Chemistry
Trending Questions
Give an atomic number, atomic symbol, atomic mass of the first 20 elements.
A diver is able to cut through water in a swimming pool. Which property of matter does this activity show?
Explain the characteristics of particles of matter
Liquids generally have lower density as compared to solids. But ice floats on water. Explain why?
Comment on the following properties: (A) Rigidity (B) Compressibility (C) Fluidity (D) Filling a gas container (E) Shape (F) Kinetic energy and (G) density
Which of the following are matter? Chair, air, love, smell, hate, almonds, thought, cold, cold drink, the smell of perfume.
Name all the 118 elements in the periodic table with their symbol, atomic mass and atomic number.
Give two reasons to justify [5 MARKS]
(a) Water at room temperature is a liquid.
(b) An iron almirah is a solid at room temperature.
The smell of hot sizzling food reaches you several meters away, but to get the smell of cold food you have to go close. Explain.
Properties of solid, liquid , gas
What are the factors affecting evaporation?
Barium chloride reacts with aluminium sulfate to give aluminium chloride and a precipitate of barium sulfate.
Translate and balance
Give reasons
A gas fills completely the vessel in which it is kept.
Why does the temperature remain constant during changes of state?
Question 3.2
Write a balanced chemical equation and state symbols for the reaction:
Sodium hydroxide solution (in water) reacts with hydrochloric acid solution (in water) to produce sodium chloride solution and water.
Give reasons for the following observation: The smell of hot sizzling food reaches you several metres away, but to get the smell from cold food you have to go close. Why?
Why does a desert cooler cool better on a hot, dry day ?
A sample of drinking water was found to be severely contaminated with chloroform (CHCl3). Supposed to be carcinogenic in nature. The level of contamination was 15 ppm (by mass).
(i) Express this in percentage by mass.
(ii) Determine the molality of chloroform in the water sample.
Why is ice at 273 K more effective in cooling than water at the same temperature?
In the refining of silver, the recovery of silver from silver nitrate solution involves displacement by copper metal. Write down the reaction involved.
A shiny brown colored element ‘X’ on heating in the air becomes black in color. Name the element ‘X’ and the black colored compound formed.
Translate the following statement into chemical equation and then balance it:
Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.
Define matter?
Question 3 (d)
Give reasons
(d) We can easily move our hand in air but to do the same through a solid block of wood we need a karate expert.
Naphthalene balls disappear with time without leaving any solid. Give reason
Why does ice float on water?
Give two reasons to justify: An iron almirah is a solid at room temperature?
Liquids generally have a lower density as compared to solids. But you must have observed that ice floats on water. Find out why.
