A neutral atom of magnesium-24 has atomic number 12. How many protons, neutrons, and electrons does it contain?
Atomic Structure And Bonding
Question · Easy
Which statement best describes an ionic bond?
Which subatomic particle has a relative charge of zero?
Sodium has atomic number 11. What is the ground-state electron arrangement of a sodium atom?
A covalent bond is best described as:
Which ion has the largest ionic radius?
Question · Medium
According to VSEPR theory, what is the molecular shape of ammonia, NH3?
Why is a sodium ion, Na+, smaller than a sodium atom?
Metals such as aluminium can be hammered into thin sheets. Which bonding feature best explains this malleability?
Which of the following molecules is polar?
Across Period 3 from sodium to chlorine, the first ionization energy generally:
Aluminium has atomic number 13. What is the electron arrangement of the Al3+ ion?
Boron trifluoride, BF3, contains polar B−F bonds but the molecule is non-polar. Why?
Question · Hard
Which substance is expected to have the highest melting point?
F− and Na+ are isoelectronic. Why is the ionic radius of F− larger than that of Na+?
How many moles of water are present in 36 g of H2O? Use Ar(H) = 1 and Ar(O) = 16.
Quantitative Chemistry
What is the molar mass of sodium carbonate, Na2CO3? Use Ar(Na) = 23, Ar(C) = 12 and Ar(O) = 16.
How many molecules are present in 0.250 mol of carbon dioxide? Use NA = 6.02 × 10^23 mol−1.
A solution contains 0.50 mol of NaOH in 250 mL of solution. What is its concentration in mol/L?
Methane burns according to CH4(g) + 2O2(g) → CO2(g) + 2H2O(g). How many moles of CO2 are produced from 8.0 g of CH4? Use Ar(C) = 12 and Ar(H) = 1.
What amount of NaOH is present in 250 mL of 0.40 mol/L NaOH solution?
A hydrocarbon is 85.7% carbon and 14.3% hydrogen by mass. What is its empirical formula? Use Ar(C) = 12 and Ar(H) = 1.
What is the percentage by mass of oxygen in Fe2O3? Use Ar(Fe) = 56 and Ar(O) = 16.
20.0 mL of 0.100 mol/L HCl is neutralized by 25.0 mL of NaOH. The equation is HCl + NaOH → NaCl + H2O. What is the concentration of the NaOH?
A sample of hydrogen gas occupies 11.2 L at STP. How many moles of H2 are present? Take the molar volume of a gas at STP as 22.4 L/mol.
10.0 mL of 2.00 mol/L hydrochloric acid is diluted with water to a final volume of 250 mL. What is the concentration of the diluted solution?
A student obtains 9.60 g of copper from a reaction whose theoretical yield is 12.0 g. What is the percentage yield?
2.76 g of K2CO3 is dissolved and made up to 250 mL of solution. What is the concentration of K2CO3? Use Ar(K) = 39, Ar(C) = 12 and Ar(O) = 16.
4.8 g of magnesium is burned in 4.0 g of oxygen: 2Mg(s) + O2(g) → 2MgO(s). What mass of MgO can form? Use Ar(Mg) = 24 and Ar(O) = 16.
5.00 g of hydrated copper(II) sulfate, CuSO4·xH2O, is heated to constant mass. 3.20 g of anhydrous CuSO4 remains. What is x? Use Ar(Cu) = 63.5, Ar(S) = 32, Ar(O) = 16 and Ar(H) = 1.
A compound contains 2.00 g of carbon and 0.336 g of hydrogen. Its relative molecular mass is 42. What is its molecular formula? Use Ar(C) = 12 and Ar(H) = 1.
25.0 mL of 0.200 mol/L H2SO4 is titrated with 0.100 mol/L NaOH. The equation is H2SO4 + 2NaOH → Na2SO4 + 2H2O. What volume of NaOH is required for complete neutralization?
What is the general formula of the unbranched alkane homologous series?
Organic Chemistry
Which functional group is present in ethanol, CH3CH2OH?
A hydrocarbon that contains only carbon–carbon single bonds is described as:
What is the IUPAC name of the straight-chain alkane CH3CH2CH3?
Which functional group characterizes carboxylic acids such as ethanoic acid?
Small identical molecules that join together to form a long-chain polymer are called:
How many structural isomers have the molecular formula C4H10?
Which hydrocarbon decolorizes bromine water in the dark by an addition reaction?
Ethanoic acid is warmed with ethanol and a few drops of concentrated sulfuric acid. What organic product is formed?
The products of the complete combustion of propane in excess oxygen are:
Members of a homologous series have the same functional group and:
Controlled oxidation of ethanol with acidified potassium dichromate can produce ethanoic acid. Ethanol is acting as which class of alcohol in this conversion?
Polyethene is formed from ethene by:
Tollens’ reagent (ammoniacal silver nitrate) gives a silver mirror with which compound?
Which molecular formula represents an unsaturated hydrocarbon?
In the petrochemical industry, long-chain alkanes are broken into shorter alkanes and alkenes. This process is called:
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