$A$ silver ornament of mass $m \, g$ is polished with gold equivalent to $1\%$ of the mass of silver. Compute the ratio of the number of atoms of gold and silver in the ornament.

Which of the following contains the maximum number of molecules?

The symbols of calcium,carbon,and copper are

$(a)$ $A$ sample of vitamin $C$ is known to contain $2.58 \times 10^{24}$ oxygen atoms. How many moles of oxygen atoms are present in the sample?
$(b)$ Write one word for the following:
$(i)$ In a balanced chemical equation,the sum of the masses of reactants and products remains unchanged.
$(ii)$ $A$ group of atoms carrying a fixed charge on them.
$(c)$ Write chemical formulae of the following compounds:
$(i)$ Sodium phosphate
$(ii)$ Ammonium carbonate

Write the chemical formulae for the following compounds and find the ratio by mass of the combining elements in each one of them.
$(N=14 \ u, H=1 \ u, C=12 \ u, O=16 \ u, S=32 \ u)$
$(a)$ Methane
$(b)$ Carbon dioxide
$(c)$ Hydrogen sulphide

The chemical symbol for sodium is