A student wrote a chemical equation as shown. Fe2O3 + 3H2 → Fe + H2O
What should the student do to balance the equation?

A. Add a coefficient 2 before Fe and a 3 before H2O
B. Add a coefficient 3 before Fe and a 2 before H2O
C. Add a coefficient 4 before Fe and a 5 before H2O
D. Add a coefficient 5 before Fe and a 4 before H2O

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

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we need the questions , i may then you.

what is the average time it took the car to travel 0.25 meters?

⇒ 2.23 seconds

what is the average time it took the car to travel 0.50 meters?

⇒ 3.13 seconds