The mass of the reaction system is conserved because, the mass lost from the reaction by the evolution of gas is collected inside a balloon to inflate it. Thus , the balloon and the flask creates a closed system where no mass is lost outside.
According to the law of conservation of mass, the mass can neither be created nor be destroyed. Thus the total mass of the system is conserved. However similar to the energy, mass can be transformed into energy.
As per this law, the total mass in a chemical reaction is conserved. Where, the total mass in the reactant side is equal to the total mass in the product side.
When the reaction flask is closed with a balloon, the gas if any evolved from the reaction will be collected to the balloon and it inflates. Thus the mass lost from the reaction system does not goes to the surroundings due to the closed system.
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B. Physical changes always involve the formation of a gas while chemical changes may not.
C. Physical changes can occur inside or outside the substance; chemical changes always occur outside.
D. Physical changes involve a change of state; chemical changes involve a change of shape.
Answer:
A is the answer.
Explanation:
Physical changes do not change the substance's composition but just the outside qualities. However, chemical changes change the composition of the substance and it's chemical properties.
Answer:
A
Explanation:
The correct answer is
C. Negative ions are attracted to the anode.
Answer:
50 g NaOH
General Formulas and Concepts:
Chemistry - Solutions
Explanation:
Step 1: Define
0.500 L
2.50 M NaOH
x moles of solute
Step 2: Define conversions
Molar Mass of Na - 22.99 g/mol
Molar Mass of O - 16.00 g/mol
Molar Mass of H - 1.01 g/mol
Molar Mass of NaOH - 22.99 + 16.00 + 1.01 = 40 g/mol
Step 3: Find moles of solute
2.50 M NaOH = x moles NaOH / 0.500 L
x = 1.25 moles NaOH
Step 4: Convert
= 50 g NaOH
Step 5: Check
We are given 3 sig figs. Since our final answer has 2 sigs, there is no need to round.