IGCSE M1 Review

Two atoms of magnesium, Mg, react with one molecule of oxygen, O₂. What is the formula of the product?

• MgO

• MgO₂

• Mg₂O

• Mg₂O₂

Substance mysterious X was analyzed to contain 40.00% carbon (Ar: 40), 6.67% hydrogen (Ar: 1) and 53.33% oxygen (Ar: 16) by mass. It has a relative molecular mass of 60.0 gmol^-1.

What is its molecular formula?

• C₄H₈O₄

• C₆H₁₂O₆

• C₂H₄O₂

• CH₂O

A student thermally decomposes 24.8 g of CuCO3 (white powder in picture) and obtains 11.2g of CuO (black powder) together with carbon dioxide gas.

CuCO₃ -> CuO + CO₂

Ar Cu: 64, C: 12, O: 12

What is the percentage yield of CuO made?

• 55%

• 70%

• 82%

• 90%

For the Balanced Reaction: 3 Mg + 1 Fe₂O₃ → 3 MgO + 2 Fe; What is the Ratio of moles of MgO to moles Fe?

• 3mol Mg / 2 mol Fe
• 2 mol Mg/ 3 mol Fe
• 1 mol Fe/ 2 mol Fe
• 3 mol MgO / 2 mol Fe

2Na + 2H₂O → 2NaOH+ H₂
How many grams of hydrogen are produced if 120 g of Na are available?

• 5.2 g
• 2.6 g
• 690 g
• 45 g

What is Avogadro's number?

• 6.02 x 10²³

• 1 mole

• 600 million

• 6.02

One mole of carbon dioxide (CO₂) contains 6.02 x 10²³ _____.

• atoms

• formula units

• ions

• molecules

A mole is:

• The SI unit for mass

• The SI unit for the amount of a substance

• The SI unit for volume

• The SI unit for area

How many atoms are in 1 mole of Iodine (I)?

• 6.02 x 10²³

• 4.02 x 10²³

• 6.02 x 10²⁵

• 4.02 x 10²⁵

NaOH represents 

• Sodium bicarbonate
• Sodium carbonate
• Sodium Chloride
• Sodium Hydroxide