of gold are in a pure gold coin weighing 12.0g?
grigory [225]
12.0g x 1 mol / 63.546g = 0.188839581mol 

<span>So, for every 1 mole, we have 6.022 x 10^23 of whatever we're measuring. This gives us a conversion factor of (1 mole / 6.022 x 10^23 atoms) or (6.022 x 10^23 atoms / 1 mole).
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0.188839581 mol x (6.022 x 10^23 atoms) / 1 mol = 1.137191955 x 10^23 

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3 0
3 years ago
Rank the following measurements in order from least to greatest
Harman [31]
It’s
1.A
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4 0
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ANEK [815]

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4 0
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What can you conclude about these two reactions based on the chemical equations? Reaction A: 6CO2(g) + 6H2O(l) + sunlight ? C6H1
OlgaM077 [116]

Given reactions:

(A)   6CO2(g) + 6H2O(l) + sunlight → C6H12O6(aq) + 6O2(g)

(B)  2H2(g) + O2(g) → 2H2O(g) + energy

Exothermic reactions are those which proceed with the release of heat/energy. In contrast, endothermic reactions proceed with the absorption of energy in the form of heat or light.

Since reaction A required sunlight, it is endothermic. Reaction B releases energy, hence exothermic

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8 0
2 years ago
Calculate the standard entropy of vaporization of ethanol, C2H5OH, at 285.0 K, given that the molar heat capacity at constant pr
MArishka [77]

Answer: The standard entropy of vaporization of ethanol is 0.275 J/K

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C_2H_5OH(l)\rightleftharpoons C_2H_5OH(g)

Using Gibbs Helmholtz equation:

\Delta G=\Delta H-T\Delta S

For a phase change, the reaction remains in equilibrium, thus \Delta G=0

\Delta H=T\Delta S

Given: Temperature = 285.0 K

\Delta H=78.3J/mol

Putting the values in the equation:

78.3J=285.0K\times \Delta S

\Delta S=0.275J/K

Thus  the standard entropy of vaporization of ethanol is 0.275 J/K

4 0
3 years ago
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