1. Balance the following equation with the smallest whole number coefficients possible. What is the number that is the sum of the coefficients?

   KClO₃ -> KCl + O₂

• 3

• 5

• 6

• 7

Calculate the mass of hydrogen formed when 27 g of aluminum reacts with excess hydrochloric acid according to the balanced equation below.

2Al + 6HCl -> 2AlCl₃ + 3H₂

• 1.5 g

• 2.0 g

• 3.0 g

• 6.0 g

How many grams of nitric acid, HNO₃ , can be prepared from the reaction of 138 g of NO₂ with 54.0 g H₂O according to the equation below? (unbalanced equation)

NO₂ + H₂O -> HNO₃ + NO

• 92

• 108

• 126

• 189

What is the most specific characterization of the reaction shown?

Ca(OH)₂ (aq) + H₂SO₄ (aq) -> CaSO₄ (aq) + H₂O (l)

• Single-displacement

• Neutralization

• Double displacement

• Combustion

In the reaction between Na₂S and AgNO₃ (Double displacement reaction), if 39.05 g of Na₂S are reacted with 85.5 g of AgNO₃ . How much of the excess reagent will be left over once the reaction has gone to completion?

• 19.5 g Na₂S

• 26.0 g Na₂S

• 41.4 g AgNO₃

• 74.3 g AgNO₃

The reaction of 7.8 g benzene, C₆H₆, with excess HNO₃ resulted in 0.90 g of H₂O and unknown amount of C₆H₅NO₂. What is the percentage yield of water?

• 100%

• 50%

• 25%

• 12%

7. What is the concentration in mol/dm³ of 46.5 g NaNO₃ in 200 cm³ solution?

• 2.735 M

• 0.547 M

• 4.65 M

• 1.35 M

What is the volume of 0.2 M HCl required to neutralise 0.3 M NaOH 10 cm³ ?

• 10 mL

• 15 mL

• 20 mL

• 25 mL

Calculate the volume of H₂ gas produced at 25 ⁰C, when the magnesium ribbon 0.24 g. reacted with hydrochloric (HCl) in excess.

• 0.24 cm³

• 24 cm³

• 0.24 dm³

• 24 dm³

Which one of these statements has highest number of mole?

• Glucose (C₆H₁₂O₆) 180 g.

• NaCl 1.20 x 10²⁴ molecules

• N₂ 40,000 cm³ in RTP

• NaOH 0.2 M 300 cm³ solution