NEET Chemistry Some Basic Concepts in Chemistry MCQs

A mixture of $CaCO_3$ and $MgCO_3$ weighing 1.84 g on heating leaves a residue weighing 0.96 g. If the percentage by mass of $CaCO_3$ in the original mixture is x%, what is the value of x/2?

A mixture of $CO$ and $CO_2$ weighing 1.12 g is treated with an excess of red hot $CuO$. The $CO$ is converted to $CO_2$. The total weight of $CO_2$ produced is 1.6 g. What was the weight percentage of $CO$ in the original mixture?

Two elements X and Y combine to form two compounds $XY_2$ and $X_2Y_3$. If 0.05 moles of $XY_2$ weighs 5 g and 0.10 moles of $X_2Y_3$ weighs 20 g, find the atomic masses of X and Y.

A hydrocarbon contains 82.76% carbon by mass. If 0.90 g of the hydrocarbon occupies a volume of 390 $cm^3$ at STP, what is its molecular formula?

Two organic compounds X and Y have the same empirical formula $CH_2O$. Compound X has a molar mass of 30 g/mol while compound Y has a molar mass of 90 g/mol. If 0.3 moles of X contains the same number of oxygen atoms as 'm' grams of Y, what is the value of 'm'?

A gaseous organic compound has an empirical formula $C_xH_y$. When 0.150 g of the compound is completely combusted, it produces 0.225 g of $CO_2$ and 0.090 g of $H_2O$. Given the vapor density of the compound is 29, what is the molecular formula?

Two elements, X and Y, combine to form two compounds. Compound A contains 27.3% X and 72.7% Y by mass. Compound B contains 42.9% X and 57.1% Y by mass. If the mass of Y is fixed at 100g in both compounds, which of the following represents the masses of X in the two compounds, consistent with the Law of Multiple Proportions?

A mixture of $KClO_3$ and $KCl$ weighing 4.96 g was heated to produce $O_2$. The evolved oxygen occupied 448 mL at STP. What percent of the original mixture was $KClO_3$?

10 g of a mixture of $NaHCO_3$ and $Na_2CO_3$ has 1.68 g of $NaHCO_3$. On heating, if the residue weighs 8.28 g, what is the percentage purity of $Na_2CO_3$ in the mixture?

A 1.00 g sample containing $BaCl_2\cdot2H_2O$ is heated to a constant mass of 0.835 g. What was the mass percent of barium in the original sample?