Question

5. A penny weighs about 2.5 g. How many moles of pennies would be required to equal the mass of the moon (7.3x10^24 kg)

6. Vodka is 40% ethanol. How many moles of ethanol are in a 750 ml bottle of vodka? The density of Ethanol is 0.79 g/ml.

Answer 1

5. 1.16 x
`10^(26)` 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.

Step-by-step 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
`10^(24)` kg

number of moles =
`(mass)/(atomic mass of 1 mole)`

number of moles =
`(2.5)/(62.93)`

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
`10^(27)` grams

`(0.039)/(2.5) =(x)/(7.3 X 10^(27) )`

x = 1.16 x
`10^(26)` 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
`10^(26)` .

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 =
`(mass)/(volume)`

density x volume = mass

0.79 x 750 = 592.5 grams

number of moles =
`(mass)/(atomic mass of 1 mole)`

number of moles of ethanol =
`(592.5)/(46.07)`

= 12.86 moles of ethanol