Which of these involves the formation of a new chemical substance?
1 answer:
Which of these involves the formation of a new chemical substance?
a. evaporation of gasoline
b. mixing salt and pepper
c. dissolving sugar in tea
d. rusting of an iron chain
- D. Rusting of an iron chain
<u>A. Evaporation of gasoline</u>
- It does not form any chemical substance. Evaporation, is part of a physical change. Physical change only changes in its physical characteristics. Evaporation changes from liquid, to gas. Therefore, it is a physical change.
<u>B. Mixing salt and pepper</u>
- No new substance formed. It does not form any chemical substance nor chemical change. When you mix salt and pepper, it only is a mixture wherein no new material can be form. Therefore, this is physical change as well.
<u>C. Dissolving sugar in tea</u>
- When you dissolve sugar in your tea, it only changes the taste of the tea to sweet. Taste is part of the characteristic of physical change. It does not form any chemical substance nor chemical change. Therefore, this is physical change.
<u>D. Rusting of an iron chain</u>
- Rusting is one of the common examples of chemical change in our daily lives. Rust is the new substance formed. However, this is considered as chemical change because this is irreversible or cannot be returned to its original substance/material. Finally, rusting of an iron chain involves the formation of new chemical substance.
<em><u>Hence, the answer is D. Rusting of an iron chain.</u></em>
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The question is incomplete, here is the complete question:
Methane gas and chlorine gas react to form hydrogen chloride gas and carbon tetrachloride gas. What volume of hydrogen chloride would be produced by this reaction if 1.1 mL of methane were consumed? Be sure your answer has the correct number of significant digits.
<u>Answer:</u> The volume of hydrogen chloride produced in the reaction will be 4.4 mL
<u>Explanation:</u>
We are given:
Volume of methane gas = 1.1 mL
The chemical equation for the reaction of methane gas and chlorine gas follows:
Moles of methane gas = 1 mole
Moles of hydrogen chloride gas = 4 moles
The relationship of number of moles and volume at constant temperature and pressure was given by Avogadro's law. This law states that volume is directly proportional to number of moles at constant temperature and pressure.
The equation used to calculate number of moles is given by:
where,
are the volume and number of moles of methane gas
are the volume and number of moles of hydrogen chloride
We are given:
Putting values in above equation, we get:
Hence, the volume of hydrogen chloride produced in the reaction will be 4.4 mL