Answer:
2510
Explanation:
Since there are 10 milimetres in 1 centimetre, 1 cm = 10mm
There are 10 times as many milimetres as centimetres.
251cm X 10 = mm
251cm = 2510mm
Answer: The ion that contribute to water hardness are:
--> a. Ca2+
--> b. (HCO)3^- and
--> c. Mg2+
While K+ DOES NOT contribute to water hardness.
Explanation:
WATER in chemistry is known as a universal solvent. This is so because it is polar in nature and dissolves most inorganic solutes and some polar organic solutes to form aqueous solutions. It is composed of elements such as hydrogen and oxygen in the combined ratio of 2:1.
Water is said to be HARD if it does not lather readily with soap. There are two types of water hardness:
--> Permanent hardness: This is mainly due to the presence of CALCIUM and MAGNESIUM ions in the form of soluble tetraoxosulphate(VI) and chlorides. These ions are removed by adding washing soda or caustic soda.
--> Temporary hardness: This is due to the presence of calcium HYDROGENTRIOXOCARBONATES. It can be removed by boiling and using slaked lime.
Therefore from the above given ions, Ca2+,(HCO)3^- and Mg2+ contributes to water hardness.
Answer : Right
Explanation : The direction of reaction tends to proceed on right side under standard conditions; If the change in standard free energy ΔG for a particular reaction is negative. Also if the elements in their most stable forms as they exist under standard conditions. Then ΔG determines the direction and extent of chemical change. But under standard conditions the direction of the reaction will be to right.
"A neutron turns into a proton and an electron
Nominal mass does not change
atomic number decreases by one" -redbeardthegiant
The answer is a ) electromagnetic waves
