Zn + 2 hcl zncl2 + h2

you are asked the following question: in the reaction above, if you start with 10 grams of zinc, how many moles of hydrogen will be produced?

before solving for moles of hydrogen produced, you must first solve for moles of zinc. how do you convert grams of zinc to moles of zinc?

30
zn
65.39
zinc

a. multiply 5 grams of zn x (1 mol zn/65.39 g).
b. multiply 10 grams of zn x (1 mol zn/65.39 g).
c. multiply 10 grams of zn x (65.39 g/1 mol zn).
d. multiply 10 grams of zn x (2 mol hcl/36.45 g).

0.153 moles of hydrogen.

B) Multiply 10 grams of Zn x (1 mol Zn/65.39 g)

Explanation:

Given data:

Mass of zinc = 10 g

Moles of hydrogen = ?

Solution:

Chemical equation:

Zn + 2HCl  →  ZnCl₂ +  H₂

Number of moles of zinc:

Number of moles of zinc = mass/ molar mass

Number of moles of zinc = 10 g/ 65.4 g/mol

Number of moles of zinc = 0.153 mol

Now we will multiply the moles of Zn with hydrogen:

                     Zn            :            H₂

                      1              :              1

                     0.153       :            0.153

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3