Answer:
Option-C (27.36% Na, 1.20% H, 14.30% C, and 57.14% O)
Explanation:
<em>Percent Composition</em> is defined as the <u><em>%age by mass of each element present in a compound</em></u>. Therefore, it is a relative amount of each element present in a compound.
Calculating Percent Composition of NaHCO₃:
1: Calculating Molar Masses of all elements present in NaHCO₃:
a) Na = 22.99 g/mol
b) H = 1.01 g/mol
c) C = 12.01 g/mol
d) O₃ = 16.0 × 3 = 48 g/mol
2: Calculating Molecular Mass of NaHCO₃:
Na = 22.99 g/mol
H = 1.01 g/mol
C = 12.01 g/mol
O₃ = 48 g/mol
----------------------------------
Total 84.01 g/mol
3: Divide each element's molar mass by molar mass of NaHCO₃ and multiply it by 100:
For Na:
= 22.99 g.mol⁻¹ ÷ 84.01 g.mol⁻¹ × 100
= 27.36 %
For H:
= 1.01 g.mol⁻¹ ÷ 84.01 g.mol⁻¹ × 100
= 1.20 %
For C:
= 12.01 g.mol⁻¹ ÷ 84.01 g.mol⁻¹ × 100
= 14.29 % ≈ 14.30 %
For O:
= 48.0 g.mol⁻¹ ÷ 84.01 g.mol⁻¹ × 100
= 57.13 % ≈ 57.14 %
<u>Answer:</u> The correct answer is Option d.
<u>Explanation:</u>
We are given:
Mass percentage of 
= 20 %
So, mole fraction of = 0.2
Mass percentage of 
= 30 %
So, mole fraction of = 0.3
Mass percentage of 
= 35 %
So, mole fraction of = 0.35
Mass percentage of 
= 15 %
So, mole fraction of = 0.15
We know that:
Molar mass of = 16 g/mol
Molar mass of = 28 g/mol
Molar mass of = 26 g/mol
Molar mass of = 48 g/mol
To calculate the average molecular mass of the mixture, we use the equation:
where,
= mole fractions of i-th species
= molar masses of i-th species
= number of observations
Putting values in above equation:
Hence, the correct answer is Option d.
It's called simple diffusion, the small molecules without charges such as oxygen and carbon dioxide can flow through a plasma membrane without assistance and without expending energy. Other substances such as proteins, glucose and charged particles called ions cannot pass through the selectively permeable membrane.
Answer:
Carbon
Explanation:
Carbon has four electrons in its valence shell, so it generally shares it in a covalent bond. This element needs four electrons to be stable, so it can form single (such as the bond with hydrogen), double (such as the bond with oxygen) or triple bonds (such as the bond with nitrogen).
It can also form bonds with other carbon, and they can form longs chains, that's why there are a lot of organic compounds (the compounds with carbon). Carbon can form rings too, such as in benzene.
Answer:
- <u>1. Since the temperature of your body is higher than the temperature of the air and of the water, heat will flow from your body to the air and pool.</u>
<u></u>
- <u>2. The pool feels cooler than air because the water can absorb heat energy faster than the air, due to liquids are better conductors than gases.</u>
<u></u>
Explanation:
Heat always flows from warmer substances to colder ones.
The normal body temperature is 98ºF. Therefore, the heat will flow from your body to the air and pool, which are at a lower temperature of 80ºF. In both cases, you will lose thermal energy and the external parts of your body will cool down.
The difference between both cases is in the heat conduction capacity of both air and water.
Liquids (and solids) are better <em>thermal conductors </em>than gases because the conduction of heat occurs as result of the direct contact between the particles of matter: the atoms or molecules in hot matter vibrate faster than their neighbors and transmit them kinetic energy by direct contact.
Therefore, the liquid water in the swimming pool, at the same temperature than the air, will be able to absorb more heat in the same time from the body.
In conclusion, the body will cool down faster in water than in air which is why the pool feels cooler than air.
