CBSE Questions for Class 7 Chemistry Physical And Chemical Changes Quiz 4 - MCQExams.com

Galvanised iron sheets are used in making iron trunks and suitcases.
  • True
  • False
Iron rusts in presence of air and moisture.
  • True
  • False
Stainless steel resists rust formation.
  • True
  • False
Match the columns:

III
(a)Physical change(i)Curdling of milk
(b)Chemical change(ii)Demagnetisation of magnets
(iii)Digestion of food
(iv)Crystallisation of substance
(v)Rusting of iron
  • a: i, ii, iii;       b: iv, v
  • a: ii, iv;          b: i, iii, iv
  • a: ii, iv;          b: i, iii, v
  • a: iii, v;          b: i, ii, iv
Chemical change are characterised by ___________.
  • Formation of new substance
  • Release of energy
  • Absorption of energy
  • Reversible
$$2Mg + O_2 \longrightarrow$$
  • $$MgO$$
  • $$2MgO$$
  • $$MgO_2$$
  • $$2MgO_2$$

Which of the following is not a physical change?
  • Grating cheese
  • Melting cheese
  • Fermenting cheese
  • Mixing two cheese in a bowl
When magnesium is burnt in presence of air, the weight of magnesium:
  • increases
  • decreases
  • does not change
  • increases then decreases
When magnesium ribbon burns in the air, it forms white ash. The chemical name of white ash is:
  • Magnesium dioxide
  • Magnesium hydride
  • Milk of magnesia
  • Magnesium oxide
What is a chemical change?
  • Change in size, shape
  • Change from one substance to another new substance
  • Change in temperature of the substance
  • None of above
During a chemical change :
  • atoms change.
  • atoms recombine to form different substances.
  • a substance remain the same chemically.
  • none of these
Which of the following would not be a physical change?
  • Freezing water to make ice cubes.
  • Melting gold to make jewellery.
  • Burning gasoline in a lawn mower.
  • Boiling water for soup.
Which of the following statements is not correct?
  • In a chemical change, color of the object may change.
  • In a chemical change, heat will always be released.
  • A chemical change always involves a physical change.
  • Rusting of iron becomes faster when humidity is high.

Which of the following is an example of chemical change?
  • Filling up a balloon with hot air.
  • Taking a glass of water and freezing it by placing it in the freezer.
  • A plant collecting sunlight and turning it into food.
  • Your dog ripping up your homework.
All of the following involve a chemical change at a particular temperature except :
  • the formation of HCl from $$H_2$$ and $$Cl_2$$
  • the color change when NO is exposed to air
  • the formation of steam from buring $$H_2$$ and $$CO_2$$
  • the solidification of vegetable oil at low temperatures
  • the odor of $$NH_3$$ when $$NH_4Cl$$ is rubbed together with $$Ca(OH)_2$$ powder.
Sun tanning is a/an :
  • Physical change
  • Chemical change
  • Both a and b
  • None of the above
Which of the following is a physical change?
  • Cutting trees
  • Burning of paper
  • Breakdown of sugars
  • All of above
Rain formation is a
  • Chemical change
  • Physical change
  • No change takes place
  • Gravitational phenomenon
Common chemical changes are :
  • change in temperature
  • formation of precipitate
  • formation of bubbles
  • all of above
Physical change include change in :
  • texture
  • temperature
  • formation of bubbles
  • both a and b
$$H_{2}O_{(l)}\rightleftharpoons H_{2}O_{(g)}$$
What type of change is represented by the equation above?
  • This is a physical change because the equation is balanced.
  • This is chemical change because the equation is balanced.
  • This a physical change because the same compound is represented as both the reactant and product.
  • This a chemical change because the same compound is represented as both the reactant and product.
Boiling water is a _____ change because _____.
  • Physical, the gaseous water produced is chemically identical to the liquid water the process began with
  • Physical, the water was disappeared
  • Chemical, heat was required for the change
  • Chemical, the process produced a gas
Melting of butter is a physical change.
  • True
  • False
Your lab partner mixed two colorless solutions in the test tube. He sees no observable changes in the resulting mixture and is unable to detect any temperature change. Based on these observations, what type of change has taken place?
  • Physical change
  • Chemical change
  • Periodic change
  • None of the above
Which of the following is an example of a physical change?
  •  Mixing of baking soda and vinegar together to cause bubbles and foam.
  •  Falling of a glass cup from the counter and its shattering on the ground.
  • Lighting a piece of paper on fire causing it to bum up and leave ashes.
  • Baking a birthday cake for your mother.
What kind of change is undergone when an electric bulb glows?
  • A physical change
  • A chemical change
  • Both physical and chemical changes
  • A permanent change
State whether true or false:
Heating of sugar solution is a chemical change.
  • True
  • False
Chemical change involves
  • No change in weight of the reacting substance
  • Change in the composition
  • Absorption (or) the release of energy
  • Formation of precipitate
Which of the following is a physical change?
a) Hammering of a red hot iron rod to make a flat sheet.
b) Formation of ice by cooling of water.
c) Rising of water vapors from sea to make clouds.
d) Heating of charcoal in the air to high temperature till it begins to flow.
  • a, b and c
  • b, c and d
  • c, d and a
  • d, a and b
What conditions are required for rusting to take place?
  • Water only
  • Oxygen only
  • Water and oxygen
  • Water and carbon dioxide
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