Chapter 3 quiz

The proton number of sodium atom is 11 and its molar mass is 23 gmol^-1. What is the relative atomic mass of sodium atom?

• 11

• 12

• 23

• 24

What is the relative molecular mass of hydrated magnesium sulphate, MgSO₄.7H₂O? [relative atomic mass: Mg=24; S=32; O=16; H=1]

• 145

• 246

• 305

• 356

The relative formula mass of hydrated X carbonate, X₂CO₃.10H₂O is 286. What is the relative atomic mass of element X? [relative atomic mass: H=1; C=12; O=16]

• 23

• 46

• 32

• 64

A balloon contains  $6.02\times10^{23}$ of gas particle. What is the number of moles of the gas in the balloon? 

• 0.5 mol

• 1.0 mol

• 3.0 mol

• 6.0 mol

What is the number of moles of copper (II) nitrate in 56.4g of copper (II) nitrate, Cu(NO₃)₂? [relative atomic mass: O=16; Cu=64; N=14]

• 0.30 mol

• 0.32 mol

• 0.33 mol

• 0.03 mol

The formula of a carbonate ion is CO₃^2- and for nitrate ion is NO₃^-. If the formula of the carbonate salt of X is XCO₃, what is the formula of the nitrate salt of X?

• XNO₃

• X₂NO₃

• X(NO₃)₂

• X(NO₄)₃

Potassium dichromate is one of the potassium salt with a bright red-orange colour. It is widely used in various industries such as in the manufacture of paint. Choose the correct chemical formula of potassium dichromate.

• KCrO₄

• K₂Cr₂O₇

• K₂CrO₄

• KCr₂O₇

C₆H₁₂O₆ is the molecular formula of glucose. What is its empirical formula?

• C₂H₂O₂

• CH₂O₂

• C₂H₄O₂

• CH₂O

What is the meaning of empirical formula?

• Formula that shows the actual number of atoms of each element in the compound

• Formula that shows the simplest ratio of atoms of each element in the compound

• Formula that shows how the atoms of elements are bonded together

• Formula that shows the type of element in the compound

C₆H₁₂O₆ is the molecular formula of glucose. Which of the following substance has similar empirical formula as that of glucose?

• Ethanol, C₂H₆O

• Methanol, CH₄O

• Ethanoic acid, C₂H₄O₂

• Methyl ethanoate, C₃H₆O₂