Atmospheric pressure decreases as the height of a surface above ground level increases. This is because, as the altitude increases:
•the number of air molecules decreases
•the weight of the air decreases
•there is less air above a surface
This is why aircraft that fly at high altitudes must be pressurised. If the air pressure is too low, humans cannot take in oxygen quickly enough to meet their bodies’ needs.
Answer:
A pH less than 7 is an acid, with number 1 indicating stronger acids
Explanation:
The pH scale has a range of 1 to 14. The following has been concluded on the pH scale:
1. Between 1 and 6 indicates an acid solution.
2. 7 indicates a neutral solution
3. Between 8 and 14 indicates an alkaline or basic solution.
Now with these information, we can answer the above questions as follow:
A pH less than 7 is an acid, with number 1 indicating stronger acids
Answer : In the reaction of Ca +
--->Ca
, the coefficient of Ca and
will be the same which will be 1.
Explanation : As per the rules of writing a chemical equation and balancing it properly, the number of elements in reactants side should be equal to the number of elements generated in product side. Hence when we use 1 molecule of Ca and one molecule of
then it generates 1 molecule of Ca
.
Nonmetals has the greatest tendency to become negative ions.
Explanation:
The oxidation number of chlorine can be -1, 0, +1, +3, +4, +5, or +7, depending on the substance containing the chlorine. The most common oxidation numbers are -1 (as in HCl and NaCl ) and 0 (as in Cl2 ).
