Chemistry Activity 1.7 Quiz

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Questions and Answers

What is the chemical formula for the gas emitted when lead nitrate is heated?

NO2 (correct)

N2O

What is the name of the process used in Activity 1.7 to decompose water?

Filtration

Sublimation

Distillation

Electrolysis (correct)

Which of the following is NOT a product of the decomposition of lead nitrate?

Lead oxide (PbO)

Nitric acid (HNO3) (correct)

Nitrogen dioxide (NO2)

Oxygen (O2)

What is the purpose of the carbon electrodes in Activity 1.7?

To provide a pathway for the flow of electricity (A) Signup and view all the answers

Why is it important to add dilute sulphuric acid to the water in Activity 1.7?

To increase the conductivity of the water (C) Signup and view all the answers

What observation would indicate that a burning candle is being extinguished by the gas collected in one of the test tubes in Activity 1.7?

The candle flame goes out (B) Signup and view all the answers

Which of the following statements accurately describes the volume of gas collected in each test tube in Activity 1.7?

The volume of gas collected in one test tube is twice the volume collected in the other (D) Signup and view all the answers

What is the purpose of the rubber stoppers in the holes of the plastic mug in Activity 1.7?

To hold the electrodes in place (D) Signup and view all the answers

What happens to the magnesium ribbon when it is burned?

It transforms into magnesium oxide. (A) Signup and view all the answers

Which of the following scenarios is an example of a chemical change?

Cooking food. (D) Signup and view all the answers

What is produced when magnesium reacts with oxygen?

Magnesium oxide. (A) Signup and view all the answers

Which activity illustrates a change in the identity of a substance due to a chemical reaction?

Fermenting grapes. (D) Signup and view all the answers

In which condition do chemical reactions typically occur?

Under various temperatures and pressures. (D) Signup and view all the answers

What could be an observation of magnesium ribbon burning in air?

It burns with a dazzling white flame. (D) Signup and view all the answers

Which statement best describes a physical change?

It involves a change of state without altering composition. (D) Signup and view all the answers

Which of the following is a common indicator of a chemical reaction?

Formation of a gas. (B) Signup and view all the answers

What is the final balanced equation after all steps?

3 Fe + 4 H2O → Fe3O4 + 4 H2 (A) Signup and view all the answers

Which element was the last to be balanced in the equation?

Iron (D) Signup and view all the answers

What does the hit-and-trial method involve when balancing equations?

Balancing only one element at a time (A) Signup and view all the answers

What notation indicates a substance in a gaseous state in a chemical equation?

(g) (B) Signup and view all the answers

Why is it important to include physical states in a balanced equation?

To communicate the properties of reactants and products (B) Signup and view all the answers

In the balanced equation 3Fe(s) + 4H2O(g) → Fe3O4(s) + 4H2(g), what does the (g) next to H2O signify?

Water is present as steam (C) Signup and view all the answers

How many hydrogen atoms are present in the reactants of the balanced equation?

8 (A) Signup and view all the answers

What will be the number of iron atoms on the left-hand side of the equation after balancing?

3 (A) Signup and view all the answers

Why are physical states usually not included in chemical equations?

They are only needed when specified (A) Signup and view all the answers

What color change occurs to the copper sulphate solution after the iron nails are immersed?

It loses its blue color (A) Signup and view all the answers

What are the coefficients used for balancing the equation?

3 for Fe and 4 for H2O (C) Signup and view all the answers

What represents an aqueous state of a substance in chemical reactions?

(aq) (B) Signup and view all the answers

What happens to the iron nail when placed in copper sulphate solution?

It becomes brownish (C) Signup and view all the answers

In a chemical equation, what does the notation above and below the arrow typically indicate?

Reaction conditions like temperature and pressure (C) Signup and view all the answers

What is the main outcome of balancing a chemical equation?

To create equal numbers of atoms of each element on both sides (C) Signup and view all the answers

Which of the following reactions shows the formation of an insoluble product?

Barium chloride + Aluminium sulphate → Barium sulphate + Aluminium chloride (B) Signup and view all the answers

In the reaction between iron and copper sulphate, which substance is displaced?

Copper (A) Signup and view all the answers

What is the state symbol for liquid water in a chemical equation?

(l) (D) Signup and view all the answers

What type of reaction occurs when iron displaces copper from copper sulphate solution?

Displacement reaction (A) Signup and view all the answers

Which of the following elements is more reactive than copper and can displace it?

Zinc (A) Signup and view all the answers

What is produced when sodium reacts with water?

Sodium hydroxide and Hydrogen (D) Signup and view all the answers

What is the formula for iron sulphate produced in the reaction?

FeSO4 (B) Signup and view all the answers

After the reaction, what happens to the copper in the solution?

It precipitates out as solid copper (B) Signup and view all the answers

In the reaction Fe(s) + CuSO4(aq) → FeSO4(aq) + Cu(s), which substances are reactants?

Fe and CuSO4 (C) Signup and view all the answers

What gases are produced when potassium metal reacts with water?

Potassium hydroxide and hydrogen (B) Signup and view all the answers

What type of reaction occurs when barium chloride reacts with potassium sulfate?

Precipitation reaction (B) Signup and view all the answers

Which equation represents a decomposition reaction?

Zinc carbonate(s) → Zinc oxide(s) + Carbon dioxide(g) (D) Signup and view all the answers

What defines an exothermic reaction?

It releases thermal energy. (D) Signup and view all the answers

What type of reaction is represented by the equation: Hydrogen(g) + Chlorine(g) → Hydrogen chloride(g)?

Combination reaction (A) Signup and view all the answers

Which reaction is an example of a double displacement reaction?

Barium chloride + Potassium sulfate → Barium sulfate + Potassium chloride (B) Signup and view all the answers

In which scenario does reduction occur?

Gain of hydrogen (A) Signup and view all the answers

What products are formed when hydrogen sulfide gas burns in air?

Water and sulfur dioxide (A) Signup and view all the answers

Study Notes

Chemical Reactions and Equations

Chemical reactions involve changes in the nature and identity of substances.
Chemical reactions involve changes in state, color, formation of gas, and changes in temperature.
A chemical reaction occurs when chemical bonds are broken and new chemical bonds are formed.
A chemical reaction is represented by a chemical equation.
Chemical equations represent reactions concisely, using chemical formulas instead of words.
In a chemical equation, reactants appear on the left side and products on the right side, separated by an arrow.
Chemical equations must be balanced, meaning the same number of atoms of each element are on both sides of the equation. This follows the law of conservation of mass.
Different types of chemical reactions include combination, decomposition, displacement, and double displacement reactions.

Activity 1.1: Magnesium in Air

This activity demonstrates a chemical reaction: magnesium burning in air.
A magnesium ribbon is cleaned using sandpaper, then held with tongs and burned with a spirit lamp or burner.
Ash is collected in a watch glass.
Observation: magnesium ribbon burns with a dazzling white flame and forms a white powder (magnesium oxide).

Activity 1.2: Lead Nitrate and Potassium Iodide

This activity demonstrates a reaction resulting in a precipitate (a solid that forms from a solution).
Lead nitrate solution is added to potassium iodide solution.
Observation: a yellow precipitate forms.

Activity 1.3: Zinc and Hydrochloric Acid

This activity demonstrates a chemical reaction producing a gas.
Zinc granules are added to hydrochloric or sulfuric acid.
Observation: bubbles form, and the test tube or flask warms up.

1.1 Chemical Equations

Chemical equations concisely represent chemical changes.
Reactants are the starting substances; products are the resulting substances.
Word equations show the reaction using words.
Chemical equations show the change in formulas.

1.1.1 Writing a Chemical Equation

Chemical equations use chemical formulas instead of words.
The number of atoms of each element must be balanced.

1.1.2 Balanced Chemical Equations

The law of conservation of mass dictates that the total mass of reactants equals the total mass of products.
Balanced equations have equal numbers of atoms of each element on both sides.

Activity 1.4: Calcium Oxide and Water

Calcium oxide (quicklime) reacts vigorously with water to produce calcium hydroxide (slaked lime).
The reaction releases significant heat, making it an exothermic process.

1.2 Types of Chemical Reactions

Combination Reactions: Two or more reactants form a single product.
Decomposition Reactions: A single reactant breaks down into two or more products.
Displacement Reactions: More reactive element displaces a less reactive element from a compound.
Double Displacement Reactions: A reaction where ions exchange places between two compounds. This often results in the formation of a precipitate.

Activity 1.5: Ferrous Sulphate Decomposition

Ferrous sulphate crystals decompose into ferric oxide, sulphur dioxide, sulphur trioxide, and gaseous water when heated.
Observation: color change and odour production.

Activity 1.6: Lead Nitrate Decomposition

Lead nitrate decomposes into lead oxide, nitrogen dioxide, and oxygen when heated.
Observation: emission of brown fumes, color change.

Activity 1.7: Electrolysis of Water

Electrolysis is a technique of using a direct electric current to drive a non-spontaneous chemical reaction.
Water is split into hydrogen and oxygen using an electric current.

Activity 1.8: Silver Chloride in Sunlight

Silver chloride decomposes into silver and chlorine in sunlight.
Observation: silver chloride turns gray.

Activity 1.9: Iron and Copper Sulphate

Iron displaces copper from copper sulphate solution.
Observation: the color of copper sulphate solution changes, and iron nails become coated with copper.

Activity 1.10: Double Displacement

Sodium sulphate and barium chloride solutions react, forming insoluble barium sulphate precipitate.

1.2.5 Oxidation and Reduction

Oxidation: gain of oxygen or loss of hydrogen.
Reduction: loss of oxygen or gain of hydrogen
Reactions involving simultaneous oxidation and reduction are called redox reactions.

Questions

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Description

Test your knowledge on the chemical principles involved in Activity 1.7. This quiz covers the decomposition of lead nitrate, the reactions with water, and the roles of different components in the experiment. Prepare to deepen your understanding of these important chemistry concepts!