Any change in which the composition of material does not change that is it retains its identity but changes its state or form is known as a physical change.
The properties of metal to draw them into wires is known as ductility. When a copper is drawn into wire the only change that occurs is change in its shape and size no change will take place into its composition that is the wires are still possessing the properties of copper metal. Thus, a physical change takes place when copper is drawn into wire.
Answer:
Explanation:
1. New substances such as carbondioxide and water is formed.
2. There is evolution of gas bubbles. Gases are released.
3. There is either the absorption of energy or release of energy in form of light and energy.
4. The reaction is irreversible i.e it cannot be reversed, it is permanent once the reaction take place.
5. There is a change in both odor and smell.
A chemical change is a change where new substances are formed due to changes in the properties.
Answer:
This is an example of convection
Answer:
32km/hr
Explanation:
The question asks to calculate the average speed for a boat.
Mathematically, the average speed is the total distance divided by the total time
Let’s get the total distance traveled:
That would be 70km + 26km = 96km
Now the total time taken would be 3 as the boat did not move at all for an hour.
The average speed is thus 96/3 = 32km/hr
