<h2>Let us solve for it </h2>
Explanation:
Magnesium oxide
- It is MgO
- Its molecular mass is : 24 +16=40 g
- When MgO decomposes it forms = 3.54 g of oxygen gas
- when 40 g of MgO decomposes it forms = 16g of oxygen
- or we can say that :
- 16g of oxygen is produced when 40 g of MgO is decomposed .
- 1g of oxygen will be formed from =40/16g of MgO
- 3.54 g of oxygen will be formed = 40/16 x 3.54 =8.85g of MgO
Answer : 5.405 moles of
are equivalent to 97.3 grams of 
Solution : Given,
Mass of
= 97.3 g
Molar mass of
= 18 g/mole
Formula used :

or,

Now put all the given values in this formula, we get the moles of 

Therefore, 5.405 moles of
are equivalent to 97.3 grams of 
This problem is requiring the balanced chemical equation that takes place when copper hydroxide and potassium sulfate are produced when reacting potassium hydroxide with copper sulfate.
<h3>Balancing chemical equations:</h3>
In chemistry, balancing chemical equations is based on the law of conservation of mass, which demands us to have equal number of atoms on both sides of the chemical equation. This can be accomplished by inserting coefficients in front of the chemical species.
For this particular case, we have potassium hydroxide with copper sulfate on the reactants side, however, copper can be copper (I) or copper (II) as it has 1+ and 2+ as its possible oxidation numbers. In addition, copper hydroxide and potassium sulfate as the products. Hence, we can assume this is all about copper (II) so we can write:

As we can see, potassium, hydrogen and oxygen have two atoms each on the products side, but just one on the reactants side; drawback we can overcome by putting a 2 in front of KOH so as to balance it:

Learn more about balancing chemical equations: brainly.com/question/8062886
<em>The formula of calcium carbonate is CaCO3
</em>
<em>The formula of nitric acid is HNO3.
</em>
<em>When put together:</em>
<em>CaCO3 + HNO3 </em><em>= </em><em>Ca(NO3)2 + CO2 + H2O
</em>
<em>
The balanced equation:</em>
<em>
CaCO3 + 2HNO3</em><em> = </em><em>Ca(NO3)2 + CO2 + H2O
</em>
<em>
</em>
<em></em>
Answer:
B)3
Explanation:
I'm assuming the 2 is meant to be smaller. If it were a regular size 2 the answer would be 2 and that isn't an option