#### 1. How many molecules are in 15.0 g of PH_{3}?

(Avogadro’s number is 6.022 x 10^{23})

Correct!
Wrong!

#### 2. What is the molar mass of an oxygen atom?

Correct!
Wrong!

#### 3. The density of pure water is 1000 g dm^{-3}.

What is the molarity of pure water?

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Wrong!

#### 4. Calculate the mass of KOH that should be dissolved in 500 cm^{3} water to give a solution with a concentration of 0.600 mol dm^{-3}

Correct!
Wrong!

#### 5. A 1 dm^{3} sample of Noble gas X contains 0.04471 moles. The density of the gas is 1.784 g dm^{-3}.

Which gas does the sample contain?

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#### 6. Calculate the concentration of the solution that is formed by adding 50 cm^{3} of water to 25 cm^{3} of 0.268 mol dm^{-3} HCl

Correct!
Wrong!

#### 7. 0.05 moles of an Iron salt FeCl_{x} reacts with AgNO_{3}to form 21.5 g of AgCl. What is the value of x?

Correct!
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#### 8. A The uncertainty of a balance is + 0.1g.

What is the % uncertainty if this balance is used to measure 26.7 g of CuSO_{4}?

Correct!
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#### 9. What is the formula of Iron(II) Carbonate?

Correct!
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#### 10. Dinitrogen Monoxide decomposes to produce Nitrogen and Oxygen according to the following equation:

2N_{2}O(g) → 2N^{2}(g) + O_{2}(g)

Assuming a constant temperature, how many times greater is the volume of the products than the volume of the reactants?

Correct!
Wrong!