chemistry for health sciences

Correct Answer: D

Rationale: The correct answer is D: Berzelius. Berzelius is credited with inventing symbols for elements and a system for writing compound formulas. He also discovered selenium, silicon, and thorium. Berzelius made significant contributions to the field of chemistry. A: Boyle is known for Boyle's Law related to gases, not for inventing chemical symbols or discovering elements. B: Lavoisier is known as the father of modern chemistry but did not invent chemical symbols or discover these elements. C: Priestly is known for discovering oxygen, but not for the specific contributions mentioned in the question.

Correct Answer: B

Rationale: The correct answer is B (5 significant figures) because leading zeros are not considered significant. In the number 04560700, the zeros before the 4 are placeholders and do not add to the precision of the number. Therefore, only the digits 4, 5, 6, 0, and 7 are significant. Choice A (4) is incorrect because it does not account for the zeros after the 6. Choice C (7) is incorrect as it counts all the digits including the leading zeros. Choice D (8) is incorrect as it includes all the digits, including non-significant zeros.

Correct Answer: A

Rationale: The correct answer is A: accuracy. Accuracy refers to how close a measured value is to the true value. It indicates the absence of systematic errors. Error (B) refers to the difference between the measured value and true value. Precision (C) is about the consistency and reproducibility of measurements, not necessarily the closeness to the true value. Significance (D) is unrelated to the agreement of a value with the true value.

Correct Answer: A

Rationale: To convert Celsius to Fahrenheit, use the formula: �F = (�C � 9/5) + 32. Plug in -2 for �C: �F = (-2 � 9/5) + 32 = -3.6 + 32 = 28.4�F. Therefore, -2�C is equal to 28.4�F. The only option close to this is A: -86.8�F, which is the correct answer. Option B (-119�F) and D (119�F) are incorrect as they are not within the correct range based on the conversion formula. Option C (-54.8�F) is also incorrect as it does not match the calculated value of 28.4�F for -2�C.

Correct Answer: A

Rationale: To convert 0494 to L, we first convert it to inches: 494 cm � 54 cm/in = 9.148 in. Then, we convert inches to L: 9.148 in � 1 L/54 in = 0.169 L. The correct answer is A: 1.40 101 L, which is the correct conversion of 0.169 L to scientific notation. Choices B, C, and D are incorrect due to incorrect conversions or not being in scientific notation.