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ASChemistryCIEExam Questions2. Atoms, Molecules & Stoichiometry2.3 Formulas

Formulas (CIE AS Chemistry)

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2.3 Formulas

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11 mark

When the following equation is balanced correctly, using the smallest whole number coefficients, which row represents the coefficients?

__ Mg3N2 (s)  + __H2O (l) → __Mg(OH)2 (aq) + __NH3 (aq)

 

Mg3N2

H2O

Mg(OH)2

NH3

A

1

6

3

2

B

1

3

3

1

C

2

6

2

2

D

2

6

3

2

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    21 mark

    Which one of the following is the correct net ionic equation for the reaction (if one occurs) between CaCl2 and AgNO3?

    • Ca2+ (aq) + 2AgNO3 (aq) → 2Ag+ (s) + Ca(NO3)2 (aq)

    • CaCl2 (aq) + 2Ag+ (aq) → 2AgCl (s) + Ca2+ (aq)

    • Ca2+ (aq) + 2NO3- (aq) → Ca(NO3)2 (aq)

    • Ag+ (aq) + Cl- (aq) → AgCl (s)

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    31 mark

    Which one of the following is the correct net ionic equation for the reaction (if one occurs) between NaC2H3O2 (aq) and HCl (aq)?

    • C2H3O2- (aq) + HCl (aq) → CCl- (aq) + 2H2 (aq) + CO2 (aq)

    • C2H3O2- (aq) + H+ (aq) →  HC2H3O2 (aq)

    • Na+ (aq) + Cl- (aq) → NaCl (aq)

    • NaC2H3O2 (aq) + H+ (aq) → HC2H3O2 (aq) + Na+ (aq)

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    41 mark

    Use of the data booklet is relevant to this question.

    A compound was found to be 52.2% by weight carbon, 13.0% hydrogen and 34.8% oxygen.  

    What is the empirical formula of this compound?

    • C2H4O2

    • C4H13O2

    • C2H6O

    • C6H2O

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    51 mark

    Use of the data booklet is relevant to this question.

    A sample of hydrated calcium sulfate, CaSO4∙xH2O, has a relative formula mass of 172.2 

    What is the value of x?

    • 1

    • 2

    • 3

    • 4

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    11 mark

    Use of the data booklet is relevant to this question

    A hydrated carbonate of an unknown Group 1 metal has the formula X2CO3∙10H2O and is found to have a relative formula mass of 286. 

    What is the group 1 metal?

    • Rb

    • K

    • Na

    • Li

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    21 mark

    The diagram below shows the skeletal formula of phenazine.

    yQO~lJkJ_image-1

    What is the empirical formula of phenazine?

    • C6H6N

    • C12H8N2

    • C6H4N

    • C12H12N2

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    31 mark

    Use of the data booklet is relevant to this question.

    An additive in leaded petrol is composed of lead, carbon and hydrogen only. The compound contains 6.19% hydrogen and 29.7% carbon by mass.

    What is the value of x in the empirical formula PbC8Hx?

    • 6

    • 5

    • 20

    • 16

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    1
    Sme Calculator    1 mark

    An organic compound has the composition by mass:

    C, 53.33 %; H, 11.11%; O, 35.56%.

    What is the empirical formula of the organic compound?

    • C4H8O2

    • C4H10O2

    • C2H4O

    • C2H5O

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    2
    Sme Calculator    1 mark

    A compound has the composition by mass:

    H, 5.00%;    N, 35.00%;   O, 60.00%.

    Which compound has this composition?

    • HNO3 

    • NH4NO3 

    • HNO2 

    • NH2OH

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    3
    Sme Calculator    1 mark

    A sample of a compound M contains 1.46 g of carbon, 0.482 g of hydrogen and 1.69 g of nitrogen.
    What is the empirical formula of M?

    • CH2N 

    • C4HN4

    • CH4N

    • C2H4N

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