Write the chemical formulae for the following substances and calculate the molecular mass for each one of them:
$(a)$ Caustic potash
$(b)$ Baking soda
$(c)$ Limestone
$(d)$ Caustic soda
$(e)$ Ethanol
$(f)$ Common salt

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(N/A) Caustic potash: $KOH$
Molecular mass: $39 + 16 + 1 = 56 \, g \, mol^{-1}$
$(b)$ Baking soda: $NaHCO_3$
Molecular mass: $23 + 1 + 12 + (3 \times 16) = 84 \, g \, mol^{-1}$
$(c)$ Limestone: $CaCO_3$
Molecular mass: $40 + 12 + (3 \times 16) = 100 \, g \, mol^{-1}$
$(d)$ Caustic soda: $NaOH$
Molecular mass: $23 + 16 + 1 = 40 \, g \, mol^{-1}$
$(e)$ Ethanol: $C_2H_5OH$
Molecular mass: $(2 \times 12) + (6 \times 1) + 16 = 46 \, g \, mol^{-1}$
$(f)$ Common salt: $NaCl$
Molecular mass: $23 + 35.5 = 58.5 \, g \, mol^{-1}$

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Similar Questions

$(a)$ What are molecules? Using examples, differentiate between the molecules of an element and a compound.
$(b)$ Derive the chemical formulae of the molecules formed between the following ions:
$(i)$ $Al^{3+}$ and $SO_{4}^{2-}$
$(ii)$ $Ba^{2+}$ and $NO_{3}^{-}$

$(a)$ Define polyatomic ions. Write an example.
$(b)$ Calculate the formula unit mass of $CaCO_{3}$. (Atomic mass of $C = 12 \ u, Ca = 40 \ u, O = 16 \ u$)
$(c)$ Calculate the molecular mass of the following:
$(i)$ $HNO_{3}$
$(ii)$ $CH_{3}COOH$
(Atomic mass of $H = 1 \ u, N = 14 \ u, O = 16 \ u, C = 12 \ u$)

Verify by calculating that:
$(a)$ $5$ moles of $CO_2$ has a higher mass than $5$ moles of $H_2O$.
$(b)$ $120 \, g$ of calcium and $120 \, g$ of magnesium elements have a mole ratio of $3:5$.

$A$ $0.24 \, g$ sample of a 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.

Give three differences between an atom and a molecule.

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