Year :
2017
Title :
Chemistry
Exam :
JAMB Exam
Paper 1 | Objectives
41 - 49 of 49 Questions
| # | Question | Ans |
|---|---|---|
| 41. |
A particle that contains 9 protons, 10 neutrons and 10 electrons is A. positive ion B. neutral atom of a metal C. neutral atom of a non-metal D. negative ion Detailed Solutionprotons = 9neutrons = 10 electrons = 10 Electronic configuration = 2, 8 Ground state Electronic configuration=2, 7 It means that the atom has gained an electron thereby making it have a negative ion. When an atom donates an electron, it becomes positively charged. When an atom accepts an electron, it becomes negatively charged There is an explanation video available below. |
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| 42. |
Ethene is prepared industrially by A. Reforming B. Polymerization C. Distillation D. Cracking |
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| 43. |
Calculate the amount in moles of a gas which occupies 10.5 dm3 at 6 atm and 30oC [R = 0.082 atm dm3 K-1 mol-1] A. 2.536 B. 1.623 C. 4.736 D. 0.394 Detailed SolutionFor an ideal gas PV = nRTAmount in moles = n Volume v = 10.5dm3 Pressure P = 6atm Temperature T = 30°C + 273 = 303k R, Gas constant = 0.082 atmdm3k-1 mol Recall from ideal gas equation pv = nRT n = \(\frac{RV}{RT}\) n = \(\frac{6 \times 10.5}{0.082 \times 303}\) n= 2.536mol There is an explanation video available below. |
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| 44. |
If 100cm3 of oxygen pass through a porous plug is 50 seconds, the time taken for the same volume of hydrogen to pass through the same porous plug is? [O = 16, H = 1] A. 10.0s B. 12.5s C. 17.7s D. 32.0s |
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| 45. |
Due to the high reactivity of sodium, it is usually stored under A. water B. mercury C. paraffin D. phenol |
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| 46. |
The furring of kettles is caused by the presence in water of A. calcium hydrogentrioxocarbonate (IV) B. calcium trioxocarbonate (IV) C. calcium tetraoxosulphate (VI) D. calcium hydroxide |
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| 47. |
Water for town supply is chlorinate to make it free from A. bad colour B. bacteria C. temporary hardness D. permanent hardness |
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| 48. |
Ca(OH)2(s) + 2NH4Cl(s) → CaCl2(s) + 2H2O(l) + X. In the reaction above X is A. NO2 B. NH3 C. N2O D. NO2 Detailed SolutionBalancing the chemical equation.Ca[OH]2 + 2NH4Cl → CaCl2 + 2H2O + 2NH3 X = NH3 There is an explanation video available below. |
|
| 49. |
X(g) + 3Y(g) ---- 2z(g) H = +ve. if the reaction above takes place at room temperature, the G will be A. negative B. zero C. positive D. indeterminate Detailed Solution\(\begin{array}{c|c}\text{Enthalpy Change [ΔH]} & \text{Entropy Change [ΔS]} & \text{Gibbs free Energy[ΔG]} \\ \hline \text{Positive} & \text{Positive} & \text{depends on T, may be + or -} \\ \hline \text{Negative} & \text{Positive} & \text{always negative} \\ \hline \text{Negative} & \text{Negative} & \text{depends on T, may be + or -} \\ \hline \text{Positive} & \text{Negative} & \text{always positive} \end{array}\) ΔG= ΔH − TΔS. To determine whether ΔG will be positive or negative, the value of ΔH( |
| 41. |
A particle that contains 9 protons, 10 neutrons and 10 electrons is A. positive ion B. neutral atom of a metal C. neutral atom of a non-metal D. negative ion Detailed Solutionprotons = 9neutrons = 10 electrons = 10 Electronic configuration = 2, 8 Ground state Electronic configuration=2, 7 It means that the atom has gained an electron thereby making it have a negative ion. When an atom donates an electron, it becomes positively charged. When an atom accepts an electron, it becomes negatively charged There is an explanation video available below. |
|
| 42. |
Ethene is prepared industrially by A. Reforming B. Polymerization C. Distillation D. Cracking |
|
| 43. |
Calculate the amount in moles of a gas which occupies 10.5 dm3 at 6 atm and 30oC [R = 0.082 atm dm3 K-1 mol-1] A. 2.536 B. 1.623 C. 4.736 D. 0.394 Detailed SolutionFor an ideal gas PV = nRTAmount in moles = n Volume v = 10.5dm3 Pressure P = 6atm Temperature T = 30°C + 273 = 303k R, Gas constant = 0.082 atmdm3k-1 mol Recall from ideal gas equation pv = nRT n = \(\frac{RV}{RT}\) n = \(\frac{6 \times 10.5}{0.082 \times 303}\) n= 2.536mol There is an explanation video available below. |
|
| 44. |
If 100cm3 of oxygen pass through a porous plug is 50 seconds, the time taken for the same volume of hydrogen to pass through the same porous plug is? [O = 16, H = 1] A. 10.0s B. 12.5s C. 17.7s D. 32.0s |
|
| 45. |
Due to the high reactivity of sodium, it is usually stored under A. water B. mercury C. paraffin D. phenol |
| 46. |
The furring of kettles is caused by the presence in water of A. calcium hydrogentrioxocarbonate (IV) B. calcium trioxocarbonate (IV) C. calcium tetraoxosulphate (VI) D. calcium hydroxide |
|
| 47. |
Water for town supply is chlorinate to make it free from A. bad colour B. bacteria C. temporary hardness D. permanent hardness |
|
| 48. |
Ca(OH)2(s) + 2NH4Cl(s) → CaCl2(s) + 2H2O(l) + X. In the reaction above X is A. NO2 B. NH3 C. N2O D. NO2 Detailed SolutionBalancing the chemical equation.Ca[OH]2 + 2NH4Cl → CaCl2 + 2H2O + 2NH3 X = NH3 There is an explanation video available below. |
|
| 49. |
X(g) + 3Y(g) ---- 2z(g) H = +ve. if the reaction above takes place at room temperature, the G will be A. negative B. zero C. positive D. indeterminate Detailed Solution\(\begin{array}{c|c}\text{Enthalpy Change [ΔH]} & \text{Entropy Change [ΔS]} & \text{Gibbs free Energy[ΔG]} \\ \hline \text{Positive} & \text{Positive} & \text{depends on T, may be + or -} \\ \hline \text{Negative} & \text{Positive} & \text{always negative} \\ \hline \text{Negative} & \text{Negative} & \text{depends on T, may be + or -} \\ \hline \text{Positive} & \text{Negative} & \text{always positive} \end{array}\) ΔG= ΔH − TΔS. To determine whether ΔG will be positive or negative, the value of ΔH( |