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Juli2301 [7.4K]
2 years ago
14

When ammonium nitrate is dissolved in water in a glass container, the glass container becomes cold. Is this an endothermic or ex

othermic reaction? How do you know?
A. It is endothermic; heat energy has been removed from the surroundings, making the container cold.
B. It is endothermic; heat energy has been released to the surroundings, leaving the container cold.
C. It is exothermic; heat energy has been released to the surroundings, leaving the container cold.
D. It is exothermic; heat energy has been removed from the surroundings, making the container cold.
Chemistry
1 answer:
Trava [24]2 years ago
8 0

Answer:

Explanation:

Figure 6. An instant cold pack consists of a bag containing solid ammonium nitrate and a second bag of water. When the bag of water is broken, the pack becomes cold because the dissolution of ammonium nitrate is an endothermic process that removes thermal energy from the water.

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Which one is a true statement about endothermic reactions?
kicyunya [14]
In a endothermic reaction energy from an outside source is continuously being added.
6 0
3 years ago
Equal molar quantities of Ca2 and EDTA (H4Y) are added to make a 0.010 M solution of CaY2- at pH 10. The formation constant for
abruzzese [7]

Answer:

the concentration of free Ca2⁺ in this solution is 7.559 × 10⁻⁷

Explanation:

Given the data in the question;

Ca^{2+ + y^{4- ⇄  CaY^{2-

Formation constant Kf

Kf = CaY^{2- / ( [Ca^{2+][y^{4-] ) = 5.0 × 10¹⁰

Now,

[y^{4-] = \alpha _4CH_4Y; ∝₄ = 0.35

so the equilibrium is;

Ca^{2+ + H_4Y ⇄  CaY^{2- + 4H⁺

Given that; CH_4Y = Ca^{2+     { 1 mol Ca^{2+  reacts with 1 mol H_4Y  }

so at equilibrium, CH_4Y = Ca^{2+ = x

∴

Ca^{2+ + y^{4- ⇄  CaY^{2-

x        + x         0.010-x

since Kf is high, them x will be small so, 0.010-x is approximately 0.010

so;

Kf = CaY^{2- / ( [Ca^{2+][y^{4-] ) =  CaY^{2- / ( [Ca^{2+][\alpha _4CH_4Y] )  = 5.0 × 10¹⁰

⇒ CaY^{2- / ( [Ca^{2+][\alpha _4CH_4Y] )  = 5.0 × 10¹⁰

⇒ 0.010 / ( [x][ 0.35 × x] )  = 5.0 × 10¹⁰

⇒ 0.010 / 0.35x²  = 5.0 × 10¹⁰

⇒ x² = 0.010 / ( 0.35 × 5.0 × 10¹⁰ )

⇒ x² = 0.010 / 1.75 × 10¹⁰

⇒ x² = 0.010 / 1.75 × 10¹⁰

⇒ x² = 5.7142857 × 10⁻¹³

⇒ x = √(5.7142857 × 10⁻¹³)

⇒ x = 7.559 × 10⁻⁷

Therefore, the concentration of free Ca2⁺ in this solution is 7.559 × 10⁻⁷

8 0
3 years ago
An unknown radioactive substance has a half-life of 3.20hours . If 46.2g of the substance is currently present, what mass A0 was
iogann1982 [59]

Answer:

a) a0 was 46.2 grams

b) It will take 259 years

c) The fossil is 1845 years old

Explanation:

<em>An unknown radioactive substance has a half-life of 3.20hours . If 46.2g of the substance is currently present, what mass A0 was present 8.00 hours ago?</em>

A = A0 * (1/2)^(t/h)

⇒ with A = the final amount = 46.2 grams

⇒ A0 = the original amount

⇒ t = time = 8 hours

⇒ h = half-life time = 3.2 hours

46.2 = Ao*(1/2)^(8/3.2)

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<em>Americium-241 is used in some smoke detectors. It is an alpha emitter with a half-life of 432 years. How long will it take in years for 34.0% of an Am-241 sample to decay?</em>  

t = (ln(0.66))-0.693) * 432 = 259 years

It will take 259 years

<em>A fossil was analyzed and determined to have a carbon-14 level that is 80% that of living organisms. The half-life of C-14 is 5730 years. How old is the fossil?</em>

<em />

t = (ln(0.80))-0.693) * 5730 = 1845

The fossil is 1845 years old

7 0
3 years ago
Question 3 When the population size decreases over time, the total number of births the total number of deaths. O less than O eq
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The population decreases when the birth rate is less than the death rate.
4 0
3 years ago
g Glycolysis is the process by which energy is harvested from glucose by living things. Several of the reactions of glycolysis a
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Answer:

A and B are unfavorable reactions.

Explanation:

In chemical thermodynamics, an endergonic reaction  is also called a nonspontaneous reaction or an unfavorable reaction. it's a chemical reaction in which the change in free energy is positive, and energy is absorbed.

In chemical thermodynamics, an exergonic reaction  is also called a spontaneous reaction or a favorable reaction. it's a chemical reaction in which the change in free energy is negative.

ΔG>0

If the Gibbs  free energy of the reaction is positive than the reaction will be non spontaneous .

If the Gibbs  free energy of the reaction is negative than the reaction will be spontaneous

Gibbs free energy is an energy which that can be use to convert into useful work.

ΔG=ΔH-TΔS

with ΔG= Gibbs free energy

with ΔH =  enthalpy of reaction

with T = temperature of eh reaction

ΔS = Entropy change

The reaction A: Pi+glucose⟶glucose-6-phosphate+H2O

The ΔG is positive. This is an nonspontaneous reaction or an unfavorable reaction

The reaction B: Pi+fructose-6-phosphate⟶fructose-1,6-bisphosphate+H2O

The ΔG is positive. This is an nonspontaneous reaction or an unfavorable reaction.

The reaction C: ATP+H2O⟶ADP+Pi

The ΔG is negative. This is a spontaneous reaction or a favorable reaction.

A and B are unfavorable reactions.

6 0
3 years ago
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