Chemistry Reactions

A chemical reaction has taken place can be represented by which of the following condition?

• (i) Evolution of gas

• (ii) Heat released

• (iii) Change in color

• (iv) All the above

Tags

NGSS.MS-PS1-2

A chemical equation is said to be balanced if number of

• (i) Compounds are same in both side

• (ii) Molecules are same in both side

• (iii) Number of atoms is same in both side

• (iv) Number of electrons are same in both side

Tags

NGSS.MS-PS1-5

Write values of a,b and c if following chemical reaction is balanced . aMg + bO2 → cMgO

• a=2, b=1, c=2

• a=1, b=1, c=2

• a=2, b=1, c=1

• a=2, b=2, c=2

Tags

NGSS.MS-PS1-5

Calcium oxide reacts with water to form calcium Hydroxide. Which type of reaction is this?

• (i) Combination and endothermic reaction

• (ii) Combination and exothermic reaction

• (iii) Decomposition and Endothermic reaction

• (iv) Decomposition and exothermic reaction

Tags

NGSS.MS-PS1-4

On thermal decomposition of lead nitrate, nitrogen dioxide gas is evolved. How it presence can be verified?

• It will turn lime water milky

• Rotten egg odour

• Brown fumes can be observed

• Reddish fume is observed

Tags

NGSS.MS-PS1-2

Which of the following statements about the given reaction are correct?3Fe (s) + 4H₂O (g) → Fe₃O₄ (s) + 4 H₂ (g)(i) Iron metal is getting oxidised(ii) Water is getting reduced(iii) Water is acting as reducing agent(iv) Water is acting as oxidising agent

• (i), (ii) and (iii)

• (ii) and (iv)

• (i), (ii) and (iv)

• (ii) and (iv)

Tags

NGSS.MS-PS1-5

Three beakers labelled as A, B and C each containing 25 ml of water were taken. A small amount of NaOH, anhydrous CuSO4 and NaCl were added to the beakers A, B and C respectively. It was observed that there was an increase in the temperature of the solution contained in beakers A and B, whereas in case of beaker C, the temperature of the solution falls. Which one of the following statement(s) is (are) correct?(i) In beakers A and B, exothermic process has occurred.(ii) In beakers A and B, endothermic process has occuBftd.(iii) In beaker C exothermic process has occurred.(iv) In beaker C endothermic process has occurred.

• (i) only

• (ii) only

• (i) and (iv)

• (iv), (ii) and (iii)

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

A chemical reaction has taken place in which of the following process?

• (i) Ice melts into water

• (ii) A wet shirt got dried in sunlight

• (iii) A brown layer is formed over iron rod kept in air

• (iv) Sugar getting dissolved in water

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

The chemical formula of lead sulphate is

• (a) Pb2SO4

• (b) Pb(SO4)2

• (c) PbSO4

• (d) Pb2(SO4)3

Tags

NGSS.MS-PS1-1

Chemically rust is

• (a) hydrated ferrous oxide

• (b) only ferric oxide

• (c) hydrated ferric oxide

• (d) none of these

Tags

NGSS.MS-PS1-1