The correct answer is an ionic bond
pOH =
pH =
[H+] =
Answer: pOH= 4.06
pH= 9.94
Explanation: pOH is the negative logarithm of concentration.
pH is the negative logarithm of concentration.
2)
3)
(2) 35.0% (4) 60.0%
Answer:
The correct option is (2) 35.0%
Explanation:
If we want to calculate the percent composition by mass of nitrogen in NH4NO3 we first need to calculate the mass of nitrogen in one mole of NH4NO3.
Because of the molecular form of NH4NO3 (it has 2 ''N'') we know that one mole of NH4NO3 contains 2 moles of N.
The molar mass of N (nitrogen) is
This means that 1 mole of N contains 14.0067 grams of N.
Because we have 2 moles of N ⇒
We know that in 1 mole of NH4NO3 we have 2 moles of N(28.0134 g of N).
To calculate the percent composition by mass of nitrogen we need to divide the mass of nitrogen in one mole of NH4NO3 by the mass of one mole of NH4NO3 and then multiply it by 100.
We know that in 1 mole of NH4NO3 there are 80.0 g of NH4NO3 (Because of the molar mass data) ⇒
% ≅ 35.0%
We find that the percent composition by mass of nitrogen in NH4NO3 is 35.0%
We conclude that the correct option is (2) 35.0%
Answer:
1.60 is the van't Hoff factor for ammonium chloride in X.
Explanation:
...(1)
where,
=Elevation in boiling point =
i = van't Hoff factor
= Freezing point constant
m = molality
1) When 70.4 g of benzamide are dissolved in 850. g of a certain mystery liquid X.
Mass of benzamide = 70.4 g
Molar mass of benzamide = 121 g/mol
i = 1 (organic molecule)
Mass of liquid X = 850 g = 0.850 kg
= Freezing point constant of liquid X= ?
Putting all value in a (1):
2) When 70.4 g of ammonium chloride are dissolved in 850. g of a certain mystery liquid X.
Mass of ammonium chloride= 70.4 g
Molar mass of ammonium chloride = 53.5 g/mol
i = ? (ionic molecule)
Mass of liquid X = 850 g = 0.850 kg
Putting all value in a (1):
i = 1.6011 ≈ 1.60
1.60 is the van't Hoff factor for ammonium chloride in X.
The van't Hoff factor, which measures ionization, for ammonium chloride in the mysterious liquid X can be calculated to be approximately 1.01. This is calculated by first determining the cryoscopic constant from the observed depression of the freezing point by benzamide (which does not ionize), and then utilizing this value to calculate the theoretical freezing point depression for ammonium chloride (pretending it does not ionize either). Since the observed depression was 9.9℃ and the calculated was 9.8℃, the van't Hoff factor is their quotient, or approximately 1.01.
To solve this problem, we need to understand that the van't Hoff factor (i) is a measure of the extent of ionization in solution. It can be calculated using the formula i = ΔTf observed / ΔTf calculated, where ΔTf observed is the observed freezing point depression and ΔTf calculated is the theoretical freezing point depression if no ionization occurs.
First, we calculate the theoretical freezing point depression for ammonium chloride. We know that this is given by the benzamide that reduces the freezing point of the same amount of liquid X by 2.7℃. Therefore we assume the van't Hoff factor of benzamide is 1 (since it does not ionize) and we get the cryoscopic constant (Kf) of X from ΔTf = Kf * m * i. Substituting into the formula and rearranging gives Kf = ΔTf / (m * i) = 2.7 ℃/(70.4 g/850 g) = 2.7 ℃/0.082824 = 32.6 ℃ kg/mol.
We then use this Kf to calculate the ΔTf calculated for ammonium chloride: ΔTf calculated = Kf * m * i (where we again assume i=1) = 32.6 ℃ kg/mol * (70.4 g/850 g) = 9.8 ℃. Finally we can calculate the van't Hoff factor for ammonium chloride using the original formula: i = ΔTf observed / ΔTf calculated = 9.9 ℃ / 9.8 ℃ = 1.01.
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B. Soda mixed with the pizza sauce and sped up digestive enzyme activity.
C. Soda raised the pH in his stomach and sped up digestive enzyme activity.
D. Soda lowered the pH in his stomach and slowed digestive enzyme activity.
2. Which factor decreases the rate of a chemical reaction?
A. An inhibitor
B. A co-factor
C. Increased substrate
D. Cold temperature
3. Which component decreases the activation energy of a chemical reaction?
A. An inhibitor solution
B. Presence of an enzyme
C. Lower substrate concentration
D. Neutral pH levels
4. A biologist adds a vitamin solution to an enzyme/substrate solution that requires co-factors. What will happen to the substrate?
A. The vitamins will bond to the enzymes and increase their reactivity with the substrates.
B. The vitamins will bond to the enzymes and decrease their reactivity with the substrates.
C. The substrate molecules will bond to the vitamin molecules and inhibit bonding of the enzyme.
D. The substrate molecules will bond to the vitamin molecules and stimulate bonding of the enzyme.
5. Jennifer stews peaches to make peach jelly. She believes the homemade jelly will make a healthy treat full of vitamins and enzymes her body needs. Which of the following disproves her prediction?
A. The peaches don't contain enzymes.
B. The jelly has too much sugar to be healthy.
C. The enzymes in the peaches have denatured.
D. The vitamins in the peaches will inhibit the enzymes.
6. What statement best describes what happens during the catalytic cycle?
A. The enzyme breaks the substrate apart to prepare for the reaction.
B. The enzyme positions the substrate to increase access during a reaction.
C. The substrate uses enzyme energy to start the reaction.
D. The active site releases the substrate and replaces it with an inhibitor.
Answer 1) Option D) Soda lowered the pH in his stomach and slowed digestive enzyme activity.
Explanation : Consuming soda after eating pizza lowered the pH of the stomach which consequently, slowed the digestive enzyme activity in the stomach. The enzymes actively digest the food only in highly acidic environment.
Answer 2) Option A) An inhibitor
Explanation : An inhibitor is a substance usually added to a progressing chemical reaction to decrease the rate of reaction and finally stop the reaction.
Answer 3) Option B) Presence of an enzyme
Explanation : When an enzyme is added to a chemical reaction it is often seen that it lowers the energy of activation and catalyzes the reaction. So, enzyme acts as a catalyst and increases the reaction rate.
Answer 4) Option A) The vitamins will bond to the enzymes and increase their reactivity with the substrates.
Explanation : When the biologists adds a vitamin solution to an enzyme or a substrate solution the bonding will take place between vitamins and enzymes and as a result it will increase the reactivity of the substrates.
Answer 5) Option C) The enzymes in the peaches have denatured.
Explanation : When enzymes are stewed or rather boiled they become denatured and the bonds between them breaks, which makes the enzyme useless. Hence, proteins should be eaten raw without boiling at higher temperatures.
Answer 6) Option A) The enzyme breaks the substrate apart to prepare for the reaction.
Explanation : In a catalytic reaction the enzymes usually break the substrate and create more surface area for the reaction to occur.
FALSE