Matter in Our Surroundings- Blog 6

CHEMISTRY

Chapter 1: MATTER IN OUR SURROUNDINGS

HELLO STUDENTS.

Today we will be attempting the Questions in the Exercises page no. 12

Question 1. We have done one such question in the previous blog.

(Please refer to In-text question 1)

Question 2. If you are able to do this ☝ then you just have to do the opposite of it.

Question 3:Give reason for the following observations.

(a) Naphthalene balls disappear with time without leaving any solid. 

(b) We can get the smell of perfume sitting several meters away. 

Solution: (a) Think of the process where a solid disappears into gas meaning changes directly into gaseous state.

So, the naphthalene balls disappear with time as they show _________ due to heat of surroundings.

(b) What makes the gas particles to move through a distance?

Question 4:Arrange the following substances in increasing order of forces of attraction between the particles-water, sugar, oxygen.

Solution:The forces of attraction are strongest in solids and weakest (or negligible) in case of gases. Sugar is a solid, water is in liquid form and oxygen is a gas.

So, the order of forces of attraction is ____________

Question 5:What is the physical state of water at

(a) 25°C (b) 0°C (c) 100°C?

Solution: At zero °C temperature water (liquid) get starts to convert into its solid form (ice) and at 100°C temperature water (liquid) starts to change into water vapours. Between 0° to 100°C it remains in liquid state.

Thus, at (a)________ (b)________ (c)________ (matter can be of two states or at transition state at a temperature)

Question 6:Give two reasons to justify

(a) Water at room temperature is a liquid.

(b) An iron almirah is a solid at room temperature.

Solution: (a) What characteristics of liquid does water has at room temperature. E.g. tendency to flow, it takes the shape of the container, but its volume remains the same.

(b) What characteristics of solid does the almirah has at room temperature. E.g. its shape and volume are definite, hardness, rigidity and its density.

Question 7:Why is ice at 273 K more effective in cooling than water at the same temperature? 

Solution: 273 K (0℃)

What is the energy water has in addition but ice does not?

Question 8:What produces more severe burns, boiling water or steam?

Solution:Steam causes more severe burns than boiling water. The reason is that it releases the extra amount of heat called ___________

Question 9:Name A, B, C, D, E and F in the following diagram showing change in its state.

Solution : I hope this is the easiest. Please refer to Blog 2 or NCERT textbook page no. 8 figure 1.9

THANK YOU!

Please write in the comments section for any queries.

WE ARE NOW DONE WITH THE LESSON.