Some Basic Concepts In Chemistry Questions

16 Practice QuestionsStart Practicing Now

[Easy]How many moles of oxygen atoms are present in 5.0 g of CaCO3? (Atomic masses: Ca=40, C=12, O=16)...
[Medium]The density of a gas at STP is 1.25 g L⁻¹. Its molar mass is approximately:...
[Easy]The mass percent of nitrogen in NH4 NO3 (Atomic masses: N=14, H=1, O=16) is:...
[Medium]When 9.0 g of aluminium reacts completely with oxygen, how many grams of Al2O3 are formed? (2Al + 3/2 O2 → Al2O3, M(Al)=27, M(Al2O3)=102)...
[Easy]0.50 mol of CaCO3 is heated strongly. How many liters of CO2 (at STP) are evolved? (CaCO3 → CaO + CO2)...
[Easy]Which statement correctly defines molality?...
[Easy]If 4.4 g of CO2 contains x molecules, what is x? (Molar mass CO2=44 g mol⁻¹)...
[Easy]A sample of methane contains 0.25 mol. How many hydrogen atoms are present?...
[Medium]A sample contains 3.011×10⁺23 atoms of an element. Its mass is 12 g. The element is:...
[Medium]Determine empirical formula of a compound with 52.17% C, 34.78% O and 13.04% H (Atomic masses: C=12, O=16, H=1)....
[Easy]Which statement is correct regarding Avogadro's hypothesis?...
[Easy]A hydrocarbon sample contains 75% carbon by mass and remainder hydrogen. Its empirical formula is (Atomic masses: C=12, H=1)...
[Medium]The limiting reagent in the reaction 2Al + 3Cl2 → 2AlCl3 when 10.0 g Al (M=27) reacts with 20.0 g Cl2 (M=71) is:...
[Easy]At STP, the volume occupied by 2.00 g of H2 gas (M=2) is approximately:...
[Easy]How many molecules of water are present in 0.25 mol of H2O?...
[Hard]Which pair of solutions contains the same number of moles of solute?...