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2 years ago

For ΔH soln to be very small, what quantities must be nearly equal in magnitude? Will their signs be the same or opposite?

Chemistry

1 answer:

eimsori [14]2 years ago

5 0

A solute dissolves in excess solvent to form a solution:

solute + solvent → solution

<h3>What is the Enthalpy and their relation ? </h3>

A thermodynamic system's enthalpy, which is one of its properties, is calculated by adding the system's internal energy to the product of its pressure and volume. It is a state function that is frequently employed in measurements of chemical, biological, and physical systems at constant pressure, which the sizable surrounding environment conveniently provides.

A solution is a uniform mixture of two or more components that can exist in the solid, liquid, or gas phases. The amount of heat that is released or absorbed during the dissolving process is known as the enthalpy change of solution (at constant pressure).

There are two possible values for this enthalpy of solution ( H solution ) : positive (endothermic) and negative (exothermic). It is most straightforward to visualize a hypothetical three-step process occurring between two substances while trying to grasp the enthalpy of solution. The solute is one substance; let's call it A. The solvent is the second component; let's call it B.

The initial procedure exclusively affects the solute A and calls for disabling all intramolecular forces holding it together. This indicates that the molecules of the solute separate. This process' enthalpy is known as H1. Since breaking interactions requires energy, this is always an endothermic process, hence H1>0.

Their sign will be opposite.

To know more about Enthalpy please click here : brainly.com/question/14047927

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You might be interested in

if kept at a constant temperature, what is the concentration at 865s if the initial concentration was 0.0225M

Anestetic [448]

Answer:

$[SO_2Cl_2]=0.0175M$

Explanation:

Hello!

In this case, considering that the decomposition reaction of SO2Cl2 is first-order, we can write the rate law shown below:

$r=-k[SO_2Cl_2]$

We also consider that the integrated rate law has been already reported as:

$[SO_2Cl_2]=[SO_2Cl_2]_0exp(-kt)$

Thus, by plugging in the initial concentration, rate constant and elapsed time we obtain:

$[SO_2Cl_2]=0.0225Mexp(-2.90x10^{-4}s^{-1}*865s)$

$[SO_2Cl_2]=0.0175M$

Best regards!

8 0

2 years ago

You decided to prepare a phosphate buffer from solid sodium dihydrogen phosphate (NaH2PO4) and disodium hydrogen phosphate (Na2H

KIM [24]

Answer:

For disodium hydrogen phosphate:

5.32g Na2HPO4

For sodium dihydrogen phosphate:

7.65g Na2HPO4

Explanation:

First, you have to put all the data from the problem that you going to use:

-NaH2PO4 (weak acid)

-Na2HPO4 (a weak base)

-Volume = 1L

-Buffer pH = 7.00

-Concentration of [NaH2PO4 + Na2HPO4] = 0.100 M

What we need to find the pKa of the weak acid, in this case NaH2PO4, for that you need to find the Ka (acid constant) of NaH2PO4, and for this we use the pKa of the phosphoric acid as follow:

H3PO4 = H2PO4 + H+ pKa1 = 2.14

H2PO4 = HPO4 + H+ pKa2 = 6.86

HPO4 = PO4 + H+ pKa3 = 12.4

So, for the preparation of buffer, you need to use the pKa that is near to the value of the pH that you want, so the choice will be:

pKa2= 6.86

Now we going to use the Henderson Hasselbalch equation for the pH of a buffer solution:

pH = pKa2 + log [(NaH2PO4)/(Na2HPO4)]

The solution of the problem is attached to this answer.

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7 0

3 years ago

Through electrolysis, a student collects 6.6 g of hydrogen gas and 52.4 g of oxygen gas. The reaction was allowed to proceed to

Kaylis [27]

Answer: 59 grams

Explanation:

According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

$2H_2O\rightarrow 2H_2+O_2$

Given: mass of hydrogen = 6.6 g

mass of oxygen = 52.4 g

Mass of products = Mass of hydrogen + mass of oxygen = 6.6 +52.4 = 59 g grams

Thus mass or reactant = mass of water

Mass of reactants = mass of products = 59 g

Thus the mass of water initially present was 59 g.

3 0

3 years ago

An atom that has lost one or more electrons is a(n) _______

kompoz [17]

Answer:

An atom that loses one or more valence electrons to become a positively charged ion is known as a cation, while an atom that gains electrons and becomes negatively charged is known as an anion.

8 0

3 years ago

Read 2 more answers

How much energy is required to vaporize 155 g of butane at its boiling point? the heat of vaporization for butane is 23.1 kj/mol

netineya [11]

The energy required to vaporize 155 g of butane at its boiling point: 61,723 kJ

<h3>Further explanation</h3>

Enthalpy is the amount of system heat at constant pressure.

The enthalpy is symbolized by H, while the change in enthalpy is the difference between the final enthalpy and the initial enthalpy symbolized by ΔH.

$\large{\boxed{\boxed{\bold{\Delta H=H_{End}-H_{First}}}}$

Delta H reaction (ΔH) is the amount of heat change between the system and its environment

(ΔH) can be positive (endothermic = requires heat) or negative (exothermic = releasing heat)

The standard unit is kilojoules (kJ)

The enthalpy change symbol (ΔH) is usually written behind the reaction equation.

Change in Standard Evaporation Enthalpy (ΔH vap) is a change in enthalpy at the evaporation of 1 mol liquid phase to the gas phase at its boiling point and standard pressure.

Examples of water evaporation:

H₂O (l) ---> H₂O (g); ΔH vap = + 44kJ

The enthalpy of evaporation is positive because its energy is needed to break the attraction between molecules in a liquid