Which one of the following energy is stored in the links between the atoms ?
- A.Nuclear energy
- B.Chemical energy
- C.Potential energy
- D.Thermal energy
Correct answer
Explanation
The correct answer is B, Chemical energy. Chemical energy is the energy stored in the bonds that link atoms together in molecules.
When a chemical reaction breaks old bonds and forms new ones, this stored energy is released or absorbed. Burning coal, petrol or LPG, digesting food and using a battery all release chemical energy, which appears as heat, light or electrical energy. Food and fuels are therefore described as stores of chemical energy, and the energy content of food is measured in calories or joules.
A is wrong: nuclear energy is stored in the nucleus, in the forces that hold protons and neutrons together, not in the links between atoms.
C is wrong: potential energy, in the usual sense, is the energy a body has because of its position or shape, such as a raised stone or a stretched spring.
D is wrong: thermal energy is the energy of the random motion of particles, which we sense as heat.
Exam tip: bonds between atoms = chemical energy; inside the nucleus = nuclear energy.
Practice Questions
View allSyngamy results in formation of
- A.haploid zygote
- B.diploid zygote
- C.non-motile male gametes
- D.motile male gametes
Show answer
Syngamy is the fusion of a male and a female gamete, and since each gamete is haploid, their union gives a diploid zygote.
Read the full explanation →Human insulin molecule is composed of one α-chain having 21 amino acids and one β-chain having 30 amino acids. How many functional insulin genes occur in adult humans?
- A.One
- B.Two
- C.Three
- D.Four
Show answer
Humans have a single functional insulin gene, INS, on the short arm of chromosome 11, and both chains of insulin come from it.
Read the full explanation →Which one of the following is the value of one nanometer?
- A.10⁻⁷ cm
- B.10⁻⁶ cm
- C.10⁻⁴ cm
- D.10⁻³ cm
Show answer
One nanometre is 10⁻⁹ metre, and since one metre is 100 (10²) centimetres, it equals 10⁻⁷ centimetre. The prefix nano means one billionth.
Read the full explanation →Which of the following is the general formula for saturated hydrocarbons?
- A.CₙH₂ₙ₊₂
- B.CₙH₂ₙ₋₂
- C.CₙH₂ₙ₊₁
- D.CₙH₂ₙ₋₁
Show answer
Saturated open-chain hydrocarbons are the alkanes, and every alkane fits the formula CₙH₂ₙ₊₂. In a saturated hydrocarbon every carbon atom is joined to others only by single bonds, so each carbon holds the largest possible number of hydrogen atoms.
Read the full explanation →Which one of the following is not an epidemic disease?
- A.Cholera
- B.Malaria
- C.Smallpox
- D.Elephantiasis
Show answer
Elephantiasis, or lymphatic filariasis, is an endemic disease: it stays steadily present in certain regions and develops slowly over years, rather than breaking out suddenly in a large number of people.
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