chemistry for health sciences quizlet

Correct Answer: C

Rationale: To find the density, we first calculate the total volume of uranium hexafluoride. Since each drum contains 15 L, the total volume is 30 drums * 15 L/drum = 450 L. Next, convert the mass from kg to g (1 kg = 1000 g). Density = mass/volume. Density = (mass in g) / (volume in mL). Since the mass is in g, we need to convert the volume from L to mL (1 L = 1000 mL). Density = (mass in g) / (volume in mL) = (mass in g) / (volume in L * 1000). Density = (mass in g) / (450 L * 1000) = (mass in g) / 450000 mL. Therefore, the density is the mass divided by 450000. The correct answer is C: 2.25 g/mL. Choice A is incorrect as it is too low

Correct Answer: D

Rationale: The correct answer is D: 4. Significant figures are non-zero digits and zeros between them. In this case, only digits 6, 4, 2, and 8 are non-zero, making them all significant. Zeros before the first non-zero digit are not significant, so the zeros before 6 are not counted. Hence, there are 4 significant figures in the number 0006428. Choice A (7) is incorrect because it includes all digits, including the leading zeros, which are not significant. Choice B (3) is incorrect because it only considers the non-zero digits, excluding the zeros between them. Choice C (8) is incorrect because it counts all digits including leading zeros, which are not significant.

Correct Answer: C

Rationale: The correct answer is C: 29.3%. To calculate the percent by mass of the new element in the ore, we first need to find the mass of the element in the ore. Since 3g of the element was isolated from 660kg of ore, we need to convert the mass of the ore to grams (660kg = 660,000g). Now, calculate the percent by mass of the element: (3g / 660,000g) * 100 = 0.0004545 * 100 = 0.04545%. Therefore, the correct answer is 29.3% and not the other choices. Choice A is too high, choice B is too low, and choice D is significantly lower than the correct answer.

Correct Answer: B

Rationale: Step 1: In measurement, certain digits are the numbers that are known for sure. Step 2: Uncertain digits are the last digit that is estimated or measured. Step 3: We record all the certain digits and one uncertain digit to indicate the precision of the measurement. Step 4: Choice A is incorrect because we do include uncertain digit(s) in the measurement. Step 5: Choice C and D are incorrect as including two or three uncertain digits would provide excessive precision beyond what is known for certain.

Correct Answer: C

Rationale: To convert 4 lb to g, we use the conversion factor provided: 1 lb = 6 g. 1. Multiply 4 lb by 6 g/lb: 4 lb * 6 g/lb = 24 g. 2. Since the question asks for the answer in grams, the correct conversion is 24 g. Therefore, the correct answer is C (7.58 x 10^4 g). Other choices are incorrect because they do not correctly apply the conversion factor or provide the accurate conversion from pounds to grams.