Which of the following activities best demonstrates that there is a force of attraction between particles of matter?
- A.Compressing a sponge
- B.Dissolving sugar in water
- C.Breaking a chalk stick
- D.Heating ice to form water
Correct answer
Explanation
The correct answer is C, Breaking a chalk stick. Force has to be applied to break the chalk because its particles hold one another together, and that pull is the force of attraction between particles.
Every substance is made of particles that attract one another, and the strength of that attraction decides how hard a thing is to break. The attraction is strongest in solids, less in liquids and least in gases, which is why an iron rod needs a hammer, water can be separated with a finger and air offers no resistance at all. The school activity of breaking chalk, then a pencil and then an iron nail shows the difference in this force from one solid to another.
Option A is wrong because compressing a sponge only squeezes out the air in its pores. Option B is wrong because dissolving sugar shows diffusion and the spaces between particles. Option D is wrong because heating ice shows a change of state, not the attraction itself.
Exam tip: attraction between particles is strongest in solids, weaker in liquids and weakest in gases.
Practice Questions
View allThe fact that the planets move around the Sun, not in circles but in ellipses, was first demonstrated by
- A.Galileo
- B.Martin Luther
- C.Johannes Kepler
- D.Copernicus
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In 1609 Kepler showed that the planets move around the Sun in elliptical orbits, with the Sun at one focus of the ellipse.
Read the full explanation →Which one of the following statements is correct?
- A.Urea is produced in liver.
- B.Urea is produced in blood.
- C.Urea is produced from digestion of starch.
- D.Urea is produced in lung and kidney.
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Liver cells turn the toxic ammonia released from the breakdown of amino acids into urea through the ornithine cycle, also called the urea cycle.
Read the full explanation →Which one of the following is the correct sequence of passage of light in a compound microscope?
- A.Condenser-Objective lens-Eyepiece-Body tube
- B.Objective lens-Condenser-Body tube-Eyepiece
- C.Condenser-Objective lens-Body tube-Eyepiece
- D.Eyepiece-Objective lens-Body tube-Mirror
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Light passes through the condenser to the specimen, is picked up by the objective lens, travels up the body tube and reaches the eye through the eyepiece.
Read the full explanation →Which one of the following statements regarding haemoglobin is correct?
- A.Haemoglobin present in RBC can carry only oxygen but not carbon dioxide.
- B.Haemoglobin of RBC can carry both oxygen and carbon dioxide.
- C.Haemoglobin of RBC can carry only carbon dioxide.
- D.Haemoglobin is only used for blood clotting and not for carrying gases.
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It binds oxygen at its iron-containing haem groups and carries some carbon dioxide on its protein chains. Each haemoglobin molecule has four polypeptide chains and four haem groups, and each haem iron can hold one oxygen molecule, forming oxyhaemoglobin in the lungs.
Read the full explanation →Which one of the following statements regarding histone proteins is correct?
- A.Histones are proteins that are present in mitochondrial membrane.
- B.Histones are proteins that are present in nucleus in association with DNA.
- C.Histones are proteins associated with lipids in the cytosol.
- D.Histones are proteins associated with carbohydrates in the cytosol.
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They are the proteins around which DNA winds to form chromatin in the nucleus of eukaryotic cells. Histones are small basic proteins, rich in the positively charged amino acids lysine and arginine, which attract the negatively charged phosphate groups of DNA.
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