Answer:
1. An apple is something that has matter.
2. Light does not have matter. It neither has mass or takes up and space.
3. Physical changes only change the appearance of a substance, not its chemical composition. Chemical changes cause a substance to change into an entirely substance with a new chemical formula. Chemical changes are also known as chemical reactions.
4. A chemical reaction is usually accompanied by easily observed physical effects, such as the emission of heat and light, the formation of a precipitate, the evolution of gas, or a color change. Absolute confirmation of a chemical change can only be validated by chemical analysis of the products!
5. A precipitate is a solid that forms out of solution.
6. In simple terms, the endothermic reactions absorb energy from the surrounding that is in the form of heat. On the other hand, an exothermic reaction releases energy into the surrounding of the system.
Explanation:
Matter is anything that has mass and takes up volume.
Answer: D) More moles of ions are present in a given volume of 0.10 M 
than in the same volume of 0.10 M NaCl.
Explanation:
A electrolyte is a solution that dissociates completely when dissolved in water. The ions act as good conductors of electric current in the solution.
More is the number of ions , more will be the conductance and hence the solution will be a better conductor of electricity.
0.10 M aqueous solution of is a better conductor of electricity as it dissociates to give three ions whereas 0.10 M aqueous solution of 
dissociates to give two ions only.
Thus 0.10 M aqueous solution of sodium sulfate, , is a better conductor of electricity as more moles of ions are present in a given volume of 0.10 M than in the same volume of 0.10 M
The molecule that contains the fewest number of Hydrogen atoms would be B. Al(OH)3. It only has 3 Hydrogen atoms.
Answer:
6.564×10¹⁶ fg.
Explanation:
The following data were obtained from the question:
Mass of beaker = 76.9 g
Mass of beaker + salt = 142.54 g
Mass of salt in fg =?
Next, we shall determine the mass of the salt in grams (g). This can be obtained as follow:
Mass of beaker = 76.9 g
Mass of beaker + salt = 142.54 g
Mass of salt =?
Mass of salt = (Mass of beaker + salt) – (Mass of beaker)
Mass of salt = 142.54 – 76.9
Mass of salt = 65.64 g
Finally, we shall convert 65.64 g to femtograms (fg) as illustrated below:
Recall:
1 g = 1×10¹⁵ fg
Therefore,
65.64 g = 65.64 g × 1×10¹⁵ fg / 1g
65.64 g = 6.564×10¹⁶ fg
Therefore, the mass of the salt is 6.564×10¹⁶ fg.
