Question

Sleeping Sitting 100 Wallona 200 500 1 Swirnering Running 750 24h C. 5.15 h D 10h 17. This is not a chemical property A Titanium metal can be drawn into thin wires B Silver metal shows no sign of reaction when placed in hydrochloric acid C. Copper metal becomes greenish-blue on prolonged exposure to the atmosphere D. Beryllium metal when inhaled in a finely divided form, can produce serious lung disease 18 This is not a physical change: A gold metal hammered into thin sheets of gold leaf B water poured from a carale into a tumbler O magnesium nibbon cut into small pieces and placed in a test-lube D. milk exposed to the atmosphere develops a foul odor 19 This is not a pure substance A graphite (pencl lead B water c sea water D. carbon dioxide 20. This is not a homogeneous mixture A brass B bronze C. Steel Dtable sugar 21 This is not a compound A glucose B. carbon dioxide C. baking soda D. pencil lead

17 -21

Answer 1

Answer:-

(17)-

As we know that chemical property of the substance is that property in which chemical composition of the substance is permanently changed whenever changed is carried out. therefore Titanium metal can be drawn into thin wires which shows the ductile property of the titanium which is physical property of the titanium in which chemical composition of the titanium does not changed and only shape of titanium metal changed. whereas silver metal (Ag) has no sign of reaction when placed in HCl is chemical property of Ag , there is no sign of reaction because Ag metal is covered with AgCl , which is formed by the reaction Ag and HCl.

Also we know that copper (Cu) metal becomes greenish blue on prolonged exposure to the atmosphere because of the formation of copper carbonate and copper hydroxide therefore it is a chemical property.

Beryllium (Be) when inhaled, can produced serious lung disease is also a chemical property.

Therefore correct option is 'A' i.e Titanium metal can be drawn into thin wires which is not a chemical property.

(18)-

As we know that chemical change of the substance in which chemical composition of the substance is permanently changed whenever changed is carried out whereas physical change of the substance in which only form of the substance is temporarily changed whenever changed is carried out. therefore

gold metal hammered into thin sheets of gold leaf is physical change in which only shape of the gold metal changed not chemical composition of gold.

water poured from a carate into a tumbler is physical change in which only shape of the water changed not chemical composition of water.

Magnesium ribbon cut into a small pieces and placed into a test tube is physical change in which only shape of the magnesium metal changed not chemical composition of magnesium metal.

Milk exposed to the atmosphere develops a foul odor is chemical change in which chemical composition of milk is changed.

Therefore correct option is 'D' i.e Milk exposed to the atmosphere develops a foul odor which is not a physical change.

(19)-

As we know that graphite of the pencil lead is the pure substance because it is made up of C-atom. Also we know that water (H₂O) and carbon dioxide (CO₂) are also pure substance but sea water is not a pure substance because generally it is a mixture of water (H₂O) and salt (NaCl).

Therefore correct option is 'C' i.e sea water.

(20)-

As we know that table sugar i.e sucrose which is a compound having chemical formula of C₁₂H₂₂O₁₁ .Sucrose has fixed proportions of C, H and O therefore it is not a mixture whereas brass , bronze , steel are example of homogeneous mixture because they are made up two or more metals in different proportions.

Therefore correct option is 'D' i.e table sugar.

(21)-

As we know that glucose is a compound having chemical formula of C₆H₁₂O₆ . Also we know that carbon dioxide (CO₂) and baking soda (NaHCO₃) are also compound but pencil ''lead'' is not a compound it is a mixture of clay (SiO₂) and graphite.

Therefore correct option is 'D' i.e pencil ''lead''.