<u>Answer:</u> The number of moles of strontium bicarbonate is 
<u>Explanation:</u>
Formula units are defined as lowest whole number ratio of ions in an ionic compound. It is calculate by multiplying the number of moles by Avogadro's number which is 
We are given:
Number of formula units of 
As,
number of formula units are contained in 1 mole of a substance.
So,
number of formula units will be contained in =
of strontium bicarbonate.
Hence, the number of moles of strontium bicarbonate is 
Answer:
d) cut the large sized Cu solid into smaller sized pieces
Explanation:
The aim of the question is to select the right condition for that would increases the rate of the reaction.
a) use a large sized piece of the solid Cu
This option is wrong. Reducing the surface area decreases the reaction rate.
b) lower the initial temperature below 25 °C for the liquid reactant, HNO3
Hugher temperatures leads to faster reactions hence this option is wrong.
c) use a 0.5 M HNO3 instead of 2.0 M HNO3
Higher concentration leads to increased rate of reaction. Hence this option is wrong.
d) cut the large sized Cu solid into smaller sized pieces
This leads to an increased surface area of the reactants, which leads to an increased rate of the reaction. This is the correct option.
Answer : The mass of
is, 295.323 grams
Solution :
First we have to calculate the moles of
.

Now we have to calculate the moles of NaBr.
The balanced chemical reaction is,

From the balanced reaction we conclude that
As, 2 moles of
react with 2 moles of 
So, 2.87 moles of
react with 2.87 moles of 
Now we have to calculate the mass of NaBr.


Therefore, the mass mass of
is, 295.323 grams
I think the answer is -12.7