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4 years ago

Which statement about exothermic reactions is accurate?

Chemistry

2 answers:

frosja888 [35]4 years ago

6 0

Answer:

A) As reactants form products, the potential energy decreases.

Explanation:

this is correct on ed-genuity, hope this helps! :)

ki77a [65]4 years ago

4 0

Answer is: As reactants form products, the potential energy decreases.

There are two types of reaction:

1) Endothermic reaction (chemical reaction that absorbs more energy than it releases).

2) Exothermic reaction (chemical reaction that releases more energy than it absorbs).

For example, balanced chemical reaction:

C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O ΔrH= -1370 kJ/mol.

This reaction is exothermic reaction (heat is released), so products have less potential energy and energy is transerred to surroundings.

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When 2.50 g of an unknown weak acid (ha) with a molar mass of 85.0 g/mol is dissolved in 250.0 g of water, the freezing point of

baherus [9]

When dT = Kf * molality * i
= Kf*m*i
and when molality = (no of moles of solute) / Kg of solvent
= 2.5g /250g x 1 mol /85 g x1000g/kg
=0.1176 molal
and Kf for water = - 1.86 and dT = -0.255
by substitution
0.255 = 1.86* 0.1176 * i
∴ i = 1.166
when the degree of dissociation formula is: when n=2 and i = 1.166
a= i-1/n-1 = (1.166-1)/(2-1) = 0.359 by substitution by a and c(molality) in K formula
∴K = Ca^2/(1-a)
= (0.1176 * 0.359)^2 / (1-0.359)
= 2.8x10^-3

5 0

3 years ago

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Georgia [21]

I’m not your just blind. I’m sorry

8 0

3 years ago

Each compound listed is soluble in water. For each compound, do you expect the resulting aqueous solution to conduct electrical

Strike441 [17]

Answer:

See below in bold.

Explanation:

a) Yes because it is an ionic compound. Forms ions in water solution.

b) This is an alcohol with covalent bonds it does not ionise in water - no.

c) Yes this forms ions in water solution.

d) This is a sugar and does not ionise so No.

5 0

3 years ago

We drop a cube of ice into a glass of water. The mass of the cube of ice is 33.1 g and its initial temperature is −10.2∘C. The m

Nastasia [14]

Answer: The final temperature (T) will be;

16.23°c

Explanation: To find the final temperature of any mixture of substance with an initial temperature use the formula;

M1c(T-T1) + M2c(T-T2)=0

c is the specific heat capacity of the two different substance, but because ice and water are the same, we assume c to be 1

T= final temperature of the mixture

T1= initial temperature of the ice= -10.2°c

T2= initial temperature of the water= 19.7°c

M1= mass of ice= 33.1g

M2= mass of water= 251g

Using the formula above

33.1(T-(-10.2)) + 251(T-19.7)=0

Solving out the bracket

33.1T + 337.62 + 251T - 4944.7 = 0

Collecting like terms to both side of the equation and solving

33.1T + 251T = 4944.7 - 33.62

284.1T = 4607.08

T = 4607.08÷284.1 = 16.23°c

6 0

3 years ago

A solution of bleach has about 1.5 g of NaOCl dissolved in 220 mL of solution. What is the molarity?

ale4655 [162]

Answer:

0.091 mol/L

Explanation:

Molarity of a substance , is the number of moles present in a liter of solution .

M = n / V

M = molarity ( unit = mol / L or M )

V = volume of solution in liter ( unit = L ),

n = moles of solute ( unit = mol ),

Moles is denoted by given mass divided by the molecular mass ,

Hence ,

n = w / m

n = moles ,

w = given mass ,

m = molecular mass .

From the data of the question , it is given that ,

w = 1.5 g

V = 220 mL

Since ,

1 mL = 1/1000L

V = 0.220 L

As we known , the mass of bleach NaOCl is ,

m = 74.44 g/mol

from the above equation , moles can be calculated as -

n = w / m

n = 1.5g / 74.44 g/mol

n = 0.0201 mol

Molarity of the solution is calculated as ,

M = n / V

M = 0.0201 mol / 0.220 L

M = 0.091 mol/L

4 0

4 years ago