III. State TRUE or FALSE
Most humus is present in O-horizon of soil. __________
Water cannot penetrate through the bedrock. __________
Particles of loamy soil are larger than clayey soil. __________
Sandy soil is gritty and loose. __________
Loamy soil is the best soil for gardening.
Alternate cooling and heating can weather rocks. _____
Soils that are sandy are very useful for growing crops. _____
Groundwater is found in bedrock. _____
The roots of plants bind soil particles together and prevent its erosion. _____
Plastic decays very quickly. _____
Crop rotation replenishes soil.
Answers
Answer: A short introduction: When metals react with other substances like water, oxygen or acids, the metal atoms form positive ions (characteristic chemical behaviour of metals.
The chemical reactivity of a metal (e.g. how fast it reacts) is related to its tendency to form positive ions (cations). From quite simple experiments, metals can be arranged in order of their reactivity in what we call a reactivity series.
In order of decreasing reactivity, the metals potassium, sodium, lithium, calcium, magnesium, zinc, iron and copper can be put in order of their reactivity from their reactions with water and dilute acids.
The non-metals hydrogen and carbon are often included in the reactivity series, and this quite important when considering the method by which a metal can be extracted from its ore.
You should also note that a more reactive metal will displace a less reactive metal from one of its compounds.
Explanation: