Which of the following methods would best separate sand and water? boiling filtering decanting distilling

Filtration can be used to separate sand and water.

Explanation:

Insoluble solids can be separated from liquid through filtration. Sand is "insoluble in water". So it can separated through filtration. When sand is mixed with water it either floats or sinks down in the container. Now we can use filter paper or any filtering materials to separate sand from water. The mixture of water and sand can be poured through the filtering material.The filtering material allow all liquid to pass through the pores in it and sand remains behind in the filter paper.

The atomic mass of a carbon isotope that has 6 protons and 7 neutrons is 13

Explanation:

Remember that whilst the atomic number represents the number of protons in an atom, the mass number represents the summation of protons and neutrons particles in the atomic nuclei. Therefore, in this case, the carbon will have a mass number of;

6 +  7 = 13

Isotopes of an element usually have the same atomic number but different mass numbers -because they have slightly different numbers of neutrons. An example is isotopes of Carbon; C-14 and C-12