Check: MCQ | A+ Score Assured
1.
The chemical reaction between HCl(aq) and NH3(aq) is represented above. A
student combines equimolar amounts of HCl(aq) and NH₃(aq), both solutions
initially at 24°C, in a coffee-cup calorimeter. The student observes that the
mixture reaches a temperature of 28°C. Based on the experimental results,
which of the following can be concluded about the reaction? - ✔✔C. It is an
exothermic process, because energy is released by the reaction and is gained by
the reaction mixture.
2.
When pellets of NaOH(s) are added to a flask of water, it is observed that the
temperature of the water increases as the pellets dissolve. Which of the
following claims about the observed dissolution of NaOH(s) in water is most
accurate? - ✔✔C. It is an exothermic process because heat energy is absorbed
by the water as the NaOH(s) dissolves in it.
3.
1|Page
©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025.
, An advertisement for a commercial hand warmer claims that the hand warmer
works because a chemical reaction in the hand warmer draws out the body's
own natural heat, causing a warming effect. Which of the following states the
accuracy of the claim in the advertisement and best provides a correct scientific
justification of the claim? - ✔✔A. The advertisement's claim is inaccurate
because heat flowing from the hands to the warmer would only happen if the
chemical reaction was endothermic, which would cause the hands to feel
colder.
4.
A student carefully drops a 9.0g solid Zn pellet initially at 50.0°C into an
insulated cup containing 30.0g of water at 27.8°C. The student predicts that the
temperature of the water will increase after the pellet is added. Which of the
following statements is the best justification for the student's prediction? -
✔✔B. Collisions between the water molecules and the surface of the Zn pellet
will result in the transfer of energy, increasing the average kinetic energy of the
water molecules.
5.
Two aqueous solutions of equal volume and concentration were kept in flasks
and held at different temperatures. The two solutions were combined in a
2|Page
©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025.