Phiếu bài tập Hóa học cho kỳ thi đầu vào điều dưỡng có đáp án

What does the double arrow (⇌) in a chemical equation show?

1. AThe reaction releases heat
2. BThe reaction needs a catalyst
3. CThe reaction is very fast
4. DThe reaction is reversible

How does increasing the concentration of a reactant in solution usually affect the reaction rate?

1. AThe rate decreases
2. BThe reaction stops
3. CThe rate increases
4. DThe rate stays the same

Standard atmospheric pressure (1 atm) is equal to how many millimetres of mercury?

1. A100 mmHg
2. B120 mmHg
3. C760 mmHg
4. D1000 mmHg

In the balanced equation __Mg + __HCl → __MgCl₂ + __H₂, what is the coefficient of HCl?

1. A1
2. B2
3. C3
4. D4

How many oxygen atoms are in one formula unit of calcium nitrate, Ca(NO₃)₂?

1. A3
2. B2
3. C6
4. D5

Why is a carbon dioxide extinguisher effective on many fires?

1. ACO₂ adds oxygen to cool the flames
2. BCO₂ is a liquid that soaks into the fuel
3. CCO₂ reacts chemically with the fuel to make it non-flammable
4. DCO₂ is denser than air and pushes oxygen away from the fire

Marble chips react with hydrochloric acid, giving off CO₂. The gas is produced quickly at first, then more and more slowly. Why does the rate fall?

1. AThe CO₂ produced turns back into acid
2. BThe acid concentration falls as it is used up, so collisions become less frequent
3. CThe activation energy steadily increases as the reaction goes on
4. DThe products act as a catalyst that slows the reaction down

Trong phản ứng CuO + H₂ → Cu + H₂O, chất nào bị khử?

1. AHydrogen, vì nó nhận oxygen
2. BĐồng, vì nó mất electron
3. CĐồng oxide, vì đồng nhận electron
4. DNước, vì nó được tạo thành