D, 2Cu + O2 → 2CuO. A is wrong because oxygen is a diatomic element, meaning it always has to come in the form of O2 in the case of gas. B is wrong because the equation isn't balanced correctly; there's two oxygens on the reactants side, while only one oxygen on the products side. C is wrong because it's saying you're STARTING OUT with CuO already: that doesn't correspond with the word problem. Thus leaves D, where the equation is balanced correctly, has the diatomic oxygen, and ends with CuO.
Answer:
evaporation and distilation
Explanation:
Answer:
December
Explanation:
Southern Hemisphere experiences winter in July, therefore it experiences Summer in December.
This is an exception to the general electronegativity trend. It can be explained by looking at the electron configurations of both elements.
<span>Be:[He]2<span>s2
</span></span><span>B:[He]2<span>s2</span>2<span>p1
</span></span>
When you remove an electron from beryllium, you are taking away an electron from the 2s orbital. When you remove an electron from boron, you are taking an electron from the 2p orbital. The 2p electrons have more energy than the 2s, so it is easier to remove them as they can more strongly resist the effective nuclear charge of the nucleus.
