A Water
B Liquid nitrogen
C Ethanol
D Dry ice (solid CO2)
Explanation: Dry ice (solid CO2) sublimes at low temperature and is used as a refrigerant.
Explanation: From 2H2 + O2 to 2H2O, 4 moles of H2 produce 4 moles of H2O since the ratio is 1:1.
A I > Br > Cl > F
B F > Br > Cl > I
C Cl > F > Br > I
D F > Cl > Br > I
Explanation: Electronegativity decreases down a group, so F > Cl > Br > I.
A Zn + CuSO4 to ZnSO4 + Cu
B 2Na + Cl2 to 2NaCl
C CaO + H2O to Ca(OH)2
D 2Al + Fe2O3 to Al2O3 + 2Fe
Explanation: The thermite reaction between aluminium and iron oxide produces molten iron used in welding.
A Hydrogen
B Oxygen
C H2S
D SO2
Explanation: Copper reduces concentrated H2SO4, producing SO2 gas along with CuSO4 and water.
Explanation: In peroxides such as H2O2, oxygen has an oxidation state of -1 instead of the usual -2.
A NaCl
B Na2CO3
C NaHCO3
D NaNO2
Explanation: Sodium nitrite (NaNO2) is used as a preservative in cured meats to prevent bacterial growth.
A CH3OH
B CH3COOH
C CH3CHO
D CH3OCH3
Explanation: Dimethyl ether (CH3OCH3) has an oxygen atom bonded to two alkyl groups, characterizing an ether.
A Ethanol
B Chloroform
C Acetone
D Iodoform
Explanation: Iodoform (CHI3) has mild antiseptic properties and is used on wounds and burns.
Explanation: Be has a filled 2s orbital, making it more stable and harder to ionize than adjacent elements.
A Newton
B Joule
C Pascal
D Watt
Explanation: Newton is the SI unit of force, defined as kg m/s2.
A 9.8 m/s2
B 8.9 m/s2
C 10.2 m/s2
D 11.0 m/s2
Explanation: Standard acceleration due to gravity is 9.81 m/s2.
A Speed
B Mass
C Force
D Energy
Explanation: Force has both magnitude and direction, making it a vector.
A F = ma
B F = mv
C F = m/a
D F = v/a
Explanation: Newton\'s Second Law states force equals mass times acceleration.
A 15 kg m/s
B 8 kg m/s
C 1.67 kg m/s
D 0.6 kg m/s
Explanation: Momentum p = mv = 5 x 3 = 15 kg m/s.
A 50 J
B 2 J
C 15 J
D 0.5 J
Explanation: Work W = F x d = 10 x 5 = 50 J.
A KE = 1/2 mv2
B KE = mgh
C KE = mv
D KE = ma2
Explanation: Kinetic energy equals one-half times mass times velocity squared.
A Zero acceleration
B Constant velocity
C Centripetal acceleration
D Tangential acceleration
Explanation: Circular motion requires centripetal acceleration toward the center.
A 11.2 km/s
B 7.9 km/s
C 15.5 km/s
D 3.2 km/s
Explanation: Escape velocity from Earth is approximately 11.2 km/s.
A Opposite to the direction of motion
B In the direction of motion
C Perpendicular to the surface
D Randomly
Explanation: Friction always opposes the relative motion between surfaces.