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4 years ago

In an endothermic reaction what is true of the enthalpy

Chemistry

1 answer:

charle [14.2K]4 years ago

4 0

Answer is: a) is has increased.

There are two types of reaction:

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

For example, the breakdown of ozone is an endothermic process. Ozone has lower energy than molecular oxygen (O₂) and oxygen atom, so ozone need energy to break bond between oxygen atoms.

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

For example, ΔH(reaction) = -225 kJ/mol; this is exothermic reaction.

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4 Weathering Assessment

Leni [432]

Answer:

This is an example of a physical change because the ice cubes began to melt.

Explanation:

The above is the right answer to the question about the dissolution of the whole mixture mentioned in the excerpts above.

6 0

3 years ago

(01.01 LC)

Vadim26 [7]

The answer to this question is B

4 0

3 years ago

Read 2 more answers

A certain amount of hydrogen peroxide was dissolved in 100. mL of water and then titrated with 1.68 M KMnO4. What mass of H2O2 w

Stels [109]

Answer:

see explanation below

Explanation:

First to all, this is a redox reaction, and the reaction taking place is the following:

2KMnO4 + 3H2SO4 + 5H2O2 -----> 2MnSO4 + K2SO4 + 8H2O + 5O2

According to this reaction, we can see that the mole ratio between the peroxide and the permangante is 5:2. Therefore, if the titration required 21.3 mL to reach the equivalence point, then, the moles would be:

MhVh = MpVp

h would be the hydrogen peroxide, and p the permanganate.

But like it was stated before, the mole ratio is 5:2 so:

5MhVh = 2MpVp

Replacing moles:

5nh = 2MpVp

Now, we just have to replace the given data:

nh = 2MpVp/5

nh = 2 * 1.68 * 0.0213 / 5

nh = 0.0143 moles

Now to get the mass, we just need the molecular mass of the peroxide:

MM = 2*1 + 2*16 = 34 g/mol

Finally the mass:

m = 0.0143 * 34

m = 0.4862 g

8 0

3 years ago

A sucrose solution is prepared to a final concentration of 0.250 M . Convert this value into terms of g/L, molality, and mass %.

MArishka [77]

Answer:

A. 85.6 g

= 0.0856 kg.

B. 0.00027 mol/g

= 0.27 mol/kg.

C. 8.39 %

Explanation:

Given:

Molar concentration = 0.25 M

Molar weight of sucrose = 342.296 g/mol

Density of solution = 1.02 g/mL

Mass of water = 934.4 g.

Density in g/l = 1.020 g/ml * 1000ml/1 l

= 1020 g/l

Mass of solution in 1 l of solution = 1020 g

Mass of solution = mass of solvent + mass of solute

Mass of sucrose = 1020 - 934.4

= 85.6 g of sucrose in 1 l of solution.

Density of sucrose = mass/volume

= molar mass/molar concentration

= 342.296 * 0.25

= 85.6 g/l

Number of moles = mass/molar mass

= 85.6/342.296

= 0.25 mol

Molality = number of moles of solute/mass of solvent

= 0.25/934.4

= 0.00027 mol/g

% mass of sucrose = mass of sucrose/total mass of solution * 100

= 85.6/1020 * 100

= 8.39 %

6 0

3 years ago

Are the following statements true or false? (a) Formal charges represent an actual separation of charges. true false (b) ΔH o rx

katrin [286]

Answer:

Explanation:

A) Formal charges represent an actual separation of charges.(FALSE)

(B) ΔHo rxn can be estimated from the bond enthalpies of reactants and products.(TRUE)

C)All second-period elements obey the octet rule in their compounds(FALSE).

(D)The resonance structures of a molecule can be separated from one another in the laboratory.(FALSE)

Bond enthalpy which is also reffered to as bond energy is the amount of energy that is required to break one mole of a bond.

taking the single bond between Oxygen and Hydrogen into considerationthe bond energy between their single bond is 463 kJ/mol.

formal charge is used for the comparison of the number of electrons present around an atom in a particular molecule with the number of electrons present around a neutral

3 0

3 years ago