1. How many grams of carbon are in 0.688 g of carbon dioxide?

It is necessary to know the

molar mass of each element

of carbon dioxide (CO2). We can find

that information on the Periodic Table of

Elements:

- Carbon atomic mass: 12 g/mol

- Oxygen atomic mass: 16 g/mol

2nd)

We need to calculate the

molar mass of carbon dioxide

. As the molecule of CO2 has 1 mole of

carbon and 2 moles of oxygens, the

molar mass of the molcule is:

(1 x 12g/mol) + (2 x 16 g/mol) = 44 g/mol

3rd)

Finally, if 1 molecule of dioxide carbon

has 12g of carbon, we can use a

mathematical Rule of Tree to calculate

mow many grams of carbon are in

0.688g of carbon dioxide:

12gC - 44gC02

0.699gC • 44gC02

12gC

1 = 2.52gC02

SO,

there are 2.52g of carbon in 0.688g of

carbon dioxide

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2