Form 4 - Chemistry

The diagram above shows a graph of sodium chloride solubility against the temperature of the water.

Which of the following statements is correct?

• Temperature is the responding variable.

• Solubility is not affected by the temperature.

• The amount of sodium chloride is the manipulated variable in the experiment.

• Increasing the temperature will increase the amount of sodium chloride dissolved.

What is the manipulated variable based on the statement below?

• Temperature

• Rate of reaction

• Substance X

• Volume

The following shows a statement by a teacher.

Which of the following is correct when conducting an experiment to prove the above statement?

• Manipulated variable: Presence of water

  Constant variable: Presence of air

• Manipulated variable: Absence of water

  Constant variable: Absence of air

• Manipulated variable: Presence of air

  Constant variable: Presence of water

• Manipulated variable: Absence of air

  Constant variable: Absence of water

Haris wants to investigate how X is affected by factor Y.

What variables are X and Y?

• X: Manipulated variable
  Y: Constant variable

• X: Responding variable
  Y: Constant variable

• X: Constant variable
  Y: Responding variable

• X: Responding variable
  Y: Manipulated variable

Which of the following experimental procedures is correct?

• Preparing bromine water in a fume cupboard.

• Recording experimental results after the experiment has been completed.

• Filling a pipette by sucking with the mouth.

• Feeling excited to do an experiment.

The diagram above shows the cooling curve of naphthalene.

Which of the following statements are correct about the process that occurs at point Q?

I The kinetic energy of the molecules decreases.

II Naphthalene is in the liquid state.

III Naphthelene loses heat to the environment.

IV Naphthalene has completely solidified.

• I and II

• I and III

• II and IV

• III and IV

Atom  $Y$  has 7 proton numbers and 14 nucleon numbers.

What is the electron arrangement of  $Y^{3-}$  ?

• 2.5

• 2.8

• 2.8.4

• 2.8.8

Which of the following statements are correct?

I The nucleon number is always greater than the proton number of the same element.

II An element has only one proton number.

III Ions do not have correct proton numbers or nucleon numbers.

IV The proton number of an element can be equal to its nucleon number.

• I and II

• I and III

• II and IV

• III and IV

What are the characteristics of isotopes of the same elements?

I Have different chemical properties

II have different physical properties

III Have same physical properties

IV Have the same electron arrangement

• I and II

• I and III

• II and IV

• III and IV

The proton number of element  $Z$  is 15.

How many valence electrons does element  $Z$  have?

• 4

• 5

• 6

• 7