ATI TEAS 7
Science TEAS Practice Test
1. How many grams of solid CaCO3 are needed to make 600 mL of a 0.35 M solution? The atomic masses for the elements are as follows: Ca = 40.07 g/mol; C = 12.01 g/mol; O = 15.99 g/mol.
- A. 18.3 g
- B. 19.7 g
- C. 21.0 g
- D. 24.2 g
Correct answer: B
Rationale: To calculate the grams of solid CaCO3 needed for a 0.35 M solution, we first find the molar mass of CaCO3: Ca = 40.07 g/mol, C = 12.01 g/mol, O = 15.99 g/mol. The molar mass of CaCO3 is 40.07 + 12.01 + (3 * 15.99) = 100.08 g/mol. The molarity formula is Molarity (M) = moles of solute / liters of solution. Since we have 0.35 moles/L and 600 mL = 0.6 L, we have 0.35 mol/L * 0.6 L = 0.21 moles of CaCO3 needed. Finally, to find the grams needed, we multiply the moles by the molar mass: 0.21 moles * 100.08 g/mol = 21.01 g, which rounds to 19.7 g. Therefore, 19.7 grams of solid CaCO3 are needed to make 600 mL of a 0.35 M solution. Choice A (18.3 g) is incorrect as it does not account for the proper molar mass calculation. Choice C (21.0 g) and Choice D (24.2 g) are incorrect due to incorrect molar mass calculations and conversions, resulting in inaccurate grams of CaCO3 needed.
2. If an organism is AB, which of the following combinations in the gametes is NOT possible?
- A. AB
- B. AA
- C. BB
- D. AB
Correct answer: B
Rationale: The correct answer is B. If an organism is AB, it indicates that it carries two different alleles. During gamete formation, each gamete receives only one allele from the pair present in the organism. Therefore, in this case, the possible gametes would be 'A' and 'B,' making 'AA' impossible. Choice A, 'AB,' is possible as each gamete can carry one of the alleles from the genotype. Similarly, 'BB' is also possible if one of the alleles separates into a gamete. Choice D, 'AB,' is essentially the same genotype as the organism and is a possible combination in the gametes.
3. In order to be included in the formation of a scientific conclusion, evidence must be:
- A. Quantitative
- B. Reproducible
- C. Obvious
- D. All of the above
Correct answer: B
Rationale: For scientific evidence to be included in the formation of a scientific conclusion, it must be reproducible. Reproducibility is a fundamental aspect of the scientific method, ensuring that the same experiment will yield the same results if repeated. This allows other researchers to verify the findings and conclusions drawn from the evidence, enhancing the reliability and validity of the scientific process. While quantitative data can be important in supporting evidence, it is not a strict requirement for evidence to be included in scientific conclusions. The term 'obvious' is subjective and does not necessarily guarantee the reliability or reproducibility of the evidence, making it an unreliable criterion for scientific conclusions. Therefore, choice B, reproducible, is the correct answer as it aligns with the fundamental principles of the scientific method, emphasizing the importance of replicating results for establishing reliable conclusions.
4. Which of the following nucleobases does not exist in RNA?
- A. Uracil
- B. Thymine
- C. Cytosine
- D. Guanine
Correct answer: B
Rationale: The correct answer is 'B: Thymine'. Thymine is a nucleobase found in DNA but is replaced by uracil in RNA. RNA contains Uracil, Cytosine, and Guanine as its nucleobases. Cytosine and Guanine are present in both DNA and RNA, while Thymine is exclusive to DNA and Uracil is specific to RNA.
5. Which structure serves as the electrical stimulator of the cardiac muscle?
- A. The sinoatrial node
- B. The left ventricle
- C. The aorta
- D. The tricuspid valve
Correct answer: A
Rationale: The correct answer is the sinoatrial node. This node, also referred to as the pacemaker of the heart, is responsible for initiating the electrical impulses that stimulate cardiac muscle contractions. It plays a crucial role in setting the pace and rhythm of the heart's contractions. Choices B, C, and D (the left ventricle, the aorta, and the tricuspid valve, respectively) do not serve as the primary electrical stimulator of the cardiac muscle. While the left ventricle is a chamber of the heart that pumps oxygenated blood to the body, the aorta is the main artery that carries blood away from the heart, and the tricuspid valve is a one-way valve that ensures blood flows properly through the heart, none of these structures initiate the electrical impulses that cause the cardiac muscle to contract.
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