SOME BASIC CONCEPTS OF CHEMISTRY

Front

Number of significant figures in 12.6 X 11.2 are:

Back

3

Front

A jug contains 2 L of milk. The volume of milk in m³ is:

Back

0.002

Front

Mass of 100 molecules of sucrose (C₁₂H₂₂O₁₁)? Options: 100 g, 342 g, 3.88 × 10^–20 g, 5.68 × 10^–20 g

Back

5.68 × 10^–20 g

Front

Number of atoms in 52 g of He are:

Back

7.83 X 10²⁴

Front

A compound contains 4.07% hydrogen, 24.27% carbon and 71.65% chlorine. Its molecular mass is 98.96. Its empirical formula is: C₂H₂Cl₂, CHCl, CHCl₂, CH₂Cl

Back

CH₂Cl

Front

How many moles of methane are required to produce 22g of CO₂(g) after combustion?

Back

0.5 Moles

Front

The molality of a solution containing 20.7 g of potassium carbonate dissolved in 500 mL of solution (assume density of solution =1 g mL^–1). Options: 3.13 m, 0.313 m, 31.3 m, None of the above.

Back

0.313 m

Front

Which of the following statement is INCORRECT?

• protium has no neutron
• C14 is used for finding age of old wooden objects
• Ca-40 and Ar-50 are isotopes
• Ca-40 and Ar-40 are isobars

Back

Ca-40 and Ar-50 are isotopes

Front

Which element contains the greatest number of atoms? Options: 4g He, 46g Na, 0.4g Ca, 12g He

Back

12g He

Front

Empirical formula: CH2O, Molecular mass: 180 g. What is the molecular formula? Options: C2H4O2, HCHO, C6H12O6, CH3COOH.

Back

C6H12O6