Give four different chemical meanings for the word element and an example of each

Answer ;

-An element is a substance containing only one type of atom, for example; H2 or 02  (consisting of atoms that all have the same number of protons).

-Microscopic, single atom of that element

-Macroscopic, sample of that element large enough to weigh on a balance

- A substance that cannot be broken down chemically; e.g; sodium metal,

Explanation;

-An element is a substance whose atoms all have the same number of protons: another way of saying this is that all of a particular element's atoms have the same atomic number. Elements are chemically the simplest substances and hence cannot be broken down using chemical reactions.

-An element is uniquely determined by the number of protons in the nuclei of its atoms.

1 a

2 d

3 a

4 c

explanation:

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%