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Is Matter Around Us Pure

Question
CBSEENSC9005946
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A car of mass 1000 kg moving with a velocity of 45 km/h collides with a tree and comes to a stop in 5 s. What will be the force exerted by the car on the tree?

Solution

Here, 
Mass of car, m = 1000 kg
Initial velocity, u = 45 km/hr =  fraction numerator 45 cross times 1000 over denominator 3600 end fraction space equals space 25 over 2m/s
Final velocity = 0 m/s
Time taken for car to come to a halt = 5 s
Therefore, force is given by
F =  m open parentheses fraction numerator v minus u over denominator t end fraction close parentheses space equals space 1000 open parentheses fraction numerator 0 minus begin display style bevelled 25 over 2 end style over denominator 5 end fraction close parentheses space equals space minus 2500 space N
The negative sign shows the retarding nature of force. 

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Which separation techniques will you apply for the separation of the following?


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Write the steps you would use for making tea. Use the words—solution, solvent, solute, dissolve, soluble, insoluble, filtrate and residue.

Pragya tested the solubility of three different substances at different temperatures and collected the data as given below (results are given in the following table, as grams of substance dissolved in 100 grams of water to form a saturated solution).

Substance Dissolved

Temperature in K

283

293

313

333

353

Potassium nitrate

21

32

62

106

107

Sodium chloride

36

36

36

37

37

Potassium chloride

35

35

40

46

54

Ammonium chloride

24

37

41

55

66


What mass of potassium nitrate would be needed to produce a saturated solution of potassium nitrate in 50 grams of water at 313 K?

Pragya makes a saturated solution of potassium chloride in water at 353 K and leaves the solution to cool at room temperature. What would she observe as the solution cools? Explain.

Substance Dissolved

Temperature in K

283

293

313

333

353

Potassium nitrate

21

32

62

106

107

Sodium chloride

36

36

36

37

37

Potassium chloride

35

35

40

46

54

Ammonium chloride

24

37

41

55

66


Find the solubility of each salt at 293 K. Which salt has the highest solubility at this temperature?

Substance Dissolved

Temperature in K

283

293

313

333

353

Potassium nitrate

21

32

62

106

107

Sodium chloride

36

36

36

37

37

Potassium chloride

35

35

40

46

54

Ammonium chloride

24

37

41

55

66


Pragya tested the solubility of three different substances at different temperatures and collected the data as given below (results are given in the following table, as grams of substance dissolved in 100 grams of water to form a saturated solution).

Substance Dissolved

Temperature in K

283

293

313

333

353

Potassium nitrate

21

32

62

106

107

Sodium chloride

36

36

36

37

37

Potassium chloride

35

35

40

46

54

Ammonium chloride

24

37

41

55

66

What is the effect of change of temperature on the solubility of a salt?

Explain the following giving examples:

Saturated solution

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