How can we prevent land pollution?
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5. 1.16 x moles moles of pennies would be required to equal the mass of the moon.
6. 12.86 moles of ethanol are in a 750 ml bottle of vodka.
Explanation:
5 .Data given:
mass of penny = 2.5 grams
atomic mass of penny = 62.93 grams/mole
moles present in mass of the moon given as = 7.3 x kg
number of moles =
number of moles =
0.039 moles of penny is present in 2.5 grams
0.039 moles of penny in 2.5 grams of it
so, x moles in 7.3 X grams
x = 1.16 x moles
so when the mass of the penny given is equal to the mass of moon, number of moles of penny present is 1.1 x .
6.
Given:
vodka = 40% ethanol
volume of vodka bottle = 750 ml
moles of ethanol =?
density of ethanol =0.79 g/ml
atomic mass of ethanol = 46.07 grams/mole
so, from the density of ethanol given we can calculate how much ethanol is present in the solution.
density =
density x volume = mass
0.79 x 750 = 592.5 grams
number of moles =
number of moles of ethanol =
= 12.86 moles of ethanol
25.9 kJ/mol. (3 sig. fig. as in the heat capacity.)
<h3>Explanation</h3>The process:
.
How many moles of this process?
Relative atomic mass from a modern periodic table:
- K: 39.098;
- N: 14.007;
- O: 15.999.
Molar mass of :
.
Number of moles of the process = Number of moles of dissolved:
.
What's the enthalpy change of this process?
for
. By convention, the enthalpy change
measures the energy change for each mole of a process.
.
The heat capacity is the least accurate number in these calculation. It comes with three significant figures. As a result, round the final result to three significant figures. However, make sure you keep at least one additional figure to minimize the risk of rounding errors during the calculation.