How would you confirm that a colorless liquid given to you is pure water?

Why is blood a mixture and graphite an element? Mention any one reason for each.

Classify the following as chemical or physical changes:
$1$. Cutting of trees
$2$. Melting of butter in a pan
$3$. Rusting of almirah
$4$. Boiling of water to form steam
$5$. Passing of electric current through water and the water breaking down into hydrogen and oxygen gases
$6$. Dissolving common salt in water
$7$. Making a fruit salad with raw fruits
$8$. Burning of paper and wood

Which of the following is an element?

How is heating of sugar and heating of ammonium chloride different from each other? Explain your answer.

Elements are classified as metals,non-metals,and metalloids. Give any one property of each. Also,give one example of each.