The equation for the reaction between hydrogen gas and oxygen gas is:

2H2(g) + O2(g) ---> 2H2O(l)

i) How much hydrogen will react with 8g of oxygen?

ii) how much water will be formed when 6g of hydrogen react?

i would appreciate your help.

Both i) and ii) are simple stoichiometry problems (as opposed to limiting reagent problems).I have posted an example problem of this type. Just follow the steps.

http://www.jiskha.com/science/chemistry/stoichiometry.html

i) To find out how much hydrogen will react with 8g of oxygen, we need to use the stoichiometry of the balanced chemical equation.

The balanced equation tells us that 2 moles of hydrogen react with 1 mole of oxygen to produce 2 moles of water.

First, we need to calculate the number of moles of oxygen in 8g of oxygen. To do this, we'll use the molar mass of oxygen, which is 32 g/mol.

Number of moles of oxygen = mass of oxygen / molar mass of oxygen
Number of moles of oxygen = 8g / 32 g/mol
Number of moles of oxygen = 0.25 mol

According to the balanced equation, 2 moles of hydrogen react with 1 mole of oxygen. So, if 0.25 mol of oxygen reacts, we'll need (2 * 0.25) = 0.5 moles of hydrogen.

Finally, we can calculate the mass of hydrogen in 0.5 moles by using the molar mass of hydrogen, which is 2 g/mol.

Mass of hydrogen = number of moles of hydrogen * molar mass of hydrogen
Mass of hydrogen = 0.5 mol * 2 g/mol
Mass of hydrogen = 1 g

Therefore, 8g of oxygen will react with 1g of hydrogen.

ii) To find out how much water will be formed when 6g of hydrogen reacts, we'll use the same approach.

First, let's calculate the number of moles of hydrogen in 6g of hydrogen using the molar mass of hydrogen, which is 2 g/mol.

Number of moles of hydrogen = mass of hydrogen / molar mass of hydrogen
Number of moles of hydrogen = 6g / 2 g/mol
Number of moles of hydrogen = 3 mol

According to the balanced equation, 2 moles of hydrogen react with 2 moles of water. Therefore, if 3 moles of hydrogen react, we'll produce (2 * 3) = 6 moles of water.

Finally, we can calculate the mass of water in 6 moles using the molar mass of water, which is 18 g/mol.

Mass of water = number of moles of water * molar mass of water
Mass of water = 6 mol * 18 g/mol
Mass of water = 108 g

Therefore, 6g of hydrogen will produce 108g of water.