A substance undergoes a change. Which of the following indicates that the change was a chemical change?
2 answers:
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Answer:
The combustion of 59.7 grams of methane releases 3320.81 kilojoules of energy
Explanation:
Given;
CH₄ + 2O₂ → CO₂ + 2H₂O, ΔH = -890 kJ/mol
From the combustion reaction above, it can be observed that;
1 mole of methane (CH₄) released 890 kilojoules of energy.
Now, we convert 59.7 grams of methane to moles
CH₄ = 12 + (1x4) = 16 g/mol
59.7 g of CH₄
1 mole of methane (CH₄) released 890 kilojoules of energy
3.73125 moles of methane (CH₄) will release ?
= 3.73125 moles x -890 kJ/mol
= -3320.81 kJ
Therefore, the combustion of 59.7 grams of methane releases 3320.81 kilojoules of energy
Answer:
2.01 M
Explanation:
Step 1: Calculate the moles of acetic acid (HC₂H₃O₂)
The molar mass of acetic acid is 60.05 g/mol. We will use this data to calculate the moles corresponding to 36.2 g of acetic acid.
Step 2: Convert the volume of solution to liters
We will use the relation 1000 mL = 1 L. We assume that the volume of solution is that of water (300 mL)
Step 3: Calculate the molarity of the solution
The molarity is equal to the moles of solute (acetic acid) divided by the liters of solution