Form 4 Chapter 3 Mole, Chemical Formula and Equation

6.02 x 10 ^23 of molecule atoms in hydrogen gas equal to 1 mole.

Is the above statement is true?

• True

• False

Empirical formula is a formula which gives the actual number of atoms of each element present in a compound.

Is the statement about empirical formula is true?

• True

• False

Is this chemical equation balanced ?

• Yes

• No

What is the meaning of Avogadro constant, N_A?

• 
  Volume occupied by one mole of gas

• Mass of one mole of a substance

• Number of particles in one mole of a substance

• Pressure of one mole of a substance

Why carbon-12 was chosen as a reference standard for relative atomic mass, RAM?

• Carbon is a solid and easier to be handled

• Carbon is located in Group 14 in the Periodic Table of Elements

• Carbon has three isotopes

• Carbon is a nonmetal element

Which of the following compounds and formula is correct?

• A
• B
• C
• D

Diagram below shows the set-up of apparatus for an experiment to determine the empirical formula of magnesium oxide. Why is the crucible lid opened occasionally during the heating?

• To avoid explosion
• To allow oxygen gas to enter the crucible
• To cool the magnesium
• To see what happen inside the crucible

 What is the molar mass of Mn(NO3)2 ?

• 188

• 179

• 139

• 122

Diagram below shows an observation when a cockle shell is put into a beaker containing vinegar. What is X?

• Oxygen
• Sulfur dioxide
• Carbon dioxide
• Hydrogen

The relative molecular mass of compound with empirical of CH2 is 42.

• CH2
• C2H4
• C3H6
• C4H8