On-line calculations Quiz 8. Deducing empirical and molecular formula (using mole concept)

0.55g of boron combined with 1.2g of oxygen. Deduce the empirical formula of boron oxide.
(relative atomic masses, A_r: B = 11, O = 16) [efm-1]
1. B₂O₃
2. BO
3. B₂O
4. BO₂
1.35g of aluminium was burned in excess fluorine to form 4.2g of aluminium fluoride. Deduce the empirical formula of aluminium fluoride.
(relative atomic masses, A_r: Al = 27, F = 19) [efm-2]
1. AlF
2. AlF₃
3. Al₃F
4. AlF₂
3.4g of an unusual carbon oxide contained 1.8g of carbon. Deduce the empirical formula of the carbon oxide.
(relative atomic masses, A_r: C=12, O=16) [efm-3]
1. CO
2. CO₂
3. C₃O₂
4. C₂O₃
In an experiment 3.175g of copper combined with 0.400g of oxygen. What is the empirical formula of the copper oxide?
(relative atomic masses, A_r: Cu = 63.5, O = 16) [efm-4]
1. CuO
2. CuO₂
3. Cu₂O₂
4. Cu₂O
8.875g of chlorine combined with 14.25g of fluorine. What is the formula of the chlorine fluoride?
(relative atomic masses, A_r: Cl = 35.5, F = 19) [efm-5]
1. ClF₃
2. Cl₃F
3. ClF
4. ClF₂
A gas formed by the combination of hydrogen and sulphur consited of 5.88% hydrogen and 94.12% sulphur. What is its empirical formula?
(relative atomic masses, A_r: H = 1, S = 32) [efm-6]
1. HS
2. H₂S
3. HS₂
4. H₂S₂
5.08g of iodine combined with 1.6g of oxygen. What is the formula of the iodine oxide?
(relative atomic masses, A_r: I = 127, O = 16) [efm-7]
1. IO₅
2. I₂O
3. I₂O₅
4. I₂O₃
2.8g of lithium was heated in a stream of air forming 6.0g of lithium oxide. What is its formula?
(relative atomic masses, A_r: Li = 7, O =16) [efm-8]
1. LiO
2. LiO₂
3. LiO₃
4. Li₂O
A iron-copper sulphide ore consisted of 30.5% iron, 34.6% copper, and 34.9% sulphur. What is the empirical formula of the ore?
(relative atomic masses, A_r: Fe = 56, Cu = 63.5, S = 32) [efm-9]
1. FeCuS₂
2. FeCuS
3. FeCu₂S
4. Fe₂CuS₂
0.48g of magnesium combined with 3.20g of bromine. What is the formula of magnesium bromide?
(relative atomic masses, A_r: Mg = 24, Br = 80) [efm-10]
1. Mg₂Br
2. MgBr₂
3. MgBr
4. MgBr₃
0.7g of nitrogen combined with 5.325g of chlorine. Deduce the formula of nitrogen chloride.
(relative atomic masses, A_r: N = 14, Cl = 35.5) [efm-11]
1. NCl
2. NCl₂
3. NCl₃
4. N₃Cl
Fluorine oxide consists of 70.4% fluorine and 29.6% oxygen by mass. Deduce the formula of fluorine oxide.
(relative atomic masses, A_r: F = 19, O = 16) [efm-12]
1. FO
2. FO₂
3. FO₃
4. F₂O
47.6g of uranium combined with 22.8g of fluorine. What is the empirical formula of this uranium fluoride?
(relative atomic masses, A_r: U = 238, F = 19) [efm-13]
1. UF₆
2. UF₃
3. UF₂
4. UF₄
10.35g of lead was heated in excess oxygen. If 11.95g of a lead oxide was formed, deduce its empirical formula.
(relative atomic masses, A_r: Pb = 207, O = 16) [efm-14]
1. PbO
2. PbO₂
3. Pb₂O
4. PbO₃
10.8g of aluminium combined with 19.2g of sulphur. What is the empirical formula of aluminium sulphide?
(relative atomic masses, A_r: Al = 27, S = 32) [efm-15]
1. Al₃S₂
2. AlS₃
3. Al₂S₃
4. AlS₂
A hydrocarbon of molecular mass 30 consisted of 80% carbon and 20% hydrogen by mass. Deduce the molecular formula of the hydrocarbon.
(relative atomic masses, A_r: C = 12, H = 1) [efm-16]
1. CH₃
2. C₂H₃
3. CH₁₈
4. C₂H₆
6g of carbon combines with 71g of chlorine. What is the formula of the carbon chloride?
(relative atomic masses, A_r: C = 12, Cl = 35.5) [efm-17]
1. CCl₄
2. C₄Cl
3. CCl₂
4. C₂Cl
An organic compound consisted of 52.18% carbon, 13.04% hydrogen and 34.78% oxygen by mass. Deduce its empirical formula.
(relative atomic masses, A_r: C = 12, H = 1, O = 16) [efm-18]
1. CH₆O
2. C₂H₆O
3. C₂H₆O₂
4. CH₃O
An chlorinated hydrocabon molecule consisted of 37.21% carbon, 7.75% hydrogen and 55.04% chlorine by mass. Deduce its empirical formula.
(relative atomic masses, A_r: C = 12, H = 1, Cl = 35.5) [efm-19]
1. C₂H₆Cl
2. CH₃Cl
3. C₂H₅Cl
4. C₂H₄Cl₂
A calcium mineral consisted of 29.4% calcium, 23.5% sulphur and 47.1% oxygen by mass. Calculate the empirical formula of the mineral.
(relative atomic masses, A_r: Ca = 40, S = 32, O = 16) [efm-20]
1. CaSO₂
2. CaSO₃
3. Ca₂SO₄
4. CaSO₄
A salt consisted of 27.06% sodium, 16.47% nitrogen and 56.47% oxygen by mass. Deduce the formula of the salt.
(relative atomic masses, A_r: Na = 23, N = 14, O = 16) [efm-21]
1. NaNO₃
2. NaNO₂
3. Na₂NO₃
4. NaNO
A brominated hydrocarbon consisted of 12.77% carbon, 2.13% hydrogen and 85.10% bromine by mass. If its molecular mass is 188, deduce the molecular formula of the molecule.
(relative atomic masses, A_r: C = 12, H = 1, Br =80) [efm-22]
1. CH₂Br
2. C₂H₄Br₂
3. CH₁₆Br₂
4. C₂H₆Br₂
It was found that 24g of carbon was combined with 5g of hydrogen in a hydrocarbon. If its molecular mass was 58, what is its molecular formula?
(relative atomic masses, A_r: C = 12, H = 1) [efm-23]
1. C₂H₅
2. C₃H₈
3. C₄H₁₀
4. C₃H₂₂
A hydrocarbon consisted of 92.3% carbon and 7.7% hydrogen. If its molecular mass is 78, work out its molecular formula.
(relative atomic masses, A_r: C = 12, H = 1) [efm-24]
1. C₅H₁₈
2. CH
3. CH₆
4. C₆H₆
A carbohydrate on analysis consisted of 40.00% carbon, 6.67% hydrogen and 53.33% oxygen. If its molecular mass is 180, deduce the molecular formula of the carbohydrate.
(relative atomic masses, A_r: C = 12, H = 1, O = 16) [efm-25]
1. C₆H₁₂O₆
2. CH₂O
3. C₅H₈O₇
4. C₃H₆O₃
7.75g of an alcohol consisted of 3.00g carbon, 0.75g hydrogen and 4.00g oxygen. If its molecular mass is 62, work out the molecular formula.
(relative atomic masses, A_r: C = 12, H = 1, O = 16) [efm-26]
1. C₃H₁₀O
2. C₂H₆O₂
3. CH₃O
4. C₂H₆O
An alcohol consisted of 39.13% carbon, 8.70% hydrogen and 52.17% oxygen. If its molecular mass is 92, deduce its molecular formula.
(relative atomic masses, A_r: C = 12, H = 1, O = 16) [efm-27]
1. CH₂O
2. C₃H₆O₃
3. C₃H₈O₃
4. C₂H₄O₄
In an experiment 6g of carbon combined with 19g of fluorine. Calculate the molecular formula of the compound formed if the molecular mass of it is 100.
(relative atomic masses, A_r: C = 12, F = 19) [efm-28]
1. CF₂
2. C₄F₂
3. CF₄
4. C₂F₄
A compound of hydrogen and oxygen was made up of 0.5g hydrogen and 8g of oxygen. What is its empirical formula?
(relative atomic masses, A_r: H = 1, O = 16) [efm-29]
1. HO
2. H₂O₂
3. H₂O
4. HO₂
A lithium compound consisted of 7g of lithium combined with 16g of sulphur and 32g of oxgen. What is the empirical formula of the compound?
(relative atomic masses, A_r: Li = 7, S = 32, O = 16) [efm-30]
1. LiSO₂
2. Li₂SO₄
3. LiSO₄
4. Li₂SO₃
58g of a sodium phosphate salt consisted of 34.5g of sodium, 15.5g of phosphorus and 32.0g of oxygen. What is the simplest formula of the compound?
(relative atomic masses, A_r: Na = 23, P = 31, O = 16) [efm-31]
1. Na₄PO₃
2. Na₂PO₄
3. Na₃PO₄
4. Na₂PO₃
A sodium compound consisted of 46g of sodium combined with 254g of iodine and 128g of oxygen. What is the compounds empirical formula?
(relative atomic masses, A_r: Na = 23, I = 127, O = 16) [efm-32]
1. NaIO₃
2. NaIO₂
3. Na₂IO₄
4. NaIO₄
16g of copper, after heating in oxygen, formed 20g of a copper oxide. What is the formula of the oxide?
(relative atomic masses, A_r: Cu = 64, O = 16) [efm-33]
1. CuO
2. CuO₂
3. Cu₂O
4. CuO₃
An oxide of carbon consisted of 3g of carbon combined with 4g of oxygen. What is the formula of the oxide?
(relative atomic masses, A_r: C = 12, O = 16) [efm-34]
1. CO₂
2. CO
3. C₂O4
4. C₂O
1.95g of potassium combined with 4.00g of bromine. What is the empirical formula of the compound?
(relative atomic masses, A_r: K = 39, Br = 80) [efm-35]
1. K₂Br
2. KBr₂
3. KBr
4. KBr₃
5g of calcium on heating in oxygen formed 7g of calcium oxide. What is the simplest formula of calcium oxide?
(relative atomic masses, A_r: Ca = 40, O = 16) [efm-36]
1. CaO₂
2. Ca₂O
3. CaO₃
4. CaO
13g of zinc combined with 6.4g of sulphur. What is the empirical formula of zinc sulphide?
(relative atomic masses, A_r: Zn = 65, S = 32) [efm-37]
1. ZnS
2. ZnS₂
3. Zn₂S
4. ZnS₃
An oxide of copper contained 80% copper and 20% oxygen by mass. What is the formula of the copper oxide?
(relative atomic masses, A_r: Cu = 64, O = 16) [efm-38]
1. Cu₂O
2. CuO
3. CuO₂
4. CuO₃
If magnesium oxide consists of 60% magnesium and 40% oxygen, what is its simplest formula?
(relative atomic masses, A_r: Mg = 24, O = 16) [efm-39]
1. Mg₂O
2. MgO₂
3. MgO
4. MgO₃
2.3g of sodium combined with 1.6g of sulphur. What is the formula of sodium sulphide?
(relative atomic masses, A_r: Na = 23, S = 32) [efm-40]
1. NaS
2. NaS₂
3. NaS₃
4. Na₂S
In an experiment 1.28g of copper combined with 0.16g of oxygen. What is the formula of the copper oxide?
(relative atomic masses, A_r: Cu = 64, O = 16) [efm-41]
1. Cu₂O
2. CuO
3. CuO₂
4. CuO₃
13.8g of sodium combined with 6.2g of phosphorus. What is the formula of sodium phosphide?
(relative atomic masses, A_r: Na = 23, P = 31) [efm-42]
1. NaP
2. Na₃P
3. NaP₂
4. Na₂P
10g of calcium combined with 40g of bromine. What is the formula of calcium bromide?
(relative atomic masses, A_r: Ca = 40, Br = 80) [efm-43]
1. CaBr
2. Ca₂Br
3. CaBr₂
4. CaBr₃
22g of boron combined with 114g of fluorine. What is the empirical formula of boron fluoride?
(relative atomic masses, A_r: B = 11, F = 19) [efm-44]
1. BF
2. BF₂
3. B₃F
4. BF₃
1.2g of titanium, after heating in oxygen, formed 2.0g of a titanium oxide. What is the empirical formula for the titanium oxide?
(relative atomic masses, A_r: Ti = 48, O = 16) [efm-45]
1. TiO₂
2. TiO
3. Ti₂O
4. TiO₃
0.800g of magnesium reacted with 8.47g of iodine. Calculate the empirical formula for magnesium iodide.
(relative atomic masses, A_r: Mg = 24, I = 127) [efm-46]
1. MgI
2. MgI₂
3. Mg₂I
4. MgI₃

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On-line calculations Quiz 8. Deducing empirical and molecular formula (using mole concept)

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