Nokea
An element has 6 protons, 6 electrons, and 6 neutrons. What is its atomic number?
- A. 6
- B. 12
- C. 18
- D. Not enough information
Correct Answer: A
Rationale: The atomic number of an element is determined by the number of protons in its nucleus. Since the element in question has 6 protons, its atomic number is also 6. The number of neutrons and electrons does not impact the atomic number, which is solely based on the number of protons. Therefore, the correct answer is A: 6.
You may also like to solve these questions
What does carbonic acid become within the human body?
- A. Digests food
- B. Kills viruses
- C. Maintains pH of blood
- D. Grows hair
Correct Answer: C
Rationale: Carbonic acid, formed when carbon dioxide dissolves in water, plays a crucial role in maintaining the pH balance of the blood. It acts as a buffer to prevent drastic changes in blood pH, which is vital for the body's proper functioning. Carbonic acid does not digest food, kill viruses, or contribute to hair growth. Therefore, options A, B, and D are incorrect roles of carbonic acid within the human body, making maintaining the pH of blood (Option C) the correct answer.
How many water molecules are present in the products?
- A. 2
- B. 4
- C. 1
Correct Answer: A
Rationale: In chemical reactions, it is essential to balance the equation to determine the quantity of each molecule present in the products accurately. For this specific reaction, the balanced equation reveals that 2 water molecules are produced. When the reactants undergo the reaction, the products formed include 2 water molecules. Thus, the correct answer is A: 2.
What is the density of iron when 28.5g of iron shot is added to a graduated cylinder containing 45.5mL of water, causing the water level to rise to the 49.1mL mark?
- A. 0.63 g/mL
- B. 7.92 g/mL
- C. 0.58 g/mL
- D. None of the above
Correct Answer: B
Rationale: To determine the density of iron, we use the formula: Density = Mass / Volume. The mass of the iron is given as 28.5g. The volume of water displaced by the iron is the final volume (49.1mL) minus the initial volume (45.5mL), resulting in 3.6mL. Therefore, the density of iron can be calculated by dividing the mass of iron (28.5g) by the volume of water displaced (3.6mL), giving us 7.92 g/mL. Therefore, choice B, 7.92 g/mL, is the correct answer.
What role does carbonic acid play in the human body?
- A. Digests food
- B. Kills viruses
- C. Maintains pH of blood
- D. Grows hair
Correct Answer: C
Rationale: In the human body, carbonic acid, formed when carbon dioxide dissolves in water, plays a crucial role in maintaining the pH balance of blood. It acts as a buffer system, responsible for regulating blood acidity levels and preventing significant pH fluctuations that could harm the body. Choices A, B, and D are inaccurate as they do not reflect the actual function of carbonic acid in the human body.
What is 119°K in degrees Celsius?
- A. 32°C
- B. -154°C
- C. 154°C
- D. -32°C
Correct Answer: B
Rationale: The correct answer is 'B: -154°C.' To convert Kelvin to Celsius, you subtract 273.15 from the temperature in Kelvin. For 119°K: 119 - 273.15 = -154.15. Thus, 119°K is equal to approximately -154°C.