[2 Mark Questions]

Question 12 Marks

Ruthresh, Hari, Kanishka, and Thahera collected different samples of water from a well, a pond, a river, and underground water. All these samples were sent to a testing laboratory. The test result showed the ratio of hydrogen to oxygen as 1:8.
a. What conclusion would you draw from the above experiment?
b. Which law of chemical combination does it obey?

Answer

1. Water obtained from different sources like a well, a pond, a river, and underground water will always consist of the same two elements hydrogen and oxygen in the ratio of $1: 8$ by mass.
2. It obeys the law of constant proportion.

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Question 22 Marks

Write the chemical formula for the following compounds
a. Aluminium sulphate
b. Silver nitrate
c. Magnesium oxide
d. Barium chloride

Answer

1. Aluminium sulphate $= Al _2\left( SO _4\right)_3$
2. Silver nitrate $= AgNO _3$
3. Magnesium oxide $= MgO$
4. Barium chloride $= BaCl _2$

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Question 32 Marks

Find the valency of the element which is underlined in the following formula.
a. $NaCl$
b. $CO _2$
c. $Al \left( PO _4\right)$
d. $Ba \left( NO _3\right)_2$
e. $CaCl _2$

Answer

a. $\underline{ NaCl }=1$
b. $CO _2=4$
c. $\underline{ Al }\left( PO _4\right)=3$
d. $Ba \left( NO _3\right)_2=2$
e. $CaCl _2=2$

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Question 42 Marks

Write the names of the following compounds.a. $CO$
b. $N _2 O$
c. $NO _2$
d. $PCl _5$

Answer

1. Carbon monoxide.
2. Nitrous oxide
3. Nitrogen dioxide
4. Phosphorous pentachloride

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Question 52 Marks

Write the properties of anode rays.

Answer

Properties of Anode rays:

Anode rays travel in straight lines.
Anode rays are made up of material particles.
Anode rays are deflected by electric and magnetic fields. Since they are deflected towards the negatively charged plate, they consist of positively charged particles.

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Science [2 Mark Questions]

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