Question

1. What is meant by standard temperature and pressure ?
2. Name a gas that is formed by the action of ultraviolet rays of the sun on oxygen.
3. Name the substance which causes permanent hardness in water.
4. Name a salt, the solubilty of which increases rapidly with rise of temperature.
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Answer 1

Definition. Standard Temperature and Pressure (STP) is defined as 0 degrees Celsius and 1 atmosphere of pressure.

Answer 2

Explanation:

1 Definition. Standard Temperature and Pressure (STP) is defined as 0 degrees Celsius and 1 atmosphere of pressure. Do not confuse STP with the STP Products Company, a maker of oil and fuel additives... unless you are reading one of their Safety Data Sheets!

2 ozone

In the stratosphere, ozone is created primarily by ultraviolet radiation. When high-energy ultraviolet rays strike ordinary oxygen molecules (O2), they split the molecule into two single oxygen atoms, known as atomic oxygen. A freed oxygen atom then combines with another oxygen molecule to form a molecule of ozone

3 Permanent hardness (mineral content) is generally difficult to remove by boiling. If this occurs, it is usually caused by the presence of calcium sulfate/calcium chloride and/or magnesium sulfate/magnesium chloride in the water, which do not precipitate out as the temperature increases.

4 Answer: Sodium nitrate , Potassium nitrate , Potassium bromide show increase in their solubility with rise in temperature.