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Chemistry Past Questions

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27 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10

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27 questions

Question 1 of 7 27 total questions

Question 11

waec 2006

Considered the reaction: H⁺_(aq) + OH ^- _(aq) → H₂O
_(l). The energy change taking place in the reaction above is enthalpy of

Aformation

Bhydration

Cneutralization

Dsolution

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Question 12

waec 2006

Consider the reaction represented by the equation. 2NaHCO_3(s) \(\rightarrow\) 2Na₂CO _3(S) + CO _2(g) + H₂O_(g) what volume of carbon (IV)oxide at s.t.p is evolved when 0. 5 moles of NaHCO₃ is heated? [Molar volume = 22.4 dm³ at s.t. p]

A1.12dm³

B2.24dm³

C5.6dm³

D56.0dm³

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Question 13

waec 2006

If 20 cm3 of distilled water is added to 80cm 3 of 0. 50 mol dm-3 hydrochloric acid, the new concentration of the acid will be

A0.10mol dm^-3

B0.20mol dm^-3

C0.40mol dm^-3

D2.00mol dm^-3

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Question 14

waec 2006

If 1 mole of sodium contains 6 x 10²³ atoms, how many atoms are contained in 0.6 g of sodium? [Na = 23]

A1.56 x 10²³

B1.56 x 10²²

C3.6 x 10²³

D3.6 x 10²²

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Question 15

waec 2006

An atom ²³⁸₉₂X decays by alpha particle emission to give an atom Y. The atomic number and mass number of Y are

A90 and 234 respectively

B91 and 238 respectively

C92 and 236 respectively

D93 and 238 respectively

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Question 16

waec 2006

An element X has isotopic masses of 6 and 7. if the relative abundance is 1 to 12.5 respectively, what is the relative atomic mass of X?

A6.0

B6.1

C6.9

D7.0

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Question 17

waec 2006

How many orbitals are in the d-sub shell?

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