Relative Formula Mass Quiz
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5 questions, one answer each
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1. What is the relative formula mass (Mr) of a compound?
- A. The mass of one atom of the compound in grams
- B. The sum of the relative atomic masses of all the atoms shown in its formula
- C. The number of moles in one gram of the compound
- D. The percentage of each element in the compound
2. What is the Mr of methane, CH4 (Ar: C = 12, H = 1)?
- A. 13
- B. 16
- C. 17
- D. 12
3. In the formula Al2(SO4)3, how many oxygen atoms must be included when calculating Mr?
- A. 3
- B. 4
- C. 8
- D. 12
4. What is the Mr of ammonium nitrate, NH4NO3 (Ar: N = 14, H = 1, O = 16)?
- A. 62
- B. 70
- C. 80
- D. 44
5. A student calculates the Mr of Mg(NO3)2 (Ar: Mg = 24, N = 14, O = 16) and gets 86. What error have they most likely made?
- A. They forgot to include the magnesium atom
- B. They only counted one nitrate group instead of two
- C. They used the wrong Ar for oxygen
- D. They calculated percentage composition instead of Mr