Molecular Mass

Author:NCERT
9th CBSE
IMPORTANT

Important Questions on Molecular Mass

EASY
IMPORTANT

Which of the following molecules is triatomic?

EASY
IMPORTANT

In which of these elements is the mass of 1 mole atom equal to the mass of 1 mole molecule?

EASY
IMPORTANT

The atomic mass of four elements are given below:

  Carbon Helium Calcium Nitrogen
Atomic Mass (u) 12 4 40 14

Molar mass is the mass of 1 mole of an element or a compound. Which element has the highest molar mass?

MEDIUM
IMPORTANT

Calculate the masses of sugar and water required to prepare 200g of 15% mass by mass of solution of sugar in water.

HARD
IMPORTANT

Which of the following statement is incorrect?

HARD
IMPORTANT

Which of the following has the smallest mass?

MEDIUM
IMPORTANT

A complex of iron contains 45.6% iron by mass. Find out the number of iron atoms in 5.00 g of this complex

HARD
IMPORTANT

A student wants to have 3.011×1023 atoms each of magnesium and carbon elements. For this purpose, how much magnesium and carbon will he weigh in grams? 

HARD
IMPORTANT

The ratio of moles of atoms in 12 g of magnesium and 16 g of sulphur will be:

MEDIUM
IMPORTANT

How many O2 molecules are there in one mole of oxygen gas?

HARD
IMPORTANT

The mass of one atom of chlorine is _____×10-23gms. Avogadro number is 6.023×1023.

(Write the value with four significant figures)

HARD
IMPORTANT

Which of the following correctly represents 360 g of water?

 i 2 moles of H2O

 ii 20 moles of water

iii 6.022 × 1023 molecules of water

iv 1.2044 × 1025 molecules of water

HARD
IMPORTANT

The molar mass of H2O is 18 g/mol. What is the number of moles in 90 g water? 

MEDIUM
IMPORTANT

The number of moles in 36 grams of water (H2O) is _____. (one / two / three)

HARD
IMPORTANT

Which of the following has maximum number of atoms?

HARD
IMPORTANT

The formula of ethanol is C2H5-OH. Its molecular mass is

HARD
IMPORTANT

Buckminsterfullerene is an allotrope of carbon in which atoms of carbon form pentagonal and hexagonal rings which are joined together to form a football-like round structure. Its molecular formula is C60. The molar mass of buckminsterfullerene and the number of atoms in one gram molecule of it are:

HARD
IMPORTANT

The mass of one atom of oxygen is _____ ×10-23 g.(2.657/0.265)

MEDIUM
IMPORTANT

The number of atoms present in 64 g of S8  is 12.04×1023.