|
(i) Account for the following: 1. White silver chloride turns grey in sunlight
|
|
1
|
17130
|
March 28, 2019
|
|
A silver article generally turns black when kept in the open for a few days. The article when rubbed with toothpaste again starts shining?
|
|
1
|
2831
|
March 28, 2019
|
|
Why do we store silver chloride in dark coloured bottles which are also called as amber bottles?
|
|
1
|
1056
|
March 28, 2019
|
|
Define oxidation and reduction?
|
|
1
|
712
|
March 28, 2019
|
|
What are exothermic and endothermic reactions?
|
|
1
|
960
|
March 28, 2019
|
|
Write any two observations in an activity which may suggest that a chemical reaction has taken place. Give an example in support of your answer?
|
|
1
|
5061
|
March 28, 2019
|
|
When you mix solutions of lead (II) nitrate and potassium iodide
|
|
1
|
35298
|
March 28, 2019
|
|
(i) Name the products formed when sodium hydrogen carbonate is heated
|
|
1
|
859
|
March 28, 2019
|
|
Define a combination reaction. Give one example of a combination reaction which is also exothermic
|
|
1
|
1931
|
March 28, 2019
|
|
(i) What is observed when a solution of potassium iodide is added to a solution of lead nitrate taken in a test tube?
|
|
1
|
4388
|
March 28, 2019
|
|
(a) What is the colour of ferrous sulphate crystals? How does this colour change after heating?
|
|
1
|
2786
|
March 28, 2019
|
|
What is an oxidation reaction? Identify in the following reaction
|
|
1
|
1067
|
March 28, 2019
|
|
Why do silver articles turn black and copper items turn green after some time?
|
|
1
|
2339
|
March 28, 2019
|
|
Give an example of a decomposition reaction. Describe an activity to illustrate such a reaction by heating?
|
|
1
|
2598
|
March 28, 2019
|
|
On what basis is a chemical equation balanced?
|
|
1
|
5086
|
March 28, 2019
|
|
In electrolysis of water, why is the volume of gas collected over one electrode is double that of gas collected over the other electrode
|
|
1
|
4959
|
March 28, 2019
|
|
Give an example of decomposition reaction
|
|
1
|
684
|
March 28, 2019
|
|
Balance the following chemical equation:
|
|
1
|
626
|
March 28, 2019
|
|
Which of the following reactions have a positive ΔSrxn? Check all that apply
|
|
0
|
1417
|
March 24, 2018
|
|
Draw the remaining product of the following reaction
|
|
0
|
2988
|
March 24, 2018
|
|
Which of the following molecules contain sphingosine? Select all that apply
|
|
0
|
6189
|
March 20, 2018
|
|
Draw the products of the complete of anacetal. Draw all products of the reaction
|
|
0
|
7191
|
March 20, 2018
|
|
The reaction' A+B--> C+D rate=k[A][B]2
|
|
0
|
640
|
March 19, 2018
|
|
NH4Br --> acid LiNO3 --> neutral K2SO3 --> basic KCl --> neutral Na2S --> basic
|
|
0
|
950
|
March 19, 2018
|
|
Consider this reaction and its rate law. 3A + 2B --> products
|
|
0
|
11705
|
March 17, 2018
|
|
Name the acid present in an ant sting and give its chemical formula
|
|
0
|
2908
|
March 16, 2018
|
|
Which plants grow well over the largest range of pH values?
|
|
0
|
3257
|
March 16, 2018
|
|
What is ‘baking powder’? How does it make the cake soft and spongy?
|
|
0
|
9155
|
March 16, 2018
|
|
The pH of soil A is 7.5 while that of soil B is 4.5. Which of the two soils should be treated with powdered chalk to adjust its pH and why?
|
|
0
|
16426
|
March 16, 2018
|
|
Name the gas evolved when dilute HCl reacts with sodium hydrogen carbonate. How is it recognised?
|
|
0
|
3554
|
March 16, 2018
|