Answer:
its a trick yo have to add it all
Explanation:
Answer:
9.1 KJ
Explanation:
First we must find the number of moles of HBr involved;
number of moles of HBr= mass of HBr/ molar mass of HBr
But molar mass of HBr= 80.91 g/mol
Given mass of HBr from the question= 20.1g
Hence;
Number of moles of HBr= 20.1 g/80.91g
Number of moles of HBr= 0.25 moles of HBr
If 2 moles of HBr has a heat of formation of 72.80KJ
Then 0.25 moles of HBr will have a heat of formation of 0.25× 72.80/2= 9.1 KJ
Therefore; 20.1 g of HBr will have a heat of formation of 9.1 KJ
Answer: chemical weathering
2 moles of NaOH dissolved in 1 litre of solution is the solution with more concentration.
Answer: Option A
<u>Explanation:</u>
Concentration of solution is the measure of the amount of solute dissolved in the solvent of the solution. So this is measured using the molarity of the solution. Molarity is determined as the number of moles of the solute present in the given amount of solvent.

In this present case, the option A gives the molarity of 2 M as

But the second option, mass of NaOH is given. So we have to determine the molarity. First we have to find the molar mass of NaOH. We know that 1 mole of NaOH will contain 40 g/mole.
1 g of NaOH = 40 g of NaOH
1 g of NaOH = 1/40 moles
So 2 g of NaOH will contain
which is equal to 0.05 moles of NaOH.
Thus, the molarity of 2 g of NaOH will be
Molarity =
=0.05 M
Thus, the option A is having higher concentration as the molarity is more for 2 moles of NaOH dissolved in 1 l of solution.