What do methanol (CH2O), ethanoic acid (C2H4O2), and glucose (C3H6O3) all have in common?
1 answer:
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The question is incomplete, here is a complete question.
Which aqueous solution would have the lowest vapor pressure at 25°c.
A) 1 M NaCl
B) 1 M
C) 1 M
D) 1 M
E) 1 M
Answer : The correct option is, (B) 1 M
Explanation :
According to the relative lowering of vapor pressure, the vapor pressure of a component at a given temperature is equal to the mole fraction of that component of the solution multiplied by the vapor pressure of that component in the pure state.
1 M means that the 1 moles of solute present in 1 liter of solution.
Formula used :
where,
= vapor pressure of the pure component (water)
= vapor pressure of the solution
= mole fraction of solute
i = Van't Hoff factor
As we know that the vapor pressure depends on the mole fraction of solute and the Van't Hoff factor.
So, the greater the number of particles of solute dissolved the lower the resultant vapor pressure.
(a) The dissociation of 1.0 M will be,
So, Van't Hoff factor = Number of solute particles = = 1 + 1 = 2
(b) The dissociation of 1 M will be,
So, Van't Hoff factor = Number of solute particles = = 3 + 1 = 4
(c) The dissociation of 1 M is not possible because it is a non-electrolyte solute. So, the Van't Hoff factor will be, 1.
(d) The dissociation of 1.0 M will be,
So, Van't Hoff factor = Number of solute particles = = 1 + 2 = 3
(e) The dissociation of 1 M is not possible because it is a non-electrolyte solute. So, the Van't Hoff factor will be, 1.
From this we conclude that, 1 M has the highest Van't Hoff factor which means that the solution will exhibit the lowest vapor pressure.
Hence, the correct option is, (B) 1 M
Answer:
Molecular mass of β‑galactosidase = 1.16*10^5g
Explanation:
The osmotic pressure (π) is related to the molarity (M) of a solution by the following equation:
i = Von't hoff factor = 1 for non-electrolytes
R = gas constant = 0.0821Latm/mol-K
T = temperature
Based on the above equation, molarity of β‑galactosidase is:
Answer
D. Acid rain reacting with limestone bedrock.
Explanation:
- Brief Description:
- A chemical reaction occurs when acidic rainfall falls on limestone or chalk. During the process, new, soluble compounds are produced. These disintegrate in the sea and are washed away, weathering the rock. Some forms of rock are resistant to chemical weathering. When rain falls from the sky onto a limestone (CaCO3) statue, a reaction between sulphuric acid and calcium carbonate happens. Calcium sulfate is formed as a result of this process (CaSO4). Because calcium sulfate is soluble in water, the statue will ultimately disintegrate. Limestone is chemically worn through the carbonation process. Rainwater collects carbon dioxide as it travels through the atmosphere, forming a weak carbonic acid. Water and carbon dioxide react to generate a mild carbonic acid. The fractures in the limestone are acted upon by this mild carbonic acid. Many weak acids, such as carbonic acid, are found in water. When carbon dioxide gas from the atmosphere combines with rainfall, a weak but copious acid is created. Other forms of acid rain are produced by sulfur dioxide and nitrogen gases, which function as chemical weathering agents.
- Chemical weathering is generally the most active and effective weathering process. Water within soil or stone dissolves minerals of soil, softens minerals that absorpb the water, and dissolves carbondioxide.
- Chemical weathering is the breakdown of rock by chemical processes. Water, air, and chemicals released by organisms cause chemical weathering of rocks when they dissolve the minerals in a rock.
- Carbon Dioxide-Bicarbonate-Carbonate Equilibrium
- The carbon dioxide/bicarbonate/carbonate buffer is an essential buffer in surface waters. When water is in equilibrium with both CO2 from the atmosphere and carbonate-containing rock, its pH is buffered to 8.3, which is close to the pKa of the weak acid bicarbonate HCO3- (pKa = 8.4).
- The production of nitric and sulfuric acids in our atmosphere causes acid rain. These chemicals are strong acids that are very soluble in water and dissolve in cloud water droplets.
- The majority of nitrogen and sulfur oxides are caused by human activity. Electric utilities (60 percent), industrial combustion (17 percent), and industrial processes are the principal sources of sulfur dioxide emissions (8 percent ). Transportation, with internal combustion engines, accounted for more than half of all NOx emissions, with additional emissions from electric utilities (26 percent) and industrial combustion accounting for the remainder (14 percent ). Agricultural operations, particularly manure management, are the biggest source of ammonia emissions, but industry and transportation also emit some ammonia. Acid rain leads to the acidity of lakes and streams, as well as the degradation of trees at high elevations and vulnerable forest soils.
- Calcium carbonate, often known as [Ca][CO3], is a common mineral. One well-known form of calcium carbonate is limestone. Acids in acid rain increase calcium carbonate breakdown by interacting with the carbonate anion.
- This results in a bicarbonate solution. Because surface waters are in balance with atmospheric carbon dioxide, the concentration of carbonic acid, H2CO3, in the water remains constant.Because the minerals react with the excess acid, the presence of limestone and other calcium carbonate rock in lakes and streams helps to maintain a steady pH. However, acid rain can finally overwhelm the surface water's buffering ability.
