Answer:
The answer is 1.06g.
Explanation:
Analysis of question:
1. Identify the information in the question given.
- volume of HCl is 2 dm3
- pH of HCl is 2.0
2. What the question want?
- mass of Na2CO3 is ?(unknown)
- 3. Do calculation.
- 1st-Write a balanced chemical equation:
Na2CO3 + 2HCl (arrow) 2NaCl + H20 + CO2
- 2nd-Determine the molarity of HCl with the value of 2.0.
pH= -log[H+]
2.0= -log[H+]
log[H+]= -2.0
[H+]= 10 to the power of negative 2(10-2)
=0.01 mol dm-3
molarity of HCl is 0.01 mol dm-3
- 3rd-Find the number of moles of HCl
n=MV
=0.01 mol dm-3 × 2 dm3
=0.02 mol of HCl
- 4th-Find the second mol of it.
Based on the chemical equation,
2.0 mol of HCl reacts with 1.0 mol of Na2CO3
0.02 mol of HCl reacts with 0.01 mol of Na2CO3
<u>N</u><u>a</u>2CO3>a=<u>1</u><u> </u>mol
<u>2</u><u>H</u>Cl>b=<u>2</u><u> </u>mol
mass= number of mole × molar mass
g=0.01 × [2(23)+ 12+ 3(16)]
g=0.01 × 106
# =1.06 g.
The molar enthalpy of combustion in kj/mol of magnesium is 620 kj/mol, Option D is the correct answer.
<h3>What is enthalpy of Combustion ?</h3>
The energy released when a fuel is oxidized by an oxidizing agent is called enthalpy of Combustion.
It is given that
a 1.0 g sample of magnesium is burned to form MgO. in doing so, 25.5 kj of energy are released.
Molecular weight of Magnesium = 24.35g
24.35 g makes 1 mole of Mg
1g = 1/24.35
For 0.04 moles 25.5 kJ is released
for 1 mole 25.5 *1/.04
= 620 kj/mol
Therefore the molar enthalpy of combustion in kj/mol of magnesium is 620 kj/mol.
To know more about enthalpy of combustion
brainly.com/question/14754029
#SPJ1
They all have a certain amount of protons electrons and neutrons.
Answer: it consists of two simple machines: a lever and a wheel and axle. Effort is applied to the lever by picking up the handles of the wheelbarrow.
Explanation:
