Speeds of Reactions

According to the collision theory, which statement does not result in a chemical reaction?

• Reacting particles must collide with one another.
• Reacting particles must be oriented properly.
• Reacting particles must possess a minimum energy, known as activation energy, before reaction can take place.
• Frequency of effective collisions increase.

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NGSS.HS-PS1-5

In terms of particulate theory, why do smaller pieces of solid react more quickly with liquid reactant than an equal mass of larger pieces of solid?

• There are stronger forces between the solid and the colliding particles.
• The solid has a larger surface area for particles of the liquid to collide with.
• The particles of the liquid collide with each other more frequently.
• The particles of liquid do not have to break so many bonds in the solid.

Tags

NGSS.HS-PS1-5

Which is not a suitable method to investigate the rate of reaction between hydrochloric acid and magnesium?

• Measure the time taken for all the magnesium to completely react.
• Measure the volume of hydrogen gas collected at regular time intervals.
• Measure the mass of reaction mixture at regular time intervals.

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NGSS.HS-PS1-5

An experiment with a reaction mixture of carbonate and acid in a container was placed on an electronic balance. The mass of reactants and container was measured at regular time intervals. A graph of the mass reading against time was plotted. Which curve was obtained?

• A
• B
• C
• D

Zinc reacts with hydrochloric acid.  Which solution would give the fastest initial rate of reaction? 

• 80 g of HCl in 1000 cm³ of water
• 40 g of HCl in 1000 cm³ of water
• 20 g of HCl in 100 cm³ of water
• 16 g of HCl in 100 cm³ of water

Tags

NGSS.HS-PS1-5

If a strip of magnesium is dropped into excess hydrochloric acid an exothermic reaction occurs. The rate of reaction increases during the first few seconds because

• the amount of magnesium is decreasing.
• the magnesium is acting as a catalyst.
• the solution is becoming hotter. 
• the surface area of magnesium is increasing. 

Tags

NGSS.HS-PS1-5

In a reaction between excess copper(II) carbonate and sulfuric acid, the maximum amount of carbon dioxide is collected in a gas syringe. Which statement is not true? 

• The mass of copper(II) carbonate decreases to zero.
• The amount of carbon dioxide collected depends on the limiting reactant. 
• Sulfuric acid is used up in the reaction. 
• The speed decreases because concentration of sulfuric acid decreases. 

Tags

NGSS.HS-PS1-5

In which reaction is the pressure not likely to affect the rate of reaction?

• H₂SO₄(aq) + 2NaOH(aq) → Na₂SO₄(aq)  +  2H₂O(l)
• CuO(s)  +  H₂(g) → Cu(s) + H₂O(l)
• 3H₂(g) + N₂(g) → 2NH₃(g)
• Fe₂O₃(s) + 3CO(g) → 2Fe(s) + 3CO₂(g)

Tags

NGSS.HS-PS1-5

In the reaction between strips of zinc and 1.0 mol/dm³ hydrochloric acid, what changes would increase the speed of reaction? (choose more than one answer)

• use powdered zinc

• use 2.0 mol/dm³ hydrochloric acid

• conduct experiment at a higher pressure

• increase the temperature of the acid by 10^oC

Tags

NGSS.HS-PS1-5

What is true of the diagram?

(You may choose one or more answers)

• As temperature increases, the number of particles with the minimum activation energy increases.

• As temperature increases, the particles gain greater activation energy.

• The total number of particles is represented by the area under the curve.

• With a catalyst, the curve shown would be the same as the original curve.

Tags

NGSS.HS-PS1-5