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The diagram shows the potential energy changes for a reaction pathway. (10 points)

Part 1: Does the diagram illustrate an endothermic or an exothermic reaction? Give reasons in support of your answer.

Part 2: Describe how you can determine the total change in enthalpy and activation energy from the diagram and if each is positive or negative.

Answer:

[Na⁺] = 1.99 M

Explanation:

Na₂S is a ionic salt that can be dissociated.

Dissociation equation is:

Na₂S  →  2Na⁺  +  S⁻²

1 mol of sodium sulfide can give 2 moles of sodium cation.

We convert moles of salt: 78 g . 1mol / 78.06 g = 0.999 moles

As ratio is 1:2, after dissociation we have (0.999 . 2) = 1.998 moles of Na⁺

Molarity is a type of concentration.

It indicates moles of solute in 1 L of solution and in this case, we have 1 L as final voulme.

Moles of Na⁺ are 1.998 moles. Then molarity (mol/L) is:

M =1.99 mol/L  

Explanation:

here is your answer

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Answer:

The number of moles of H₃PO₄ that reacted is 0.000343 moles

Note: Some data is missing. Data from the attachment is used for the calculationsinnthe explanation below.

Explanation:

The reaction is a neutralization reaction between NaOH and H₃PO₄. The equation of the reaction is given as follows:

3 NaOH + H₃PO₄ ---> Na₃PO₄ + 3 H₂O

The molarity of the NaOH solution is 0.238 mol/L.

Average volume of NaOH used during the titration to arrive to endpoint = (4.6 + 3.9 + 4.5) mL / 3 = 4.33 mL

Molarity is defined ratio of the number of moles of solute to the volume of solution. Mathematically, molarity = number of moles/volume in Litres

Number of moles of NaOH reacted = 0.238 mol/L × (4.33mL × 1 L/1000 mL)

Number of moles of NaOH = 0.00103 moles

From the equation of the reaction, 3 moles of NaOH reacts with 1 mole of H₃PO₄

0.00103 moles of NaOH will react with 0.00103 x 1/3 moles of H₃PO₄ = 0.000343 moles of H₃PO₄.

Therefore, number of moles of H₃PO₄ that reacted is 0.000343 moles

Answer:

11

1. 6.02×10 23

this is the answer Hope it helps you

Answer:

243.75 mL

Explanation:

In 1min 32.5 mL of oxygen

In 7.5 min electrolysis of water produces

(32.5mL × 7.5 min)/ 1min

= 243.75mL

Answer:

[tex]Q\approx6.4~kJ[/tex]

Explanation:

Quantity of heat required by 10 gram of ice initially warm it from -5°C to 0°C:

[tex]Q_1=m.C_s.\Delta T[/tex]

here;

mass, m = 10 g

specific heat capacity of ice, [tex]C_s=2.09~J.g^{-1}.^{\circ}C^{-1}[/tex]

change in temperature, [tex]\Delta T=(5-0)=5^{o}C[/tex]

[tex]Q_1=10\times2.09\times 5[/tex]

[tex]Q_1=104.5~J[/tex]

Amount of heat required to melt the ice at 0°C:

[tex]Q_2=m.\Delta H_{fus}[/tex]

where, [tex]\Delta H_{fus}=6020~J/mol[/tex]

we know that no. of moles is = (wt. in gram) [tex]\div[/tex] (molecular mass)

[tex]Q_2=\frac{10}{18} \times 6020[/tex]

[tex]Q_2=3344.44~J[/tex]

Now, the heat required to bring the water to 70°C from 0°C:

[tex]Q_3=m.C_L.\Delta T[/tex]

specific heat of water, [tex]C_L=4.18~J/g/^oC[/tex]

change in temperature, [tex]\Delta T=(70-0)=70^oC[/tex]

[tex]Q_3=10\times 4.18\times 70[/tex]

[tex]Q_3=2926~J[/tex]

Therefore the total heat required to warm 10.0 grams of ice at -5.0°C to a temperature of 70.0°C:

[tex]Q=Q_1+Q_2+Q_3[/tex]

[tex]Q=104.5+3344.44+2926[/tex]

[tex]Q=6374.94~J[/tex]

[tex]Q\approx6.4~kJ[/tex]

Answer:

the fraction of collisions with energy greater than Eact

Explanation:

The activation energy of a reaction stands as a sort of energy barrier between reactants and products. It is only reactants that possesses energy greater than the activation energy that can be converted from reactants to products.

When the temperature of the system is increased, more particles acquire energy greater than the activation energy. Hence, the fraction of collisions with energy greater than the activation energy increases so the rate of reaction increases likewise.

Answer:

Explanation:

B

Answer:

2.39x10⁻⁴ moles

Explanation:

As the problem asks us the number of moles of KIO₃ that were titrated, all that is required of us is to calculate how many moles of KIO₃ are there in 23.92 mL of a 0.0100 M solution (All moles in the samples are titrated).

We can do so by using the definition of molarity:

converting 23.92 mL ⇒ 23.92 / 1000 = 0.02392 L

Answer:

5.0molO

Explanation:

To find the moles of oxygen in 2.5 moles of caffeine, we will first research caffeine's molecular formula: C8H10N4O2. From the molecular formula, we can see there are 2 oxygen atoms in every 1 molecule of C8H10N4O2.We can therefore multiply by the following mole ratio to get the moles of oxygen.

2.5molC8H10N4O2×2molO/1molC8H10N4O2 = 5.0molO.

Answer:

F. When everyone is together it gets hotter

Explanation:

Answer:

c. it lies near the equator

Answer: The new concentration of the solution is 0.143 M.

Explanation:

Given: [tex]V_{1}[/tex] = 300.0 mL,    [tex]M_{1}[/tex] = 0.335 M

[tex]V_{2}[/tex] = 700.0 mL,         [tex]M_{2}[/tex] = ?

Formula used is as follows.

[tex]M_{1}V_{1} = M_{2}V_{2}[/tex]

Substitute values into the above formula as follows.

[tex]M_{1}V_{1} = M_{2}V_{2}\\0.335 M \times 300.0 mL = M_{2} \times 700.0 mL\\M_{2} = 0.143 M[/tex]

Thus, we can conclude that the new concentration of the solution is 0.143 M.

Explanation:

Answer:

pKa = 4.89.

Explanation:

We can solve this problem by using the Henderson-Hasselbach equation, which states:

pH = pKa + log [tex]\frac{[A^-]}{[HA]}[/tex]

In this case [A⁻] is the concentration of sodium benzoate and [HA] is the concentration of benzoic acid.

We input the given data:

4.63 = pKa + log [tex]\frac{0.16}{0.29}[/tex]

And solve for pKa:

pKa = 4.89

Answer:

The molar concentration of the H₂SO₄ solution is 0.28 M

Explanation:

Molar concentration = number of moles / volume in litres

Number of moles = molar concentration × volume

From the equation of reaction, molar ratio of acid to base = 1 : 2

Using the formula; Na/Nb = CaVa/CbVb

Where Na is the number of moles of acid; Nb = number of moles of base; Ca = concentration of acid; Va = volume of acid; Cb = concentration of base; Vb = volume of base; Na/Nb = mole ratio of acid to base

Substituting the given values in the equation:

1/2 = Ca × 25.18 / 0.93 × 14.92

Ca = 0.93 × 14.92/ 25.18 × 2

Ca = 0.28M

Therefore, the molar concentration of the H₂SO₄ solution is 0.28 M

Answer:

carrying capacity

Explanation:

Thus, the carrying capacity is the maximum number of individuals of a species that an environment can support. Population size decreases above carrying capacity due to a range of factors depending on the species concerned, but can include insufficient space, food supply, or sunlight.

Answer:

Please find the complete solution in attached file.

Explanation:

Periodic law is the the properties of the elements that repeat in a regular way as the atomic numbers increase.

Periodic chart organized collection of all chemical elements arranged roughly according to increasing atomic weight. The periodic recurrence of several features in the elements was originally identified by Dmitry I. Mendeleyev in 1869.

1. This is a vertical arrangement of elements in the periodic table   group

2. This is a horizontal arrangement of elements in the periodic table   period

3. The properties of the elements repeat in a regular way as the atomic numbers increase periodic law

4. Element 19 begins this arrangement in the periodic table period

5. The chemical properties of elements 12, 20, and 38 demonstrate this principle.  periodic law

Therefore, periodic law is the the properties of the elements that repeat in a regular way as the atomic numbers increase.

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Explanation:

here are the answers. Note that because the pressure is constant, you can use Gay Lussac's formula

Answer:

Endothermic

Explanation:

Endothermic reaction is one in which the enthalpy increases. What this implies is that, it is a closed system which absorbs heat from its surroundings and thus after reaction become cooler than prior to the reaction.

In this case, the mixture of the two liquids feel colder to touch. Thus, it is an endothermic reaction from the definition earlier given.

Answer:

2700 kg/m³

Explanation:

First let's convert 2.7 g/cm³ to kg/cm³, keeping in mind that 1 kilogram equals 1000 grams:

Finally we need to convert 0.0027 kg/cm³ to kg/m³, keeping in mind that 1 meter equals 100 centimeters, as follows:

The answer is 2700 kg/m³.

Answer:

sodium ions and chloride ions

chloride ion

sodium ion

Explanation:

Ionic substances are composed of ions. When you dissolve an Ionic substance in water, the ions that compose the substance together with water molecules are present in solution.

Hence, when sodium chloride is dissolved in water, sodium ions and chloride ions are released in solution.

Water has a dipole moment. Hence, the chloride ions are attracted to hydrogen (the positive end of the dipole) while sodium ions are attracted to oxygen (the negative end of the dipole).

This is how the solid is dissolved in water.

When sodium chloride, NaCl , dissolves in water, the solution contains sodium and chloride ions in addition to the water solvent. The partial charges in water help dissolve the compound as the hydrogen end of water is attracted to the chloride ions and the oxygen end is attracted to the sodium ions.

Those molecules in which positive ion as well as negative ion is present, will show solubility in water.

Sodium chloride (NaCl) is an ionic compound, which dissociates into sodium ion and chloride ion in the water. As in the water H⁺ ions are present which get attracted towards the chloride ions (Cl⁻) and hydroxide ion (OH⁻ ion) get attracted towards the sodium ions (Na⁺) and show complete dissolution.

Hence correct answers are sodium and chloride ions, chloride ion and sodium ion.

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Answer:

Magnesium.

Explanation:

Because it is in group II

Answer:

6+9=15

mass number =15

mass number = no. protons + no. of neutrons

Answer:

a) Heat energy is absorbed.

Explanation:

What occurs in endothermic reactions?

a) Heat energy is absorbed. YES. This is the definition of an endothermic reaction.

b) Water is produced. NO. Endothermic refers to the heat absorbed and not to the products formed.

c) Oxygen is produced. NO. Endothermic refers to the heat absorbed and not to the products formed.

d) Heat energy is released. NO. This is known as an exothermic reaction.

Answer:

only one substrate could be converted to product by the enzyme

Explanation:

If an enzyme obeys the lock and key model, it then follows that the design of the enzyme is unique to a particular substrate.

Just as only the correct key can effectively fit into a lock, only the appropriate substrate whose design matches that of the enzyme can fit into the enzyme.

Owing to the lock and key model of enzyme activity, only one enzyme could interact with a substrate to yield particular product.

Answer:

double decomposition reaction