Benefits; helps our red blood cells transport oxygen all around our body
An element is a pure substance that cannot be separated or divided into simpler substances by any method (physical or chemical). The four common elements in all the living organisms are carbon, oxygen, hydrogen, nitrogen.
Thus, the four elements that make up about 96 % of body matter are carbon, oxygen, hydrogen, nitrogen (c).
<u>Answer:</u> The volume of given amount of ethanol at this temperature is 159.44 mL
<u>Explanation:</u>
Specific gravity is given by the formula:

We are given:
Density of water = 0.997 g/mL
Specific gravity of ethanol = 0.787
Putting values in above equation, we get:

Density is defined as the ratio of mass and volume of a substance.
......(1)
Given values:
Mass of ethanol = 125 g
Density of ethanol = 0.784 g/mL
Putting values in equation 1, we get:

Hence, the volume of given amount of ethanol at this temperature is 159.44 mL
Answer:
13.5 %
Explanation:
First we<u> calculate the mass of 500 mL of water</u>, using <em>its density</em>:
- 500 mL * 1.00 g/mL = 500 g
Then we <u>calculate the mass percent of potassium sulfate</u>, using the formula:
Mass of Potassium Sulfate / Total Mass * 100%
- 78 g / (78 + 500) g * 100 % = 13.5 %
<span>Molality(m) or molal concentration is a measure
of concentration and it refers to amount of substance in a specified amount of
mass of the solvent. Used unit for molality is mol/kg which is also
sometimes denoted as 1 molal. It is equal to the moles of solute (the substance
being dissolved) divided by the kilograms of solvent (the substance used to
dissolve).</span>
Molarity(M) or molar concentration is also a
measure of concentration and represents the amount of substance per unit volume
of solution(number of moles per litre of solution. Used unit for molarity is
mol/L or M. A solution with a concentration of 1 mol/L is equivalent to 1 molar
(1 M).
Molality is preferred when
the temperature of the solution varies, because it does not depend on
temperature, (neither number of moles of solute nor mass of solvent will be affected
by changes of temperature), while molarity changes as temperature changes(volume
of solution changes as temperature changes).