General Science Mixed Quiz: Set 59

Bromine is a dark reddish-brown, dense, fuming liquid at ordinary room temperature, with a melting point of about minus 7 degrees Celsius and a boiling point of about 59 degrees Celsius.

Hooke's law holds only as far as the limit of proportionality, and that limit is either equal to or lower than the elastic limit, so statements 1 and 4 are the correct pair.

When two miscible liquids boil at temperatures far apart, ordinary distillation is enough, because the more volatile liquid boils off almost completely before the other begins.

Pisciculture is the rearing of fish in ponds, tanks and other managed waters, the Latin word piscis meaning fish.

This is the heat one gram of ice at 0 degrees Celsius must absorb to become one gram of water at 0 degrees Celsius; the temperature does not rise at all while it melts, because the energy goes into breaking the hydrogen-bonded lattice.

Galileo was the first to argue that, with air resistance removed, every body falls with the same acceleration regardless of its mass.

Brass is made by melting copper with zinc, and the resulting homogeneous mixture is harder than copper, easier to cast and machine and gives the familiar yellow colour used for utensils, fittings and musical instruments.

In electroplating the article to be coated is made the cathode, the plating metal serves as the anode, and both are dipped in an electrolyte containing a salt of that metal.

Evaporation is a surface phenomenon in which the fastest-moving molecules of a liquid break free. Doing so needs the latent heat of vaporisation, and that energy is drawn from the liquid left behind and from whatever the liquid touches, so both grow cooler.

Ashwagandha, whose botanical name is Withania somnifera, is called winter cherry in English because of the small red berry it bears inside a papery cover; it is also called Indian ginseng.

Ammonium chloride passes directly from the solid to the vapour state on heating, without melting, while common salt does not.

Litmus is a purple dye taken from lichens, and in the classification used in school science lichens are placed in Thallophyta, the group of simple plants whose body is an undifferentiated thallus with no true root, stem or leaf.

In a liquid the resistance to flow comes mainly from the attraction between neighbouring molecules. Heating gives the molecules energy to slip past one another, so the attraction matters less and the liquid thins; hot honey and warm engine oil pour far more easily than cold.

Ultraviolet light is a transverse wave, not a longitudinal one, so this statement is the wrong one. In an electromagnetic wave the electric and magnetic fields vibrate at right angles to each other and to the direction the wave travels, which is the definition of a transverse wave.

Chromatography separates substances that are dissolved in the same solvent and present in very small quantities, by letting the solution creep along a strip of filter paper.

The petiole is the stalk that joins a leaf blade to the stem; it belongs to the leaf, not to the flower, and a leaf without one is called sessile.

At ordinary atmospheric pressure carbon dioxide has no liquid stage: the solid passes straight into vapour at about minus 78.5 degrees Celsius.

When salt dissolves in water it breaks up into separate ions, which are far smaller than the wavelength of visible light, so they cannot scatter a beam sideways and the path of light through the liquid stays invisible.

Thomas Graham found in 1833 that a light gas spreads through a porous partition faster than a heavy one, and that the rates of two gases are in the inverse ratio of the square roots of their densities, and therefore of their molar masses.

In crystallisation a hot saturated solution is allowed to cool slowly, and as it cools only the required substance comes out of solution in the regular form of crystals while the impurities, present in smaller amounts, stay dissolved in the liquid that is left behind, which is called the mother…