I'm not 100% sure but I'm leaning towards D. :)
4% mass / volume :
4 g ---------> 100 mL
1.2 g ------- ? mL
V = 1.2 * 100 / 4
V = 120 / 4
V = 30 mL
hope this helps!
If the units for gases were the same as the units for numbers would be too small to be convenient.
For example, the density of iron is 7.87 g/cm³.
Using the same units, the density of hydrogen is 0.000 0899 g/cm³.
It is much more convenient to express the density in numbers that are easier to visualize: 0.0899 g/L, and that is still a small number.
Strong acids have a higher PH while weaker acids have a lower PH
I'm other words, acidic bases have a higher PH whilst less acidic bases have lower PH
