a drop of one of these substances rapidly turns litmus dye from blue to red what substance is it

HESI A2

Chemistry Hesi A2

1. Which substance causes a drop to rapidly turn litmus dye from blue to red?

A. Milk
B. Sea water
C. Ammonia
D. Lemon juice

Correct answer: D

Rationale: Lemon juice is the correct answer as it is acidic in nature. Acids like lemon juice release hydrogen ions when dissolved in water, which causes litmus dye to change color from blue to red. Milk (Choice A) is neutral, sea water (Choice B) is slightly alkaline, and ammonia (Choice C) is a base. Therefore, these substances do not cause litmus dye to change from blue to red.

2. A man is reading. He reads two chapters a day. How long will it take if there are 6 pages per chapter and 798 pages total?

A. 66 & 1/2
B. 399
C. 75 & 1/2
D. 133

Correct answer: A

Rationale: First, calculate how many pages the man reads per day. Since he reads two chapters a day and each chapter has 6 pages: 2 chapters/day × 6 pages/chapter = 12 pages/day Now, divide the total number of pages by the number of pages he reads per day: 798 pages ÷ 12 pages/day = 66 1/2 days Thus, it will take him 66 & 1/2 days to finish the book. Therefore, the correct answer is A. 66 & 1/2. Choices B, C, and D are incorrect as they do not correspond to the correct calculation based on the given information.

3. How many kilograms are there in 11 pounds?

A. 5 kilograms
B. 5.5 kilograms
C. 22.2 kilograms
D. 24.2 kilograms

Correct answer: B

Rationale: To convert pounds to kilograms, you can use the conversion factor: 1 pound is approximately equal to 0.453592 kilograms. Therefore, 11 pounds is equal to 11 * 0.453592 = 4.989512, which is approximately 5.5 kilograms. The correct answer is 5.5 kilograms. Choice A is incorrect as it rounds down and doesn't account for the decimals in the conversion. Choices C and D are significantly higher than the correct answer and are clearly incorrect conversions.

4. What charge do Group IIA elements typically have?

A. 1
B. +2
C. -3
D. 0

Correct answer: B

Rationale: Group IIA elements belong to the alkaline earth metals group in the periodic table. These elements typically have a charge of +2 because they readily lose two electrons to achieve a stable electron configuration. Therefore, the correct answer is B - +2. Choice A (1) is incorrect because Group IIA elements lose two electrons, not one. Choice C (-3) is incorrect because Group IIA elements do not gain electrons to have a negative charge. Choice D (0) is incorrect because Group IIA elements do lose electrons and have a positive charge, not a neutral charge.

5. Express the ratio of 13:60 as a percentage.

A. 19.50%
B. 21.67%
C. 25.50%
D. 31%

Correct answer: B

Rationale: To express the ratio 13:60 as a percentage, calculate the decimal form of the ratio by dividing 13 by 60: 13/60 ≈ 0.2167. Next, convert this decimal to a percentage by multiplying by 100: 0.2167 x 100 = 21.67%. Choice A, 19.50%, is incorrect as it does not accurately represent the ratio. Choice C, 25.50%, and Choice D, 31%, are also incorrect calculations of the percentage equivalent of the ratio 13:60.