Answer: The student’s percent error is 3.16%.
Explanation:
Calculated mass of the block = 16.3 g
Actual mass of the block = 15.8 g


The student’s percent error is 3.16%.
Which elements are most reactive?
The alkali metals, found in group 1 of the periodic table (formerly known as group IA), are very reactive metals that do not occur freely in nature. These metals have only one electron in their outer shell. Therefore, they are ready to lose that one electron in ionic bonding with other elements.
Fluorine is the most reactive
Regretfully, I do not know what is asked of the problem because it is not stated above. However, it is easier to answer any question pertaining to the temperature, volume, and pressure of gases by assuming that they behave ideally. With this, we'll be able to use the ideal gas law which is mathematically expressed as,
PV = nRT
where P and V are pressure and volume, respectively. n is the amount of material in mol, R is gas constant, and T is temperature.
Answer: 55.56 moles of MgO
Explanation:
1 mole = avogadro number
if 6.21x10^25 atoms then molecules of MgO (equal numbers of Mg and O atoms)
= 0.5*6.21x10^25 = 3.105 molecules of MgO
So moles of MgO = 0.5*6.21*10^25/avogadro number = 55.56