Answer:
Neodymium makes flints inside of lighters. It also takes away the green color off of glass. Rhenium is added with tungsten and molybdenum which makes filaments for lamps. Sulfur makes sulfuric acid which makes batteries and cleaners and can process ores.
Explanation:
An interesting fact for each element:
Neodymium is known for the atomic symbol Nd and the atomic number 60.
Rhenium is known for the atomic symbol Re and the atomic number 75.
Sulfur is known for the atomic symbol S and the atomic number 16.
I hope the Answer answers your question. I gave you some facts to remember those elements in the periodic table!
Answer : The reaction is endothermic.
Explanation :
Formula used :

where,
= change in temperature = 
Q = heat involved in the dissolution of KCl = ?
m = mass = 0.500 + 50.0 = 50.5 g
c = specific heat of resulting solution = 
Now put all the given value in the above formula, we get:


The heat involved in the dissolution of KCl is positive that means as the change in temperature decreases then the reaction is endothermic and as the change in temperature increases then the reaction is exothermic.
Hence, the reaction is endothermic.
Answer: Option (b) is the correct answer.
Explanation:
Vitamins which are soluble in water are known as water-soluble vitamins. And, vitamins which remain insoluble in water are known as water-insoluble vitamins.
Water-soluble vitamins are able to be easily excreted by the human body through urine. For example, vitamin C and vitamin B-complex are water soluble vitamins.
Thus, we can conclude that water-soluble vitamins are easily excreted in the urine.
To find the Percent Composition of an atom, you use this formula:
Mass of element in the compound you're studying on ( in this case it's 5 since there is 5 Hydrogens) over the mass of the compound (which is here 79), Multiplied by 100 since you want a percent.
So we get:

So you get about:


So, the percent composition of Hydrogen in NH4HCO3 is 6.3%
Hope this Helps! :D