Answer: True
Explanation: They are formed by the cooling and hardening of molten magma
Answer: 37.5grams of Cu(NO3)2
Cu(1mol) + 2HNO3(2mol) —> Cu(NO3)2 + H2
<em>125 grams of Cu(1mol) reacts with 75 grams of HNO3(2mol)</em>
<em><u>HNO3 is the limiting substance, therefore, 75 grams is the limiting quantity.</u></em>
<em>Therefore, 2mol of HNO3 forms 1mol of Cu(NO3)2</em>
<em>75 grams of HNO3 forms...75grams x 1mol/2mol = 37.5 grams of Cu(NO3)2</em>
ANSWER:
4 a) Specific elements have more than one oxidation state, demonstrating variable valency.
For example, the following transition metals demonstrate varied valence states: 
, 
, 
, etc.
Normal metals such as 
also show variable valencies. Certain non-metals are also found to show more than one valence state 
4 b) Isotopes are members of a family of an element that all have the same number of protons but different numbers of neutrons.
For example, Carbon-14 is a naturally occurring radioactive isotope of carbon, having six protons and eight neutrons in the nucleus. However, C-14 does not last forever and there will come a time when it loses its extra neutrons and becomes Carbon-12.
5 a) 
→ 
5 b) 
→ 
5 c) 
→ 
(already balanced so don't need to change)
5 d) 
→ 
5 e) 
→ 
EXPLANATION (IF NEEDED):
1. Write out how many atoms of each element is on the left (reactant side) and right (product side) of the arrow.
2. Start multiplying each side accordingly to try to get atoms of the elements on both sides equal.
EXAMPLE OF BALANCING:
The correct option is (a) H₂S : SO₂ = 2 : 2 and O₂ : H₂O = 3 : 2
<h3>What is molar Ratio ?</h3>
Molar ratio also known as stoichiometry is the ratio in which the reactants and products are either formed or reacted in the given equation
the balanced equation is as follows ;
2H₂S + 3O₂ --> 2SO₂ + 2H₂O
molar ratio can be determined by the coefficients of the compounds in the balanced reaction.
coefficient is the number in front of the chemical compound
coefficients for the compounds in this reaction are as follows ;
- H₂S - 2
- O₂ - 3
- SO₂ - 2
- H₂O - 2
therefore, correct option is (a) H₂S:SO₂ = 2:2 and O₂:H₂O = 3:2
Learn more about molar ratio here ;
brainly.com/question/17920577
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C, The atomic mass. This could also cause certain elements (i.e. Uranium, Plutonium) to radioactively decay in process called nuclear fission.
