Answer:
Both <u>elements </u>and <u>compounds</u> can be classifies as pure substances because they have distinct properties and composition.
Explanation:
Elements and compounds are considered as pure substances because both are always formed form are have same kind of atoms.
For example,
Carbon dioxide is compound. It always consist of one carbon atom and two oxygen atoms.
Water is compound it always have same kind of atoms two hydrogen and one oxygen that's why compounds are considered as pure substances.
Same is the case with elements. For example,
Hydrogen is element and it always consist of H atoms.
Iron is another element and it always have iron atoms.
So elements and compounds are always consist of same substances that's why they are considered as pure.
The grams of NaCl that are required to make 150.0 ml of a 5.000 M solution is 43.875 g
calculation
Step 1:calculate the number of moles
moles = molarity x volume in L
volume = 150 ml / 1000 = 0.15 L
= 0.15 L x 5.000 M = 0.75 moles
Step 2: calculate mass
mass = moles x molar mass
molar mass of NaCl = 23 + 35.5 = 58.5 mol /L
mass is therefore =0.75 moles x 58.5 mol /l =43.875 g
Molecules may be similar or different on the basis of size, shape, structure and chemical composition.
<h2>Similarities and differences</h2>
Two molecules can be considered similar or different on the basis of size, shape, structure and chemical composition. The molecules in the two proposed systems are consider the same when they are similar in size, shapes, structure and chemical composition.
While on the other hand, the molecules is considered different when they have different structure and chemical composition so we can say that molecules may be similar or different on the basis of size, shape, structure and chemical composition.
Learn more about molecules here: brainly.com/question/26044300
Learn more: brainly.com/question/26268787
Answer:
when silver articles exposed to air silver racts with Sulphur present in the atmosphere and form a black layer of silver sulphide on the surface. copper articles get tarnished by reacting with air and water. due to this, a layer is formed over copper vessels.
A solution that appears dark orange in color is not absorbing all orange wavelengths of light.
