Chemistry_0620_1_OCT 2020

A mixture of ice and water is left to stand and the ice melts. Which row describes what happens as the ice is melting?

• A

• B

• C

• D

Which piece of apparatus is used to measure 25.0 cm³ of aqueous sodium hydroxide?

• A

• B

• C

• D

Paper chromatography is used to determine the R_f values for four different food colourings. Which food colouring has an R_f value of 0.6?

• A

• B

• C

• D

The diagram shows the electronic structure of a particle with a nucleon number (mass number) of 40. The table shows the suggestions that three students, 1, 2 and 3, made to identify the particle. Which students are correct?

• 1 and 2 only

• 1 and 3 only

• 2 and 3 only

• 1, 2 and 3

The electronic structures of two atoms, P and Q, are shown.

• A

• B

• C

• D

Which statement about the structure of a metal explains why metals are malleable?

• The electrons can move freely throughout the lattice.

• The layers of metal ions can slide over each other.

• The metal ions are positively charged.

• There is a strong force of attraction between the metal ions and the electrons.

The bonding, structure and melting point of sodium chloride and sulfur dichloride are shown. Why does sulfur dichloride have a lower melting point than sodium chloride?

• The covalent bonds in sulfur dichloride are weaker than the attractive forces between molecules in sodium chloride.

• The covalent bonds in sulfur dichloride are weaker than the ionic bonds in sodium chloride.

• The attractive forces between molecules in sulfur dichloride are weaker than the attractive forces between molecules in sodium chloride.

• The attractive forces between molecules in sulfur dichloride are weaker than the ionic bonds in sodium chloride.

Lead(II) nitrate, Pb(NO₃)₂, reacts with potassium iodide, KI, to form a yellow precipitate, PbI₂, and a soluble salt, KNO₃. What is the equation for the reaction?

• Pb(NO₃)₂ + KI → PbI₂ + KNO₃

• Pb(NO₃)₂ + 2KI → PbI₂ + KNO₃

• 2Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃

• Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃

Which diagram represents a chemical change?

• A

• B

• C

• D

Which diagram shows a mixture of noble gases?

• A

• B

• C

• D