Quiz 4 of 20

# SS1: Chemistry 2nd Term Theory Questions – Kinetic Theory of Matter & Gas Laws 1

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## Question 1

Convert the following Celsius temperature to Kelvin temperature

(a) 00

Answer = (0 + 273)k = 273k

(b) 1500

Answer =  (150 + 273)k = 423k

(c) 1000

Answer = (100 + 273)k = 373k

(d) 2750

Answer= (275 + 273)k = 548k

(e) -500C

Answer = (-50 + 273)k = 223k

## Question 2

(a) State three Postulates of the Kinetic Theory of Gases

Answer -

(i) Gas molecules move randomly in a straight line colliding with one another and with the walls of the container

(ii) The collision between the gas molecules are perfectly elastic.

(iii) The actual volume occupied by the gas molecules is negligible compared with the volume of the container.

(b) Draw a sketch to illustrate Boyle’s law

Answer -

(c) The volume occupied by Carbon(IV)oxide at 760mmHg is 200cm3. Calculate the volume of the gas, if the pressure is changed to 253mmHg. Assuming the temperature of the system remains constant

Answer -

P1 = 760mmHg

V1 = 200cm3

P1 = 253mmHg

V2 = ?

P1V1 = P2V2

V2    = $$\frac{P_1V_1}{P_2} \\= \frac{760 \; \times \; 200}{253}$$

V2 = 600.79cm3

## Question 3

(a) What do you understand by Standard Temperature and Pressure (s.t.p)

Answer - Standard Temperature and Pressure (s.t.p) – a reference temperature and pressure arbitrarily adopted as standard temperature is 00C or 273k; standard temperature is 760mmHg or 1.01 x 105Nm-2 or 7atm or 101325pa.

(b) Convert to Celsius Temperature

(i) 275K

Answer - -20C

(ii) 318K

Answer -  450C

## Question 4

(a) Draw a pictorial representation of Boyle’s Law

Answer -

(b) The pressure of 100cm3 of Oxygen at 350C is 750mmHg. What will be the volume of the gas if the pressure is reduced to 100mmHg without changing the temperature\

Answer -

V1 = 100cm3 P1 = 750mmHg

V2 = ? P1 = 100mmHg

P1V1 = P2V2

V2 = $$\frac{P_1 V_1}{P_2}\\ = \frac{750 \; \times \; 100}{100} \\ = \scriptsize 750cm^3$$

## Question 1

Convert the following Celsius temperature to Kelvin temperature

(a) 00

Answer = (0 + 273)k = 273k

(b) 1500

Answer =  (150 + 273)k = 423k

(c) 1000

Answer = (100 + 273)k = 373k

(d) 2750

Answer= (275 + 273)k = 548k

(e) -500C

Answer = (-50 + 273)k = 223k

## Question 2

(a) State three Postulates of the Kinetic Theory of Gases

Answer -

(i) Gas molecules move randomly in a straight line colliding with one another and with the walls of the container

(ii) The collision between the gas molecules are perfectly elastic.

(iii) The actual volume occupied by the gas molecules is negligible compared with the volume of the container.

(b) Draw a sketch to illustrate Boyle’s law

Answer -

(c) The volume occupied by Carbon(IV)oxide at 760mmHg is 200cm3. Calculate the volume of the gas, if the pressure is changed to 253mmHg. Assuming the temperature of the system remains constant

Answer -

P1 = 760mmHg

V1 = 200cm3

P1 = 253mmHg

V2 = ?

P1V1 = P2V2

V2    = $$\frac{P_1V_1}{P_2} \\= \frac{760 \; \times \; 200}{253}$$

V2 = 600.79cm3

## Question 3

(a) What do you understand by Standard Temperature and Pressure (s.t.p)

Answer - Standard Temperature and Pressure (s.t.p) – a reference temperature and pressure arbitrarily adopted as standard temperature is 00C or 273k; standard temperature is 760mmHg or 1.01 x 105Nm-2 or 7atm or 101325pa.

(b) Convert to Celsius Temperature

(i) 275K

Answer - -20C

(ii) 318K

Answer -  450C

## Question 4

(a) Draw a pictorial representation of Boyle’s Law

Answer -

(b) The pressure of 100cm3 of Oxygen at 350C is 750mmHg. What will be the volume of the gas if the pressure is reduced to 100mmHg without changing the temperature\

Answer -

V1 = 100cm3 P1 = 750mmHg

V2 = ? P1 = 100mmHg

P1V1 = P2V2

V2 = $$\frac{P_1 V_1}{P_2}\\ = \frac{750 \; \times \; 100}{100} \\ = \scriptsize 750cm^3$$