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JAMB UTME - Chemistry - 2013

Question 1 Rapport

The constituent of air that acts as a diluent is

nitrogen

carbon (IV) oxide

noble gases

oxygen

Détails de la réponse

The constituent of air that acts as a diluent is nitrogen. Diluent refers to a substance that is added to a gas or liquid to reduce its concentration. In the case of air, nitrogen is the most abundant gas and makes up about 78% of the air we breathe. The other gases present in air such as oxygen, carbon dioxide, and noble gases make up the remaining 22%. Nitrogen, being an inert gas, does not react with other elements, which makes it an ideal diluent in air. It helps to lower the concentration of reactive gases, making it easier for us to breathe and for combustion reactions to occur safely.

Lisez la note de cours sur Air (JAMB)

Voir la réponse

Question 16 Rapport

The radioactive emission with the least ionization power is

α−particles

X-rays

γ - r a y s

β−rays

Détails de la réponse

The radioactive emission with the least ionization power is gamma (γ) radiation. Gamma radiation is a type of electromagnetic radiation that has the highest frequency and shortest wavelength among all types of radiation. While it is highly penetrating and can cause damage to biological tissues, it has the least ionization power because it carries no electric charge and does not interact strongly with matter. This means that gamma radiation can easily pass through materials without being deflected or slowed down, and it takes a lot of energy to ionize atoms or molecules through gamma radiation. In comparison, alpha and beta radiation are particles that carry an electric charge and interact more strongly with matter, making them more ionizing than gamma radiation.

Lisez la note de cours sur Structure Of The Atom (WAEC)

Lisez la note de cours sur Periodic Chemistry (Nigeria Only) (WAEC)

Structure Of The Atom

Periodic Chemistry (Nigeria Only)

Voir la réponse

Question 17 Rapport

The rate of diffusion of a gas Y is twice that of Z If the relative molecular mass of Y is 64 and the two gases diffuse under the same conditions, find the relative molecular mass of Z

32

4

8

16

Détails de la réponse

\sqrt{y}

= 2x

\sqrt{Z}

= x

\frac{r z}{r y}

=

\sqrt{\frac{m y}{m z}}

$\frac{2 x}{x}$ = $\sqrt{\frac{64}{m z}}$
$\frac{4}{1}$ = $\frac{64}{m z}$

mz = $\frac{64}{4}$
mz = 16

Lisez la note de cours sur Kinetic Theory Of Matter And Gas Laws (JAMB)

Kinetic Theory Of Matter And Gas Laws

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Question 42 Rapport

10.0 dm3 of water was added to 2.0 mol dm-3 of 2.5dm3 solution of HCl. What is the concentration of the final solution in mol dm-3?

0.4

8.0

2.0

0.5

Détails de la réponse

C1V1 = C2V2

C2 = $\frac{C_{1} V_{1}}{V_{2}}$

= $\frac{2.0 \times 2.5}{12.5}$

= 0.4mol/dm-3

Lisez la note de cours sur Kinetic Theory Of Matter And Gas Laws (JAMB)

Kinetic Theory Of Matter And Gas Laws

Voir la réponse

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