**Study of Gas Laws Exe-7 Structured Answer Chemistry** Class-9 ICSE Selina Publishers Solutions Chapter-7. Step By Step ICSE Selina Concise Solutions of Chapter-7 **Study of Gas Laws** with All Exercise including MCQs, Very Short Answer Type, Short Answer Type, Long Answer Type, Numerical and Structured/Application Questions Solved **. **Visit official Website CISCE for detail information about ICSE Board Class-9.

**Study of Gas Laws Exe-7 Structured Answer Chemistry Class-9 ICSE Concise Selina Publishers**

Board | ICSE |

Publications | Selina Publication |

Subject | Chemistry |

Class | 9th |

Chapter-7 | Study of Gas Laws |

Book Name | Concise |

Topics | Solution of Exercise – 7 Structured/Application Answer Type |

Academic Session | 2023-2024 |

**E. Exercise – 7 Structured/Application Answer Type**

**Study of Gas Laws Class-9 Chemistry Concise Solutions **

**Page-133**

**Question 1.**

(a) State the law verified by the following figure:

(b) Draw P.V. isothermal for the above law.

**Answer:**

(a) Boyle’s law — It states that the volume of a given mass of a dry gas is inversely proportional to its pressure at a constant temperature i.e., P_{1}V_{1} = P_{2}V_{2}

(b) P.V. isothermal for Boyle’s law is shown below :

**Question 2.**

(a) State the law which the following graph verifies.

(b) Derive the mathematical expression for it.

(c) Give one application/use where the above law is employed.

**Answer:**

(a) Charles’ law — It states that pressure remaining constant, the volume of a given mass of dry gas increases or decreases by 1/273 of its volume at 0°C for each 1°C increase or decrease in temperature, respectively.

(b) Let V_{0} be the volume of a fixed mass of a gas at 0°C and let V be its volume at temperature t°C at constant pressure. Then according to Charles’ law,

V = Vo + (Vo/273)t (when P is constant)

V = Vo (1 + t/273)

= Vo (273 + t)/273

V =V0/273 T where T = 273 + t

For a given mass of a gas,

V0/273 = constant

∴ V = k x T (where k is constant)

or V α T and V/T = K

Suppose a gas occupies V1 cm3 at T1 temperature and V2 cm3 at T2 temperature, then by Charles law,

V1 α T1

or V1 = kT1 (k is constant)

or

V1/T1 = k and

V2 α T2

or V2/T2 = k

∴ V1/T1 = V2/T2 = k (at constant pressure)

(c) Volume of a given mass of a gas is directly proportional to its temperature, hence, density decreases with an increase in temperature. This is the reason that hot air is filled into balloons used for meteorological purposes.

**Question 3.**

**Plot V versus absolute T (K) by the given data:**

Temperature | Volume in litres |
---|---|

27°C | 4.8 |

77°C | 5.6 |

127°C | 6.4 |

177°C | 7.2 |

227°C | 8.0 |

(a) The graph between V and T is a …………… .

(b) Check whether the line passes through the origin.

(c) Which law is obeyed.

**Answer:**

Converting temperature to Kelvin Scale :

Temp (°C) |
Temp (K) |
Volume (litres) |
---|---|---|

27 | 300 | 4.8 |

77 | 350 | 5.6 |

127 | 400 | 6.4 |

177 | 450 | 7.2 |

227 | 500 | 8.0 |

Graph of V versus absolute T is shown below :

(a) The graph between V and T is a ** straight line**.

(b) Yes, as we can see in the graph, the line passes through the origin.

(c) Charles’ law

— : End of** Study of Gas Laws Exe-7 Structured Answer** Class-9 ICSE Chemistry Solutions :–

Return to **Return to Concise Selina ICSE Chemistry Class-9 **

Thanks

Please share with your friends