Chemistry Questions

What is the relative molecular mass for the compound Fe2(SO4)3 if the relative atomic mass (Ar) of Fe=56, S=32, and O=16?

• 208

• 304

• 156

• 334

• 400

Given Ar H=1, C=12, O=16. What is the relative molecular mass (Mr) of CH3COOH?

• 60

• 56

• 59

• 54

• 58

If Ar Ca = 40, C = 12, O = 16 and Avogadro's number = 6.02×10^23, how many molecules are in 50 grams of CaCO3?

• 1.204 × 10^23

• 6.02 × 10^23

• 6.02 × 10^22

• 3.01 × 10^22

• 3.01 × 10^23

Calculate the mass of 0.1 mol of limestone (CaCO3) given Ar Ca = 40, Ar C = 12 and Ar O = 16.

• 25 grams

• 20 grams

• 15 grams

• 12.5 grams

• 10 grams

If Ar C = 12 and O = 16, what is the volume of 8.8 grams of CO2 gas at standard conditions (STP)?

• 22.4 liters

• 4.48 liters

• 8.96 liters

• 6.72 liters

• 2.24 liters

Pyrimidine consists of 60% carbon, 5% hydrogen, and the rest nitrogen (Ar H=1, C=12, N=14). If the relative molecular mass of pyrimidine is 80, what is its molecular formula?

• C4H4N2

• C6H6N3

• C2H2N

• C3H2N4

• C5H6N

In 100 grams of a compound, there are 40% calcium, 12% carbon, and 48% oxygen. If Ar Ca = 40, C = 12, and O = 16, what is the empirical formula of the compound?

• CaCO

• Ca2CO3

• CaCO2

• CaC2O

• CaCO3

A total of 3.2 grams of CH4 gas is burned with 16 grams of O2 according to the reaction: CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O(l). What are the initial moles of CH4 gas and O2?

• 0.1 mol CH4 and 0.2 mol O2

• 0.1 mol CH4 and 0.5 mol O2

• 0.2 mol CH4 and 0.2 mol O2

• 0.2 mol CH4 and 0.4 mol O2

• 0.2 mol CH4 and 0.5 mol O2

What is the mass of CO2 produced from burning 3.2 grams of CH4 with 16 grams of O2?

• 4.4 grams

• 3.2 grams

• 8.8 grams

• 16 grams

• 17.6 grams

What is the leftover substance after burning 3.2 grams of CH4 with 16 grams of O2?

• Gas CH4

• Gas CO2

• Gas O2

• Gas CH4 and O2

• H2O