2021 - JAMB Chemistry Past Questions and Answers - page 3
220g of carbon dioxide contains ----- moles
5
6
3
4
One mole of carbon dioxide molecules has a mass 44.01g.
220/44.01 = 4.9989
Hence, 5 mole of carbon dioxide molecules.
The inherited traits of an organism are controlled by?
RNA molecules
Nucleotides
DNA molecules
Enzymes
DNA is the hereditary material in humans and almost all other organisms. DNA codes genetic information for the transmission of inherited traits.
The most abundant rare gas in the atmosphere is?
He
Ne
Ar
Xe
Nitrogen (N2) is the most abundant naturally occurring gas is Nitrogen (N2), making up about 78% of air.
Oxygen (O2), on the other hand, is the second most abundant gas making up about 21%.
The heat required to raise the temperature of the body by 1k is called?
Specific heat
Thermal capacity
Water equivalent
None of the above
Heat capacity, also known as thermal capacity, is a physical property of matter defined as the amount of heat needed to cause a unit change in temperature in a given mass of material. More.
The nucleus of a hydrogen atom consists of a?
1 proton only
1 proton, 2 neutron
1 neutron only
1 electron only
The hydrogen atom is the simplest of all atoms, consisting of a single proton and a single electron.
The metal used to recover copper from a solution of copper sulphate is?
Na
Ag
Hg
Fe
The ideal metals are metals that are stronger reducing agents than copper but not reactive enough to react with the water that the solution consists of.
Examples of such metals:
- Zinc
- Aluminium
- Iron
The nucleus of an atom consists of?
Electrons and neutrons
Electrons and protons
Protons and neutrons
None of the above
The nucleus of an atom consists of protons and neutrons.
The electron is a negatively charged subatomic particle that orbits the nucleus of an atom.
A solution contains 20g of solute in 180g of solvent. If the solvent is water, what is the concentration of the solution in terms of mass by mass percentage?
11.%
22.2%
10%
20%
Mass of solution = Mass of solute + Mass of solvent → 20g + 180g
Hence, Mass of solution = 200g
Mass Percent = \(\frac{Mass of Solute}{Mass of Solution} * 100%\)
Mass percent = \(\frac{20}{200} * 100%\)
Mass percent = 10%
The only metal that is anti-bacterial is?
Iron
Sodium
Aluminium
Copper
An element having the atomic number 17 will resemble which of the following elements having an atomic number as given below?
33
35
18
19
The Group 7 elements are called "halogens". They appear in the vertical column, second from the right, in the periodic table.
Bromine(35) is among the elements in the Group.