Scientific and Mathematical Reasoning Flashcards

A solution turns red litmus paper blue. Which of the following is most consistent with this observation?

Answer: The solution contains excess OH⁻ ions

Red litmus turns blue in basic (alkaline) solutions, which have a pH above 7 and excess hydroxide ions.

Three friends run a race. Their finishing times in seconds are 52, 58, 48, 61, and 46. What is the median finishing time?

Answer: 52

Ordered: 46, 48, 52, 58, 61; the middle value (3rd of 5) is 52 seconds.

A chemical reaction produces a gas that extinguishes a burning splint. Which gas was most likely produced?

Answer: Carbon dioxide

Carbon dioxide does not support combustion and will extinguish a burning splint (oxygen relights a glowing splint; hydrogen burns with a squeaky pop).

If the probability of event X occurring is 0.3 and the probability of event Y occurring is 0.5, and the two events are independent, what is the probability that neither X nor Y occurs?

Answer: 0.35

P(not X) = 0.7, P(not Y) = 0.5; P(neither) = 0.7 × 0.5 = 0.35.

A student notices that ice melts faster in a black container than in a white container when both are placed in sunlight. The best scientific explanation is:

Answer: Black surfaces absorb more radiant energy than white surfaces

Dark surfaces absorb more electromagnetic radiation and convert it to heat, accelerating the melting of the ice.

A square has its side length doubled. By what factor does its area increase?

Answer: 4

Area = s²; doubling s gives (2s)² = 4s², so the area increases by a factor of 4.

In a food web, removing the top predator typically leads to:

Answer: Population increase of prey and potential collapse of vegetation

Without top predators, prey populations grow unchecked (trophic cascade), which can overgraze vegetation and destabilize the ecosystem.