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ASSIGNMENT
( for use of lecturer: summit on time yes / no )
NAME: ____________________________________
SECTION: ________
IC NO: ___________________________
LECTURER’S NAME: _________________________________________
Answer all questions in the space provided and working must be shown clearly.
1. Calculate the average atomic mass for nickel, there are five isotopes as given in the table.
isotope
mass (amu)
abundance
58Ni
57.9354
67.76%
60Ni
59.9308
26.16%
61Ni
60.9311
1.25%
62Ni
61.9283
3.66%
64Ni
63.9280
1.16%
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2. What is the percent of Cd, S and O in the compound CdSO4
3. The percent composition by mass of an unknown chlorinated hydrocarbon was found to be
37.83% C, 6.35% H, and 55.83% Cl by mass. What is the empirical formula of this compound?
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4. The percent composition by mass of tartaric acid is: 32.01% C, 4.03% H, and 63.96% O. Given
that the molar mass of tartaric acid is 150 g/mol, determine its molecular formula.
5. Silicon tetrachloride (SiCl4) can be prepared by heating Si in chlorine gas:
Si (s)
+
Cl2 (g) →
SiCl4 (l)
In one reaction, 0.507 mole of SiCl4 is produced. How many moles and grams of chlorine gas
were used in the reaction?