B) energy is absorbed by the reaction
is right answer.
Scientists developed symbols and gave the elements numbers to help organize the elements by their chemical properties. The periodic table helps identify the underlying chemical and physical traits of the elements.
Answer:
H2 > N2 > Ar > CO2
Explanation:
Graham's law explains why some gases efuse faster than others. This is due to the difference i their molar mass. Generally; The rate of effusion of gaseous substances is inversely proportional to the square rot of its molar mass.
This means gases with low molar masses would have higher efusion rate compared to gases with higher molar masses.
So now we just need to compare the molar masses of the various gases;
Ar - 39.95
CO2 - 44.01
H2 - 2
N2 - 28.01
To obtain the order in increasing rate, we have to order the gases in decreasing molar mass. This order of increasing rate is given as;
H2 > N2 > Ar > CO2
What's the problem ? Hardness is not the definition of a metal.
You need to expand your thinking. EVERY element is solid, liquid, and gas, over different ranges of temperature ... including all of the metals. There are only TWO elements that are liquid AT ROOM TEMPERATURE, and mercury is one of them. But on a mild day at the south pole, mercury is solid too.
