Answer:
b. The number of electrons
Explanation:
A "neutral atom" has a <u>neutral charge</u>. This means that <em>its charge is equal to </em><em>zero. </em>In order for the charges to cancel out each other, the atom's <em>positive charge should be equal to the negative charge. </em>These being said, the number of electrons<em> (negatively-charged)</em> is then equal to the number of protons <em>(positively-charged). </em>Those atoms which are not neutral are called <em>"ions."</em> This means that they either have more or less electrons than the protons.
<span>1. Blocks Ultra violet rays that can be harmful.
2. Provides Oxygen, so we can live.
3. It blocks meteors from hitting Earth's surface.
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Answer: fourth option, 10.8 kJ
Explanation:
The <em>heat of fusion</em>, also named latent heat of fusion, is the amount of heat energy required to change the state of a substance from solid to liquid (at constant pressure).
The data of the <em>heat of fusions</em> of the substances are reported in tables and they can be shown either per mole or per gram of substance.
In this case we have that the<em> heat of fusion for water </em>is reported per mole: <em>6.02 kJ/mole</em>.
The formula to calculate <em>how many kJ of heat (total heat) are needed to completely melt 32.3 g of water, given that the water is at its melting point</em> is:
- Heat = number of moles × heat of fusion
The calculations are:
- number of moles = mass / molar mass
number of moles = 32.3 g / 18.015 g/mol = 1.79 mol
- Heat = 1.79 mol × 6.02 kJ / mol = 10.8 kJ ← answer
I think it’s the third option but I’m not entirely sure
