water
.
The answer depends on what the numbers measure. If they are the masses of equal volumes of substances, then the substance with mass 0.8 is denser. On the other hand, if the numbers refer to the volumes of equal masses of two substances, then the substance with volume 0.7 is denser.
A spoon is a measure of volume. Different substances have different densities so that the same volume of two substances can have very different masses.
A balance.See the Related Questions to the left for more information.
Different substances have different densities. If you're talking about water, then 1 liter masses 1 kilogram, so 16 liters.
When a single heavy nucleus splits into two or more lighter nuclei (fission), the sum of their masses is less than the mass of the original nucleus. Some mass is missing, and some energy is released. When two light nuclei fuse into a single heavier nucleus (fusion), the mass of the heavier one is less than the sum of the masses of the two light ones. Some mass is missing, and some energy is released. In both events, the missing mass has been converted to energy. If the amount of missing mass is 'm', and you multiply 'm' by the square of the speed of light 'c2' , the answer you get is the amount of energy that was released 'e'. e = mc2
The answer depends on what the numbers measure. If they are the masses of equal volumes of substances, then the substance with mass 0.8 is denser. On the other hand, if the numbers refer to the volumes of equal masses of two substances, then the substance with volume 0.7 is denser.
substances
No, not unless they are made of the same substance. Different substances have different densities, which means that the same volumes will have different masses.
The question isn't worded very well, so I'm not sure this is the answer to what you were trying to ask. The bulk mass of a substance has no impact whatsoever on the melting point of that substance. Covalently bonded molecules with higher molecular masses tend to have higher melting points, if the substances are roughly the "same kind of substance", which is an ill-defined term so you shouldn't put too much faith in this until you've studied chemistry enough to have developed a sort of intuition about what it means.
yes
substances
substances
isotopes
Yes
This question cannot be answered. ppm is a ratio: so many parts of one substance per million parts of another. That can only be converted into mcg if the relative masses of the two substances are known.
Comparing density
The total mass of products is unchanged from the total mass of the reactants, but the masses of particular substances among the reactants or products change.