IGCSE Chemistry: Specimen Questions with Answers 29 - 31 of 240

Presence of Hydroxide ions in a solution suggests the presence of ________ in the solution.

Answer

Explanation

Presence of Hydroxide ions in a solution suggests the presence of base in the solution. ions indicate the presence of base.

The diagram shows an experiment.

Choices

Choice (4)
a.
b.
c.
d.

Answer

Explanation

Correct option is C because when we react with it gives as shown in figure. is basic while is neutral so whole solution is basic. Under basic solution Blue litmus is no color change and red litmus is changes its color to blue.

Aluminum and gallium are in Group III of the Periodic Table.

1. The heat from your hand is sufficient to melt gallium.

   Describe the change in state from solid to liquid in terms of the kinetic particle theory. In your answer include

   • the difference in arrangement and closeness of the particles in a solid and a liquid,
   • the difference in the motion of the particles in a solid and a liquid.

Explanation

Elemental gallium is a soft, silvery blue metal at standard temperature and pressure, a brittle solid at low temperatures, and a liquid at temperatures greater than (above room temperature, but below the normal human body temperature) . The melting point of gallium is used as a temperature reference point. So the gallium become liquid when comes in contact of human body. The kinetic human theory is given by diagram.