Classify the following as chemical
or physical changes:
• cutting of trees,
• melting of butter in a pan,
• rusting of almirah,
• boiling of water to form steam,
• passing of electric current,
through water and the water
breaking down into hydrogen
and oxygen gases,
• dissolving common salt in
water,
• making a fruit salad with raw
fruits, and
• burning of paper and wood.
To make a saturated solution, 36 g of sodium chloride is dissolved in 100 g of water
at 293 K. Find its concentration at this temperature.
Differentiate between homogen eous and heterogeneous mixtures with examples.
List the points of differences
between homogeneous and
heterogeneous mixtures.
The following is the cumulative frequency distribution (of less than type) of 1000 persons each of age 20 years and above. Determine the mean age.
At a fete, cards bearing numbers 1 to 1000, one number on one card, are put in a box. Each player selects one card at random and that card is not replaced. If the selected card has a perfect square greater than 500, the player wins a prize. What is the probability that
(i) the first player wins a prize?(ii) the second player wins a prize, if the first has won?
+91 94284 01196
© Copyright 2025. Doubtora. All Rights Reserved
