Forum

Atoms and molecules

When 3.0 g of carbon is burnt in 8.00 g oxygen, 11.00 g of
carbon dioxide is produced. What mass of carbon dioxide will
be formed when 3.00 g of carbon is burnt in 50.00 g of
oxygen? Which law of chemical combination will govern your
answer?

09/11/2024

Science

9th

Atoms and molecules

 A 0.24 g sample of compound of oxygen and boron was found
by analysis to contain 0.096 g of boron and 0.144 g of oxygen.
Calculate the percentage composition of the compound by
weight.

09/11/2024

Science

9th

Atoms and molecules

Calculate the formula unit
masses of ZnO, Na2O, K2CO3,
given atomic masses of Zn = 65 u,
Na = 23 u, K = 39 u, C = 12 u,
and O = 16 u.

09/11/2024

Science

9th

Atoms and molecules

Calculate the molecular masses
of H2
, O2
, Cl2
, CO2
CH4
C2H6,
C2H4
, NH3
, CH3OH.

09/11/2024

Science

9th

Atoms and molecules

How many atoms are present in a
(i) H2S molecule and
(ii) PO43– ion?
compounds represented by the_________

09/11/2024

Science

9th

Atoms and molecules

What is meant by the term
chemical formula?

09/11/2024

Science

9th

Atoms and molecules

Write down the names of following formulae:
(i) Al2(SO4)3
(ii) CaCl2
(iii) K2SO4
(iv) KNO3
(v) CaCO3

09/11/2024

Science

9th

Atoms and molecules

Write down the formulae of
(i) sodium oxide
(ii) aluminium chloride
(iii) sodium sulphide
(iv) magnesium hydroxide

09/11/2024

Science

9th

Atoms and molecules

Why is it not possible to see an
atom with naked eyes?

09/11/2024

Science

9th

Atoms and molecules

Define the atomic mass unit.

09/11/2024

Science

9th