When 14.8 g KOH is dissolved in 85.6 g of water in a coffee-cup calorimeter, the temperature rises from 19.3 °C to 32.76 °C. What is the enthalpy change per gram of potassium hydroxide dissolved in the water?

Answers

Answer 1

Answer:

This question is incomplete, the complete question is; assuming that the solution has a specific heat of 4.18 J/g°C

The answer is 381.67 J/g

Explanation:

Enthalpy change denoted by ΔH can be calculated using the formula;

ΔH = m × c × ΔT

Where; m= mass of reactants

c= specific heat

ΔT = change in temperature

ΔT = T2 - T1

ΔT = 32.76 - 19.3

ΔT = 13.46 °C

mass of reactants= 85.6 + 14.8 = 100.4g, c = 4.18J/g°C

Hence; ΔH = m × c × ΔT

ΔH = 100.4 × 4.18 × 13.46

ΔH = 5648.78J

Enthalpy change per gram of potassium hydroxide dissolved in the water is;

ΔH = 5648.78/14.8

ΔH = 381.67 J/g

Answer 2

The enthalpy change per gram of potassium hydroxide dissolved in the water is 382 J/g

How to determine the heat Mass (M) = 14.8 + 85.6 = 100.4 gInitial temperature (T₁) = 19.3 °C Final temperature (T₂) = 32.76 °CChange in temperature (ΔT) = 32.76  – 19.3 = 13.46 °C Specific heat capacity (C) = 4.184 J/gºC Heat (Q) =?

Q = MCΔT

Q = 100.4 × 4.184 × 13.46

Q = 5654.19 J

How to determine the enthalpy change ΔHHeat (Q) = 5654.19 JMass of KOH (m) = 14.8 gEnthalpy change (ΔH) =?

ΔH = Q / g

ΔH = 5654.19 / 14.8

ΔH = 382 J/g

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Related Questions

There are________
neutrons in the stable isotope of rhenium (Re-
185)

A.134
B.90
C.125
D.110

Answers

A.134 sorry if it’s wrongggg

There are 110 neutrons in the stable isotope of rhenium. The correct option is D.

What are neutrons?

A neutron is a subatomic particle that exists in the nucleus of all atoms except simple hydrogen. The name of the particle comes from the fact that it has no electrical charge; it is neutral. Neutrons have a very high density.

With the exception of the single-proton hydrogen nucleus, nuclei require neutrons to be stable. Neutrons are abundantly produced during nuclear fission and fusion.

Through mainly the process of fission, fusion, as well as neutron capture processes, they are a major contributor to the nucleosynthesis of chemical elements within stars.

The element rhenium-185 is made up of 75 protons, 110 neutrons, and 75 electrons. The element rhenium-187 is made up of 75 protons, 112 neutrons, and 75 electrons.

Thus, the correct option is D.

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The absolute temperature of a fixed mass of ideal gas is tripled while its volume remains constant. The ratio of the final pressure of the gas to its initial pressure is

Answers

Answer:

3 : 1

Explanation:

The following data were obtained from the question:

Initial temperature (T₁) = T

Initial pressure (P₁) = P

Final temperature (T₂) = 3T

Final pressure (P₂) =..?

Since the volume is constant, we shall use the following formula P₁ /T₁ = P₂ /T₂ to obtain the final pressure. This is illustrated below:

P₁ /T₁ = P₂ /T₂

P/T = P₂ /3T

Cross multiply

T × P₂ = P × 3T

Divide both side by T

P₂ = P × 3T /T

P₂ = P × 3

P₂ = 3P

Therefore, the final pressure is tripled.

Finally, we shall determine the ratio of the final pressure to the initial pressure as follow:

Initial pressure (P₁) = P

Final pressure (P₂) = 3P

Final pressure (P₂) : Initial pressure (P₁)

P₂ : P₁ => 3P/P

P₂ : P₁ => 3 : 1

Therefore, the ratio of the final pressure to the initial pressure is 3 : 1

Given sulfur has an electron configuration of 1s22s22p63s23p4, what oxidation numbers would you expect for sulfur? (Hint: Think about how to achieve a full outer shell.)

Answers

Explanation:

1s2 2s2 2p6 3s2 3p4

Oxidation number refers to the number of electrons that an atom gains or loses as it forms a chemical bond with another element.

From the electronic configuration above, it is expected that sulphur has oxidation number of 2. This is because the p orbital can hold a maximum of 6 electrons. However, in the electronic configuration it is just holding 4. To complete it, it needs to gain 2 more electrons.

Answer:

+4, +6, –2

Explanation:

what is the volume occupied by 6.022 X 1​0*23molecules of any gas at STP.

Answers

1 mole of compound contains numbers of molecule
Step 1:- one mole of a compound occupies 22.4L of volume. Which means the number of molecules occupy 22.4 L of volume

{22.4L}

What are the components of the water-based carbon cycle?

Answers

Answer:

Carbon gets incorporated into marine organisms as organic matter or structural calcium carbonate.

Explanation:

ur welcome

Carbon gets incorporated into marine organisms as organic matter or structural calcium carbonate.

What is the carbon cycle?

The carbon cycle describes how carbon moves between the atmosphere, soils, living creatures, the ocean, and human sources.

Carbon gets incorporated into marine organisms as organic matter or structural calcium carbonate. When organisms die, their dead cells, shells and other parts sink into deep water. Decay releases carbon dioxide into this deep water.

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Can someone please help with chemistry? Lead has a density of 10.5 g/cm^3. What is the diameter of a lead ball that has a mass of 500.0g? Report your answer in cm.

Answers

Density = Mass / Volume

10.5 = 500 / x

10.5x = 500

x = 50 cm^3 (1 sig fig) volume of the sphere

Volume of a sphere = 4/3 pi r^2

pi = 3.14 r = radius

50 = 4/3 pi r^3

50•3/4 = pi r^3

37.5 = pi r^3

37.5/pi = r^3

11.9 = r^3

cube root(11.9) = r

2.3 = r

Diameter = 2•radius

Diameter = 2 • 2.3

Diameter = 5 cm (1 sig fig) diameter



How are the Celsius, Kelvin, and Fahrenheit scales similar? How are they different?

Answers

celcius and Fahrenheit are the same at -40 degrees since the scales converge . celcius and Kelvin become Equal at high temperatures as the difference. of 273. 15 between them gets lost in the noise . 0 degree Celsius is Equal to 32degrees Fahrenheit.

A scuba tank has pressure of 195 kpa at temperature 10 c the volume of the tank is 350 L how many grams of air ins in the tank?

Answers

Answer:

[tex]m=840.88g[/tex]

Explanation:

Hello,

In this case, considering the ideal gas equation as:

[tex]PV=nRT[/tex]

We can first compute the moles of air at the given conditions of 195 kPa (1.92 atm), 10 °C (283K) and 350 L:

[tex]n=\frac{PV}{RT}=\frac{1.92atm*350L}{0.082\frac{atm*L}{mol*K}*283K}\\ \\n=29.03molAir[/tex]

Next, since the molar mass of air is 28.97 g/mol, the mass is computed to be:

[tex]m=29.03mol*\frac{28.97g}{1mol} \\\\m=840.88g[/tex]

Best regards.

A. The measured pH of a 0.100 M HCl solution at 25 degrees Celsius is 1.092. From this information, calculate the activity coefficient of H+.B. The measured pH of a solution of 0.010 HCl and 0.090 KCl at 25 degree Celsius is 2.102. Calculate the activity coefficient of H+ in this solution.C. Why does the pH change in part B relative to that in part A?

Answers

Answer:

activity coefficient [tex]\mathbf{\gamma =0.809}[/tex]

activity coefficient [tex]\mathbf{\gamma = 0.791}[/tex]

The change in pH in part A = 0.092

The change in pH in part B =  0.102

Explanation:

From the given information:

pH of HCl solution = 1.092

Activity of the pH solution [a] = [tex]10^{-1.092}[/tex]

[a] = 0.0809 M

Recall that [a] = [tex]\gamma[/tex] × C

where;

[tex]\gamma[/tex]  = activity coefficient

C = concentration

Making the activity coefficient the subject of the formula, we have:

[tex]\gamma = \dfrac{[a]}{C}[/tex]

[tex]\gamma = \dfrac{0.0809 \ M}{0.100 \ M}[/tex]

[tex]\mathbf{\gamma =0.809}[/tex]

B.

The pH of a solution of HCl and KCl = 2.102

[a] = [tex]10^{-2.102}[/tex]

[a] = 0.00791 M

activity coefficient [tex]\gamma = \dfrac{0.00791 \ M}{0.01 \ M}[/tex]

[tex]\mathbf{\gamma = 0.791}[/tex]

C. The change in pH in part A = 1.091 - 1.0 = 0.092

The change in pH in part B = 2.102 -2.00 = 0.102

What are the boiling points and freezing points (in oC)of a solution of 50.3 g of I2in 350 g of chloroform? The kb= 3.63 oC/m, the kf= 4.70 oC/m for CHCl3, and the molar mass of I2is 253.8 g/mol. The normal boiling point for CHCl3is 61.2 oC, and the normal freezing point for CHCl3is -63.5 oC.

Answers

Answer:

F.p   ≈  - 66.16⁰c

B.p  ≈ 59.1⁰c

Explanation:

Normal boiling point = 61.2⁰c

Normal freezing point = -63.5⁰c

Kb = 3.63⁰⁰ c/m

Kf = 4.70⁰ c/m

molar mass = 253.8 g/mol

solvent = 350 g = 0.35 kg

calculate The new freezing point and Boiling point

First we have to find the molality = number of moles / solvent in kg

= 0.198 / 0.35 = 0.5657 M

Hence the new freezing point can be calculated as

Normal freezing temp -  new freezing temp = Kf * molality

= -63.5 - F.p = 4.7 * 0.5657

F.p = -63.5 - 2.6588 ≈  - 66.16⁰c

Boiling point

Normal boiling point - new boiling point = Kb * molality

= 61.2 - B.p = 3.63 * 0.5657

B.p = 61.2 - 2.0535 ≈ 59.1⁰c

What do metaloids share with nonmetals?

Answers

Answer:

Most metalloids have some physical properties of metals and some physical properties of nonmetals. They fall between metals and nonmetals in their ability to conduct heat and electricity. They are shiny like metals but brittle like nonmetals.

Explanation:

which alkene represents the correct starting material phg?

Answers

Explanation:

The pH is larger than 7.

The relationship between pH and pOH is

pH + pOH = 14

if something is base, it's pH is greater than 7.

it's pOH is between 0 and 7.

a race car at the Daytona 500 zips around the track .its travel the first 80 kilometers in 0.4 hours. the next 114 kilometers take 0.6 . the following 80 kilometers take 0.4 hours to calculate the race car average speed.

Answers

The answer to this should be around 40

A race car at the Daytona 500 zips around the track its travel the first 80 km in 0.4 hours, the next 114km take 0.6, the following 80 km take 0.4, so the average speed is 195.71 km/hr.

How do we calculate the average speed?

Average speed of any body will be calculated by dividing the total time to cover the ditance from the total distance covered.

Total distance to cover = 80km + 114km + 80km = 274km

Total time to cover distance = 0.4hr + 0.6hr + 0.4hr = 1.4hr

Average speed of car = 274/1.4 = 195.71 km/hr

So, the average speed of car is 195.71km/hr

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List the types of electromagnetic radiation in order of increasing frequency.

Answers

Answer:

In order of increasing frequency and decreasing wavelength these are: radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays........... ᕕ( ᐛ )ᕗ

..

Identify the reagents

Answers

It’s the 3rd one :)
Hope this helped

3-An analysis that determines the relative amounts of analytes in numerical terms
A) Quantitative Analysis
B) Qualitative Analysis
C)Quantitative Synthesis
D) Qualitative Synthesis
Q1-(30 Marks) Choose the correct answer​

Answers

Answer:

A.

Explanation:

Quantitative analysis.


List all the different ways we can use a model to represent things

Answers

Modeling for chemistry is periodic table of elements during high school

The density of an element is 11.3 g/cm'. What is its density in kg/mº? ​

Answers

Answer:

11.3 g/cm³ = 11.3x100x100x100/ 1000 = 11300kg/m³

Explanation:

You have an atom with a mass number of 100 with 85 neutrons. What is this
element?

Answers

Answer:

phosphorus i believe

Explanation:

in order to find the atomic number you minus the mass number from number of neutrons then just look it up in a periodic table

The mass number of the atom is 100 and number of neutrons is 85. Then, number of protons is 15. Then, element with 15 protons and 15 electrons is phosphorous.

What is mass number ?

An atom is composed of subatomic particles electrons, protons and neutrons. Protons and neutrons are located inside the nucleus. The mass number of an atom is sum of number of protons and neutrons.

The number of electrons in an atom in its neutral state is called its atomic number. In a neutral atom, the number of electrons and proton are the same.

Give the mass number = 100

no.of neutrons = 85

no.of protons = 100 -85 =15

no.of electron = 15

Thus, atomic number = 15.

The element with atomic number of 15 is phosphorous (P).

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Which lists the waves in order of frequency, from highest to lowest?
O X-rays, gamma rays ultraviolet
O radio waves, visible light, X-rays
O ultraviolet, microwaves, gamma rays
O visible light, infrared, microwaves

Answers

Visible light, infrared, microwaves. This is the waves in order of frequency, from highest to lowest. Therefore, the correct option is option D.

What is electromagnetic wave?

One of the various ways that energy moves through space is electromagnetic radiation. Electromagnetic radiation includes the heat from a blazing fire, the sun's light, the X-rays your doctor uses, and the energy used it to cook food inside a microwave. Although though these energies may appear to be very different from each other, they are connected by the fact that they all have characteristics of waves.

The amplitude of a wave is the vertical line between both the tip of the crest and the wave's axis. This is the characteristic linked to the wave's brightness or intensity. The wavelength of a wave is the horizontal separation of two succeeding crests or troughs. Visible light, infrared, microwaves. This is the waves in order of frequency, from highest to lowest.

Therefore, the correct option is option D.

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Which of the following is an example of a chemical change
A. apple slices turn brown
B. toast burns
C. silver tarnishes
D. all of these are chernical changes​

Answers

Answer:

D. all of these are chemical changes

A 500 gram piece of metal had a volume of 2.75cm3. What is it’s density

Answers

Answer:

181.82 g/cm3

Explanation:

density is mass / volume so it is 500 / 2.75=181.82 g/cm3

3. The 2 in 1s2 represents the number of
located in that energy level.
Answers:
electrons
protons

Answers

Answer:

electrons

Explanation:

In an atom, you can have varying numbers of electrons, depending on if its an ion or not.  You can use the orbitals to see the energy level of the atom.

An atom has only one number of protons.  The number of protons cannot vary.

The graph below shows the speed of a downhill
skier during a period of several seconds. Use the
graph to answer Question 13.
16
12
Speed (m/s)
8
0
1
3
3
2
Time (s)
13. Read Graphs What is the skier's acceleration?

Answers

Answer:

16

Explanation:

Lead (Pb) (average atomic mass 207.19 amu) has three naturally-occurring isotopes, Pb206, Pb207and Pb208 with isotopic masses of 205.98 amu, 206.98 amu and 207.98 amu respectively. If the isotopes Pb207and Pb208 are present in equal amounts, calculate the percent abundance of each isotope of Pb, which are, Pb206, Pb207 and Pb208.​

Answers

Answer:

pb am 207.19 amu

pb206, pb207and pb208

(7.31 x 10+4 g) + (3.2300 x 10+3 g) =

Calculator answer

Final answer

Answers

7g + 105.4

this is the question simplified correctly

If the chemical reaction AB + CD ⟶ AD + BC releases heat, what is true of the stored bond energy of the reactants and products? The bonds do not have energy, the atoms release heat. The bond energy of the reactants is the same as the bond energy of the products. The bond energy of the reactants is lower than the bond energy of the products. The bond energy of the reactants is higher than the bond energy of the products.

Answers

Answer:

The correct option is the last option

Explanation:

The chemical reaction provided in the question is a double-displacement reaction which is an exothermic reaction (which is the reason for the release of heat). An example of a double displacement reaction and exothermic reaction is the neutralization reaction illustrated below.

HCl + NaOH ⇒ NaCl + H₂O

From the law of conservation of energy, energy can neither be created nor destroyed, hence the total energy in a given system should ordinarily be the same (in the reactants and products), however when energy is released in a reaction (as in the case with an exothermic reaction), it shows there are more bond energy in the reactants than in the products and it is the excess energy that is been released into the atmosphere.

Which statement best describes chemical properties of matter? Chemical properties, such as density, must be observed when a substance is in its natural state at room temperature and normal atmospheric pressure. Chemical properties, such as reactivity, must be observed when a substance is in its natural state at room temperature and normal atmospheric pressure. Chemical properties, such as combustibility, are generally observed as the identity of a substance changes and one or more new substances form. Chemical properties, such as boiling point, are generally observed as the identity of a substance changes and one or more new substances form.

Answers

Answer:

Chemical properties, such as combustibility, are generally observed as the identity of a substance changes and one or more new substances form.

Explanation:

Chemical properties, such as combustibility, are generally observed as the identity of a substance changes and one or more new substances form. Hence, option C is correct.

What are the chemical properties of matter?

Chemical properties are properties that can be measured or observed only when matter undergoes a change to become an entirely different kind of matter.

Substances made of wood, such as paper and cardboard, are also flammable.

Chemical properties are properties that can be measured or observed only when matter undergoes a change to become an entirely different kind of matter.

They include reactivity, flammability, and the ability to rust.

Hence, option C is correct.

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Calculate the atomic mass of element "X" if it has 2 naturally occurring isotopes with the following masses and natural abundances. X−107 106.90509 amu 51.84%X−109 108.90476 amu 48.46%

Answers

Answer:

Using my (not very precise) periodic table, I get the mass of Ag as 107.87

Explanation:

This must be a combination of these two isotopes. So the % of the other isotope must be 48.16%.

To work with these percentages in an equation I'll use them as decimals.

So now I can start putting them into an equation:

107.87  =  ( 106.905 ⋅ 0.5184 )  +  ( x ⋅ 0.4816 )  

Because both of the isotope masses, multiplied by their percentage, would give us the overall average mass.

107.87  =  55.419552  ⋅  (  x  ⋅  0.4816 )  

Worked out the brackets that we can work out, and then rearrange to give:

107.87  −  55.419552  =  (  x  ⋅  0.4816  )

Again rearrange:

52.450448 =  (  x  ⋅  0.4816  )  

And final rearranging:

x  =  52.450448  - 0.4816

x

=

108.909

(using same sig figs as given in question)

You probably want to work through that again using your periodic table value for Ag.

what's evaporation according to kinetic particle theory?​

Answers

Answer:

Evaporation is a change of phase from liquid to gas explained as follows : When particles in the liquid phase are heated, they gain kinetic energy and move faster and further apart.

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When a piece of paper is held with one face perpendicular to a uniform electric field the flux through it is 25 N .m2 /C. When the paper is turned 25 with respect to the field the flux through it is:_____.1. 02. 12 N .m2 /C3. 21 N .m2 /C4. 23 N .m2 /C5. 25 N .m2 /CB. A charged point particle is placed at the center of a spherical Gaussian surface. The electric flux is changed if:______.1. the sphere is replaced by a cube of the same volume2. the sphere is replaced by a cube of one-tenth the volume3. the point charge is moved off center (but still inside the original sphere)4. the point charge is moved to just outside the sphere5. a second point charge is placed just outside the sphereC. A charge of 0.8 109 C is placed at the center of a cube that measures 5 m along each edge. What is the electric flux through any 2 faces of the cube? grade 7. i actually already learnt this but this whole quarantine thing made me forget lolz. what are factors?example : is 3 a factor of 372?please answer and explain Suppose a necklace is made from 18-karat gold and weighs 54 grams. Find the weight, in grams, of the pure gold in the necklace. When using the power rule, the original coefficient:__________a) Is multiplied by the original exponent.b) Only changes if the function is in terms of x.c) Is ignored Which best explains how photosynthesis is helpful to humans? It reduces the amount of harmful rays released by the sun. It increases the levels of carbon dioxide in the air. It provides oxygen for humans to breathe. It produces proteins, which humans can eat. Complete the autoionization reaction for water.H2O + H2O Which lead could you use to grab a readers attention in an article about blackwater falls? The typical starting point of any firm's marketing mix is the:____________A) analysis of what production equipment is available and owned by the companyB) design of the promotion campaign to be used for the productC) selection of the places through which the good or service will be soldD) determination of the product's price, enabling future revenues and budgets to be estimatedE) development of the good or service to be sold Simplify.-(1 - 3)2 - 2x2 Identify the part of speech of the italicized word in each sentence. Sheilas mother can drive us to the mall.(artical/pronoun/preposition) That song is stuck in my head.(Article/Pronoun/Preposition) The teacher handed the math test back today.(Article/Pronoun/Preposition) The elemental analysis of an organic solid extracted from gum arabic showed that it contained 40.0% C, 6.7% H, and 53.3% O. A solution of 0.650 g of the solid in 27.8 g of the solvent diphenyl gave a freezing point depression of 1.56 C. Calculate the molar mass and determine the molecular formula of the solid (kf for diphenyl is 8.00 C/m). To earn full credit, clearly show your work with units and proper significant figures Known as feudalism. was a loosely organized system of rule in whichpowerful local lords divided their landholdings among lesser lords. In exchange,these lesser lords, orpledged service and loyalty to the greater lord. Can someone please explain to me how I solve a problem like this? I'm learning about proving parallel Lines right now. Thank you! Two samples were taken of fish caught on Small Lake and are shown in the table below. It is estimated that the Small Lake fish population is roughly 1,000 fish. What is the average number of brown trout in the lake? Small Lake Fish Sample 15 Sample 1 Rainbow Trout Brown Trout Largemouth Bass 11 Sample 2 Rainbow Trout Brown Trout Largemouth Bass 3 1 9 11 43 80 160 333. the sum of 3 consecutive integers is -69. Find the largest What is the value of 9+21(13+5)? A.287 B.395 C.387 D.540 Discuss the author's use of phrases and clauses. Begin by identifying the prepositional phrases and any noun, adjective, and adverbial clauses. I need help on this question 1 1/4 times 2/5 divided by 3 1/3 Which point represents the value of -(-2) on the number line?Point APoint BPoint CPoint D