What is the density of a wood that has a mass of 40.0 grams and a volume of 15.0 cm3?

Explanation:

Density can be found by dividing the mass by the volume.

The mass of the wood is 40.0 grams and the volume is 15.0 cubic centimeters.

Substitute the values into the formula.

Divide.

As a decimal the density is:

This can be rounded to the nearest hundredth. The 6 in the thousandth place tells us to round the 6 to a 7.

The density of the wood is about 2.67 grams per cubic centimeters.

i'm assuming that the correct answer is indeed the first one/ "a"..

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.