6a. physical reaction
6b. endothermic reaction
7a. physical reaction
7b. the reactants are carbon dioxide, water and light energy. the product is starch
7c. exothermic reaction
Answer:
The empirical formula is = 
Explanation:
Given that:- Mass of nickel = 2.241 g
Mass of the oxide formed = 2.852 g
Mass of the oxygen reacted = Mass of the oxide formed - Mass of nickel = 2.852 g - 2.241 g = 0.611 g
Molar mass of nickel = 58.6934 g/mol
Moles of nickel = 
= 0.03818 mol
Molar mass of oxygen = 15.999 g/mol
Moles of nickel = 
= 0.03818 mol
Taking the simplest ratio for Ni and O as:
0.03818 : 0.03818 = 1 : 1
<u>The empirical formula is =
</u>
Answer:
Chromosome is basically made of DNA and proteins.
Explanation:
Chromosomes contain thread like structure present inside the nucleus of the cell.Chromosome is generally made of DNA and proteins(Histone proteins).
The DNA is wrapped around the basic protein histone to provide support the chromosome structure.
The wrapping of DNA around the histone proteins helps in the formation of nucleosome which helps in the packing of DNA inside the chromosome.
C. the expansion of the universe is accelerating
