The wrong answers for sure are B and D, I assume the answer is C
Answer:
669.48 kJ
Explanation:
According to the question, we are required to determine the heat change involved.
We know that, heat change is given by the formula;
Heat change = Mass × change in temperature × Specific heat
In this case;
Change in temperature = Final temp - initial temp
= 99.7°C - 20°C
= 79.7° C
Mass of water is 2000 g ( 2000 mL × 1 g/mL)
Specific heat of water is 4.2 J/g°C
Therefore;
Heat change = 2000 g × 79.7 °C × 4.2 J/g°C
= 669,480 joules
But, 1 kJ = 1000 J
Therefore, heat change is 669.48 kJ
Answer:
D. They have the same number of protons as electrons.
Explanation:
Protons are found in the nucleus of the atom and have a positive charge while electrons orbit around the nucleus and have a negative charge. Usually, in a neutral atom of an element, the number of protons is equal to the number of electrons. This is why the atom has no charge because the positive and negative charges cancel out. When an atom loses an electron its charge turns positive while when it gains an electron its charge turns negative.
