S2M2 - Science 9

Abbas investigates the reaction of zinc with hydrochloric acid. He pours 25 cubic centimeters of the acid into a conical flask. He adds small pieces of zinc. He collects the gas in a syringe.

What gas is produced and trapped in the syringe?

• oxygen

• carbon dioxide

• hydrogen

• nitrogen

Nico made an experiment where he added metal to an acid. He recorded the amount of gas produced.

He plots a graph of his results.

Between which times is the reaction fastest?

• between 0 and 1 minute

• between 2 and 3 minutes

• between 3 and 4 minutes

• there is no enough evidence

Vika wanted to find out how the rate of reaction changes if he increases the concentration of acid that would react to metal.

Which two variables he should keep the same in his investigation?

• the amount of light and time of chemical reaction between an acid and metal

• the temperature of the acid and the surface area of the metal

• the amount of catalyst and the amount of an acid

• the temperature of catalyst and the amount of light exposed to the reaction.

Arifa investigates the reaction of sodium thiosulfate solution with hydrochloric acid.

One of the products of the reaction is sulfur. This forms as a solid.

As sulfur is made, it hides the cross under the conical flask. Arifa measures the times taken for the cross to disappear.

Arifa wants to find out how changing the temperature affects the rate of the reaction.

Name the variable Arifa measures.

• temperature

• time of reaction

• concentration of the acid

• amount of substanace

Arifa made an investigation on the reaction of sodium thiosulfate solution with hydrochloric acid.

Arifa recorded the results in the table below.

Find the missing average.

• 200

• 201

• 202

• 203

Amanda investigates the reaction of hydrochloric acid with calcium carbonate.

The equation for the reaction is:

hydrochloric acid + calcium carbonate --> calcium chloride + carbon dioxide + water

Predict which product of the reaction is formed as a gas

• Oxygen

• Nitrogen

• Carbon Dioxide

• Water Vapor

Amanda set up the apparatus below to test whether or not the gas will produce when an acid reacts with a carbonate compound.

Amanda predicts that, as the reaction progresses, the mass of the reaction mixture in the flask will decrease.

Which of the reasons below best explains why the mass decreases?

• the product that is formed as a gas dissolved in the reaction mixture

• the product that is formed as a gas escapes into the air

• the product that is formed as a gas is made up of atoms of two elements.

• the product that is formed as a gas in an invisible gas.

Amanda records the mass of the reactant mixture (metal and acid) every minute. She plots a graph of his results.

Predict which of the graphs below best represents Rashid's results.

• A

• B

• C

Amanda wants to investigate how the size of the pieces of calcium carbonate affects the reaction rate.

She has three sizes of calcium carbonate pieces - big lumps, small lumps, and powder.

She decides to measure the time taken for 1.0 g of gas to be made with each size of calcium carbonate piece.

Name the variable she changes.

• type of acid used

• amount of metal used

• surface area of calcium carbonate

• time of the reaction

Amanda finds that the powder reacts most quickly.

Which of the reasons below best explains why?

• for a certain mass of calcium carbonate, the powder has the smallest surface area

• for a certain mass of calcium carbonate, the powder has the biggest surface area

• for a certain mass of calcium carbonate, the powder has the highest concentration

• all of the above