Nursing Elites

1. In a balanced chemical equation, the coefficients represent the:

• A. Number of elements
• B. Ratio of reactants and products
• C. Physical state of the substances
• D. Rate of the reaction

Correct answer: A

Rationale: The correct answer is A: 'Number of elements.' In a balanced chemical equation, coefficients represent the ratio of moles of each species involved in the reaction. They indicate the relative number of molecules or formula units of each compound taking part in the reaction. Choice B, 'Ratio of reactants and products,' is incorrect because the coefficients in a balanced equation do not represent the ratio of reactants and products directly, but rather the stoichiometry of the reaction. Choice C, 'Physical state of the substances,' is incorrect because the physical states (solid, liquid, gas, or aqueous) are denoted with symbols next to the chemical formula, not the coefficients. Choice D, 'Rate of the reaction,' is incorrect as coefficients in a balanced equation do not provide information about the rate of the reaction, which is determined by factors like temperature, concentration, and catalysts.

2. Convert 1.25 kilograms to grams.

• A. 12.5 grams
• B. 125 grams
• C. 1,250 grams
• D. 1250 mg

Correct answer: C

Rationale: To convert kilograms to grams, you need to multiply by 1000 since there are 1000 grams in a kilogram. Therefore, 1.25 kilograms is equal to 1.25 x 1000 = 1,250 grams. Choices A, B, and D are incorrect because they do not correctly convert kilograms to grams.

3. Which of the following is NOT a type of chemical bond?

• A. Ionic bond
• B. Covalent bond
• C. Metallic bond
• D. Gravitational bond

Correct answer: D

Rationale: Ionic, covalent, and metallic bonds are all types of chemical bonds that involve the sharing or transfer of electrons between atoms. An ionic bond occurs when one atom donates an electron to another, creating positive and negative ions that attract each other. A covalent bond involves the sharing of electrons between atoms to achieve a stable electron configuration. Metallic bonds are formed between metal atoms where electrons are delocalized and move freely among the metal ions. On the other hand, a gravitational bond is not a type of chemical bond. It refers to the force of attraction between two objects with mass, such as the gravitational force between the Earth and objects on its surface. Therefore, the correct answer is 'Gravitational bond.'

4. What does half-life refer to?

• A. Radioactive intensity to completely disappear
• B. The number of neutrons in a nucleus to double
• C. The number of protons in a nucleus to change
• D. An isotope to decay by half of its initial quantity

Correct answer: D

Rationale: Half-life refers to the time it takes for half of the radioactive atoms in a sample to decay. This means that after one half-life, half of the initial quantity of the radioactive substance will have decayed. Choice A is incorrect because radioactive intensity doesn't completely disappear during half-life. Choice B is incorrect as half-life doesn't refer to the number of neutrons doubling. Choice C is incorrect as half-life doesn't relate to the number of protons changing.

5. What is the equivalent of 0.3 mg in ml?

• A. 0.3 ml
• B. 3 ml
• C. 30 ml
• D. 0.03 ml

Correct answer: A

Rationale: The correct answer is A: 0.3 ml. To convert milligrams (mg) to milliliters (ml), you typically need the substance's density. However, in many medical contexts, especially with liquid medications similar in density to water, 0.3 mg is commonly assumed to be equivalent to 0.3 ml. Choice B (3 ml) is incorrect as it is 10 times greater than the correct conversion. Choice C (30 ml) is incorrect as it is 100 times greater than the correct conversion. Choice D (0.03 ml) is incorrect as it is one-tenth of the correct conversion.

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