The ratio of the molar amounts of $H_2S$ needed to precipitate the metal ions from $20 \ mL$ each of $1 \ M \ Cd(NO_3)_2$ and $0.5 \ M \ CuSO_4$ is

What ratio by mass of $Ne$ and $CH_4$ should be mixed so that the partial pressure exerted by each gas is the same?

In the combustion of $2.0 \ g$ of methane,$25 \ kcal$ of heat is liberated. The heat of combustion of methane would be ..... $kcal$.

$A$ cylinder of cooking gas in a household contains $11.6 \, kg$ of butane. The thermochemical reaction for the combustion of butane is,
$2 C_4H_{10(g)} + 13 O_{2(g)} \longrightarrow 8 CO_{2(g)} + 10 H_2O_{(l)}$
$\Delta H = -2658 \, kJ/mol$
If the household needs $15000 \, kJ$ of energy per day,the cooking gas cylinder will last for about $...... \, days$.

At $STP$,the decomposition of $1 \, g$ of $CaCO_3$ will produce ........... liters of $CO_2$.

What is the value of $w$ (mass of solute in grams) required to prepare a definite volume of a standard solution of known normality $(N)$?
[$N = \text{normality}$,$E = \text{equivalent weight}$,$V = \text{volume of solution in } mL$]