How many grams of oxygen gas are needed for the complete

Question

If sodium peroxide is added to water, elemental oxygen gas is generated:

Na₂O₂(s) + H₂O(l) → NaOH(aq) + O₂(g)

Suppose 1.80 g of sodium peroxide is added to a large excess of water. What mass of oxygen gas will be produced?

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2) When small quantities of elemental hydrogen gas are needed for laboratory work, the hydrogen is often generated by chemical reaction of a metal with acid. For example, zinc reacts with hydrochloric acid, releasing gaseous elemental hydrogen:

Zn(s) + 2HCl(aq) → ZnCl₂(aq) + H₂(g)

What mass of hydrogen gas is produced when 1.80 g of zinc is reacted with excess aqueous hydrochloric acid?

__g

3) The gaseous hydrocarbon acetylene, C₂H₂, is used in welders' torches because of the large amount of heat released when acetylene burns with oxygen.

2C₂H₂(g) + 5O₂(g) → 4CO₂(g) + 2H₂O(g)

How many grams of oxygen gas are needed for the complete combustion of 1.1×10² g of acetylene?

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