7.71 Classify each of the following as exothermic or endothermic:
a. CHÂ(g) + 2O₂(g) —^> CO₂(g) + 2H₂O(g) + 802 kJ
b. Ca(OH)₂(s) + 65.3 kJ →→→ CaO(s) + H₂O(l)
c. 2Al(s) + Fe₂O3(s) — Al₂O3(s) + 2Fe(s) + 850 kJ

From the calculations, the concentration of the acid is 0.24 M.

The term neutralization has to do with a reaction in which an acid and a base react to form salt and water only.

We have to use the formula;

CAVA/CBVB = NA/NB

CAVANB =CBVBNA

The equation of the reaction is; 2NaOH + H2SO4 ----> Na2SO4 + 2H2O

CA = ?

CB = 1.2 M

VA =  50 mL

VB = 20 mL

NA = 1

NB = 2

CA = CBVBNA/VANB

CA = 1.2 M * 20 mL * 1/ 50 mL * 2

CA = 0.24 M

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The empirical formula of the hydrocarbon is [tex]C_2H_3[/tex] if combustion of 8.60 g of a hydrocarbon produced 26.5 g of [tex]CO_2[/tex] and 12.2 g of [tex]H_2O[/tex].

A chemical formula showing the simplest ratio of elements in a compound rather than the total number of atoms in the molecule [tex]CH_2O[/tex] is the empirical formula for glucose.

1 mole of carbon dioxide contains a mass of 44 g, out of which 12 g are carbon.

Hence, in this case the mass of carbon in 8.46 g of [tex]CO_2[/tex]:

([tex]\frac{12}{44}[/tex]) × 8.46 = 2.3073 g

1 mole of water contains 18 g, out of which 2 g is hydrogen;

Therefore, 2.6 g of water contains;

([tex]\frac{2}{18}[/tex] × 2.6 = 0.2889 g of hydrogen.

Therefore, with the amount of carbon and hydrogen from the hydrocarbon, we can calculate the empirical formula.

We first calculate the number of moles of each,

Carbon = [tex]\frac{2.3073}{12}[/tex]  = 0.1923 moles

Hydrogen = [tex]\frac{0.2889}{1}[/tex]= 0.2889 moles

Then, we calculate the ratio of Carbon to hydrogen by dividing by the smallest number value;

            Carbon : Hydrogen

               [tex]\frac{0.1923}{0.1923}[/tex] : [tex]\frac{0.2889}{0.1923}[/tex]

                      1 :  1.5

                     (1 : 1.5) 2

                    = 2 : 3

Hence, the empirical formula of the hydrocarbon is [tex]C_2H_3[/tex].

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Answer:

A

Explanation:

Answer:

i believe its called A. periods

non-polar

Explanation :

Hydrogen and carbon have similar electronegativity values, so the C—H bond is not normally considered a polar covalent bond.

Answer:

CO2

Explanation:

100% CORRECT ON EDGE

The mass of water produced when 1.000 × 10³ g of LiOH is combined with 8.80 × 10² g CO₂  is 3.25 × 10² g H₂O.

Mass is defined as a dimensionless number used to describe the mass of a particle or item. The kilogram is the International System's (SI) preferred unit of mass (kg). Atoms make up everyday matter. A majority of an atom's mass is contained in its nucleus.

It is a neutralization process when lithium hydroxide and carbon dioxide combine to form water and lithium carbonate.

The reaction is [tex]\rm CO_2 + 2LiOH \rightarrow Li_2CO_3 + H_2O[/tex]

Neutralization reaction is defined as an acid and base reaction that produces an ionic molecule and potentially water.

Thus, the mass of water produced when 1.000 × 10³ g of LiOH is combined with 8.80 × 10² g CO₂  is 3.25 × 10² g H₂O.

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The phenomenon known as "salting-out" occurs at very high ionic strengths, when protein solubility declines as ionic strength rises. As a result, salting out may be used to segregate proteins according to how soluble they are in salt solutions.

Because large levels of sodium chloride disturb the bonds and structure of the active site, the rate of enzyme activity will gradually decrease as the concentration of sodium chloride rises. As a result, some of the active sites get denaturized and the starch loses its ability to attach to them. As more enzymes get denatured and eventually cease to function, enzyme activity will steadily wane.

A catalyst is a substance that increases the rate of a chemical reaction by lowering the activation energy without itself being consumed by the reaction.

C= 87.8 : 12 = 7.316

H= 12.2 : 1 = 12.2

C : H = 1 : 1.667 =  3 : 5

C₃H₅

The rate law uses the molar concentrations of reactants to determine the reaction rate. Hence, option (C) is the correct option

A rate law shows how the rate of a chemical reaction depends on reactant concentration.

For a reaction such as aA → products, the rate law generally has the form

rate = k[A]ⁿ,

where,

Typically, increased concentrations of reactants increases the speed of the reaction, because there are more molecules colliding and reacting with each other.

Hence , The rate law uses the molar concentrations of reactants to determine the reaction rate. Hence, option (C) is the correct option

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No matter how big or little a material is, its properties remain the same. Size, form, color, and mass are the qualities that distinguish a material from non-substances. All of these qualities, including size, shape, color, and mass, can be seen and measured. Some characteristics are physical, while others are chemical. Physical characteristics include mass, volume, density, and color.  Viscosity and solubility are examples of chemical qualities.

The northern slope will have the least precipitation if winds blow against a mountain from the south.

This is referred to as the degree of steepness on a surface such as rocky areas etc.

When wind blows on the southern part of a mountains, it gets stuck which is why the northern slope have the least precipitation.

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350 Kcal is equals to 350000 calorie and 1464400 Joule.

The equation for calculating the energy content of a food source via calorimetry is as follows: Energy (joules) = Mass of water (g) × 4.2 (J/gºC) × Temperature increase (ºC)

1 Kcal = 1000 calorie

Therefore,

35 Kcal = 350 x 1000

            = 350000 calorie

Now,

1 calorie = 4.184 joule

Therefore,

35000 calorie = 350000 x 4.184

                        = 1464400 joule

Hence, 350 Kcal is equals to 350000 calorie and 1464400 Joule.

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Answer:

The moles of H2 is 230-two hundred and thirty

The percent yield would be 68.3%

This is given as:

Percent yield = yield/theoretical yield x 100%

From the equation:

[tex]2SO_2(g) + O_2(g) -- > 2SO_3(g)[/tex]

The mole ratio of the reactants is 2;1

Mole of 705 g SO2 = 705/64 = 11.02 moles

Mole of 80 g O2 = 80/32 = 2.5 moles

O2 is limiting.

Mole ratio of O2 and SO3 = 1:2

Mole equivalent of SO3 = 2.5 x 2 = 5.0 moles

Mass of 5 moles SO3 = 5 x 80 = 400 grams

Percent yield = 400/586 = 68.3%

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Molar concentration of Zn2+ions in a solution is 3.481 mol/lit

The electrode potential value is 59mV

Temperature=298k

What is electrode potential?

equation formed- Zn → Zn2+ + 2e

              from Nernst equation-

E=E cell - 0.059 log [Zn2+]

[zn2+]=3.481 mol/lit

hence, Molar concentration of Zn2+ions in a solution is 3.481 mol/lit

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Decreasing the separation between the two magnets will result in increase in the magnetic force between two magnets.

This is referred to a substance which produces magnetic field and result in the attraction and repulsion of certain types  of things.

Increase in the separation will reduce the magnetic force and vice versa which is why option A was chosen.

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Answer:

Neither accurate not precise

Answer:

The elements which are in the group

Answer:

2.06M NaCl

Explanation:

Molarity is defined as a ratio of moles of the solute (the substance you're dissolving) to Liters of solution (the volume of the finished solution).  It uses the letter capital M as an abbreviation for the unit.

We're given values for both numbers (with the correct units already), so substitute, and calculate the number part:

[tex]\dfrac{n_{solute}}{V_{solution}}=\dfrac{3.09 [\text{mol NaCl}]}{1.50 [\text{L solution}]}=2.06\dfrac{[\text{mol NaCl}]}{[\text{L solution}]}=2.06[\text{M NaCl}][/tex]

Gneiss is a sedimentary rock and granite is a metamorphic rock. That is option A.

Rocks are geological hard materials that are made up of various types which include:

Therefore, Gneiss is a sedimentary rock and granite is a metamorphic rock.

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Answer:

C

Granite is formed due to the slow cooling of magma below Earth's surface and gneiss is formed due to metamorphosis.

Explanation:

I took the test!

The amount of nitrogen oxide in the air sample is determined as 7.01 ppb.

The amount of Nitrogen oxide (NO2) in the air in parts per billion (ppb) is calculated as follows;

12 micrograms of NO2 = 12 μg = 12 x 10⁻⁶ g

PV = nRT

V = nRT/P

Where;

n = m/M

M = molar mass of NO2 = 46

n =  12 x 10⁻⁶/46

n = 2.73 x 10⁻⁷ mole

V = (2.73 x 10⁻⁷ x 0.082057 x 313)/(1)

V = 7.01 x 10⁻⁶ L

V =  7.01 x 10⁻⁹ m³

= (Volume of NO2)/(volume of air) x 10⁹

= (7.01 x 10⁻⁹)/(1) x  10⁹

= 7.01 ppb

Thus, the amount of nitrogen oxide in the air sample is determined as 7.01 ppb.

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Answer:

(a) 1s2 2s1

Explanation:

Electron configurations of atoms are in their ground state when the electrons completely fill each orbital before starting to fill the next orbital.

It's important to know how to read and interpret the notation.

For example, the first part of option (a) says "1s2"

It important to know which orbitals are in each shell:

So, it's also important to know how many electrons can be in each orbital in order to know if they are full or not.  The electrons should fill up these orbitals for each level, in this order:

For option (a):

This is in it's ground state.

For option (b):

Because the 3s orbital has an electron, but the lower 2p before it isn't full.  This is NOT in it's ground state.

For option (c):

Although the 2p orbital is full, since the 2s orbital before it was not yet full, this is NOT in it's ground state.

For option (d):

Again, despite that the final orbital (in this case, the 2s orbital), is full, since the 1s orbital before it was not yet full, this is NOT in it's ground state.

It takes 31 s for 1.27 M H₃PO₄ to decrease its concentration to 7.0% of its initial value following first-order kinetics.

First-order kinetics occur when a constant proportion of a reactant disappears per unit time.

Let's consider the following first-order kinetics reaction with a rate constant k = 0.086 s⁻¹.

2 H₃PO₄(aq) = P₂O₅(aq) + 3 H₂O(aq)

Given the initial concentation is [H₃PO₄]₀ = 1.27 M, the concentration representing 7.0% of this value is:

[H₃PO₄] = 7.0% × 1.27 M = 0.089 M

We can calculate the time elapsed (t) using the following expression.

ln ([H₃PO₄]/[H₃PO₄]₀) = - k × t

ln (0.089 M/1.27 M) = - 0.086 s⁻¹ × t

t = 31 s

It takes 31 s for 1.27 M H₃PO₄ to decrease its concentration to 7.0% of its initial value following first-order kinetics.

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Answer: A. A bond in which molecules share electrons

Answer:

a chemical compound