1. How many joules of heat are necessary to melt 500 g of ice at its freezing point?

Please show work!

Answers

Answer 1

Answer:

40 kcal

Explanation:

Heat required to melt

1 g

of ice at

0°C

is approximately

80 cal

. This is also called latent heat of fusion of ice.

For

500 g

of ice

Q

=

500

g

×

80

cal

g

=

40000 cal = 40 kcal


Related Questions

Determine whether aqueous solutions of the following salts are acidic, basic, or neutral: (a) Al(NO3)3 (b) RbI (c) KHCO2 (d) CH3NH3Br

Answers

The aqueous solution and their respective properties include the following:

Al(NO3)3 - acidicRbI - neutralKHCO2 - basic CH3NH3Br - acidic

What is pH?

This is defined as the degree of acidity or alkalinity of a substance and pH from 1.0 - 6.9 is acidic, 7 is neutral while 7.1 - 14.0 is basic.

The aqueous solutions and their appropriate pH can be seen above which is the right choice.

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Procedure for Lab: Enthalpy ?

I have a lab on Edge that's about Enthalpy. The assignment is called " Lab: Enthalpy". If someone could help me with the procedure of the lab, that would be nice. (I don't need the data table, just the procedure.)

Answers

The enthalpy refers to the thermodynamic characteristics that have chemical systems associated with their internal energy.

What is enthalpy?

The enthalpy refers to the thermodynamic features of the chemical systems associated with the energy of such systems.

Enthalpy is used to estimate the ability of the system to perform work and release energy in the form of heat.

It is well known that different types of chemical reactions may exhibit different enthalpies, which can be estimated by the internal energy, pressure of the system and volume.

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Answer:

Here you are <3

Explanation:

I attached the one I just submitted

Determine the difference between archaea and bacteria. (1 point)

All bacteria are unicellular organisms, while some archaea are multicellular.


Archaea live in extreme environments, while bacteria can be found in most places on Earth.

Bacteria and archaea have different shapes.


Archaea is the domain of life that includes the plant and animal kingdoms, while the bacteria domain includes fungi and protists.

Answers

Answer:

I have this work and I'm in 5th grade

Explanation:

Answer:

Archaea live in extreme environments, while bacteria can be found in most places on Earth.

Explanation:

Doing a the test now and this is the answer.

What volume of .15M NaOH could be produced with only 5 grams of NaOH and water?

Answers

The volume of 0.15M NaOH that could be produced with only 5 grams of NaOH and water is 0.83L.

How to calculate volume?

The volume of a substance can be calculated using the following expression:

Molarity = number of moles ÷ volume

The number of moles of NaOH can be calculated by dividing the mass of NaOH by its molar mass.

Molar mass of NaOH = 40g/mol

n = 5/40

n = 0.125moles

Volume of NaOH = 0.125mol ÷ 0.15M

Volume = 0.83L

Therefore, the volume of 0.15M NaOH that could be produced with only 5 grams of NaOH and water is 0.83L.

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A reaction rate increases by a factor of 655 in the presence of a catalyst at 37°C. The activation energy of the original pathway is 106 kJ/mol. What is the activation energy of the new pathway, all other factors being equal? Group of answer choices 89.3 kJ/mol 16,600 kJ/mol 89.3 J/mol 16,600 J/mol

Answers

For a reaction rate that increases by a factor of 655 in the presence of a catalyst at 37°C, the activation energy of the new pathway  is mathematically given as

Ea2=89.28JKoule/mol

What is the activation energy of the new pathway, all other factors being equal?

Generally, the equation for the rate constant  is mathematically given as

K=Ae^{Ea1/Rt}

Therefore

[tex]\frac{1}{655}=\frac{1}{8.31*3.10}(Ea2-105000)[/tex]

Ea2=89286.083Joule/mol

In conclusion, the activation energy

Ea2=89.28JKoule/mol

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what is the volume of
NH4 NO3(s) — N2O(g) + 2H2O(g)

Answers

Answer:

Explanation:

NH4NO3(s) N2O(g) + 2H2O(g) What is the total volume of gases produced at 546 K and 1.00 atm pressure when 240 g of ammonium nitrate undergoes the above decomposition reaction? A) 9 × 22.4 L B) 3 × 22.4 L C) 12 × 22.4 L D) 18 × 22.4 L E) 6 × 22.4 L

1) A solution is prepared with 0.55 M HNO2 and 0.75 M KNO2. Fill in the ICE Table with the appropriate values

2) The Ka for this solution of HNO2 is 6.8x10^-4. Based on the ICE table, set up the expression for Ka.

3) Based on your ICE table, determine the pH of the buffer solution

Answers

Based on the calculations through the ICE table, the pH of the buffer solution is equal to 3.30.

Given the following data:

Concentration of [tex]HNO_2[/tex] = 0.55 M.Concentration of [tex]KNO_2[/tex] = 0.75 M.Rate constant = [tex]6.8 \times 10^{-4}[/tex]

How to determine the pH of the buffer solution.

First of all, we would write the properly balanced chemical equation for this chemical reaction:

                                     [tex]HNO_2(aq)\rightleftharpoons H^{2+} (aq)+ KNO_2^{-}(aq)[/tex]

Initial cond.                       0.55M              0          0.75M

    [tex]\Delta C[/tex]                                   -x                   x               x

At equib.                           0.55M - x         0 + x      0.75M + x

From the ICE table, the Ka for this chemical reaction is given by:

[tex]K_{a}=\frac{[H^+][NO_2^+]}{HNO_2} \\\\H^+ = K_{a}\frac{[HNO_2]}{[NO_2^+]} \\\\H^+ = 6.8 \times 10^{-4} \times \frac{0.55}{0.75} \\\\H^+ = 6.8 \times 10^{-4} \times 0.733\\\\H^+ = 4.98 \times 10^{-4} \;M[/tex]

Now, we can calculate the pH of the buffer solution:

[tex]pH=-log[H^+]\\\\pH=-log[4.98 \times 10^{-4}]\\\\pH=-(-3.30)[/tex]

pH = 3.30.

Alternatively, you can calculate the pH of this buffer solution by applying Henderson-Hasselbalch equation:

[tex]pH =pka+ log_{10} \frac{A^-}{HA}[/tex]

Where:

HA is acetic acid.[tex]A^-[/tex]  is acetate ion.

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As a chemical energy is converted into heat energy during a reaction the total energy of the system

Answers

When a chemical energy is converted to hear during a chemical reaction, the total energy of the system remain constant.

Law of conservation of Energy?

Law of conservation of energy state that the today energy interacting with bodies in a isolated system remain constant

the Law of Conservation state that the total energy in a system remain unchanged, and that oftentimes a chemical reaction will absorb or release energy in the form of heat, light, or both.

Therefore, The total energy of the system remain constant.

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Calculate the % by mass concentration for each of the following solutions. Match the answers.
1.25g NaCl in 100.0g of solution = [a]%
ce
2.50g K2Cr2O7 in 96.0g of solution = [b]%
nts
10.0g CaCl2 in 250.0g of solution = [c]%
ns
20.0g Kl in 100.Ogof solution = [d]%


Answers

The percentage by mass of each of the compounds would be 40%, 2.6%, 4%, and 20% respectively

Percentage by mass

The percentage by mass of a substance is given by:

Percent by mass = mass of substance/mass of solution x 100%.

For NaCl: Percent by mass = 25/100 = 40%For K2Cr2O7: Percent by mass = 2.50/96 = 2.6%For CaCl2: Percentage by mass = 10/250 = 4%For KI: Percent by mass = 20/100 = 20%

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How many moles of carbon are present in 1.50mole of aspirin , C_{9}*H_{8} * O_{4}

Answers

Given the molecular formula of aspirin, C₉H₈O₄, in 1.50 moles of aspirin there are 13.5 moles of carbon.

What is a mole?

The mole is the SI base unit for the amount of matter. 1 mole of particles contains a number of Avogadro's particles.

We have 1.50 moles of aspirin, C₉H₈O₄. According to the molecular formula, the molar ratio of C₉H₈O₄ to C is 1:9.

1.50 mol C₉H₈O₄ × (9 mol C/1 mol C₉H₈O₄) = 13.5 mol C

Given the molecular formula of aspirin, C₉H₈O₄, in 1.50 moles of aspirin there are 13.5 moles of carbon.

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Which of the following represents the velocity of a moving object?
Select one:

40 m north.

40.

40 m/s north.

40 m/s.

Answers

Answer:

The correct answer would be 40 m/s

Explanation:

The reason 40 m/s is the correct answer is because m/s stands for meters per second.

Hope this helps you with what you're working on! :D

Answer:

40 m/s north

Explanation:

Velocity is a vector quantity, so it have both direction and magnitude.

why is it necessary to standardize a secondary standard before use?

Answers

Answer:

As the name implies, a secondary standard is used by standard laboratories, which include companies involved in the preparation of reagents and kits, as well as laboratories responsible to produce quality control material for use by other laboratories. They use the primary standard as the primary calibrator or primary reference material, and they calibrate their instruments against it. Smaller labs use secondary standards to calibrate control material for analysis of unknown concentrations. For smaller labs, secondary standard serves as an external quality control. As a result, it is essential that the secondary standard be standardized against the primary standard before it can be applied.

I hope this helps you

:)

What type of molecule is cis-2-pentene?
O A. Alkane
B. Alkyne
C. Branched alkane
D. Alkene

Answers

The given molecule, cis-2-pentene, is an Alkene. The correct option is D. Alkene

Saturated & Unsaturated Hydrocarbons

Alkanes, Alkenes, and Alkynes are examples of simple hydrocarbons.

Alkanes are the simplest organic compounds. They have only single bonds between carbon atoms and are called saturated hydrocarbons. Their nomenclature usually ends in -ane.

Alkenes on the other hand have at least one carbon-carbon double bond. Their nomenclature usually ends in -ene.

Alkynes have one or more carbon-carbon triple bonds.Their nomenclature usually ends in -yne. Alkenes and alkynes are called as unsaturated hydrocarbons.

The given molecule is cis-2-pentene

Since the name of the molecule ends in "ene", the molecule is an Alkene.

Hence, the given molecule, cis-2-pentene, is an Alkene. The correct option is D. Alkene

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Answer: Alkene

Explanation: just took tha test

298K is equivalent to how many degrees Celsius?
Explain the steps

Answers

Answer:

24.80°C

Explanation:

hope it helps...!!!

How do i solve this?

Draw the product of this reaction. Ignore inorganic byproducts.​

Answers

The compound is formed by addition reaction. The product is showed in the image attached.

Addition reaction

The term addition reaction refers to a type of reaction in which a compound is added across the multiple bond. In this case, the iodine molecule is added to the olefinic bond as shown.

The structure of the product formed has been attached to this answer. The product is formed by addition across the double bond.

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What temperature creates hail

Answers

Answer:

32 °F

Formation. Hail forms in strong thunderstorm clouds, particularly those with intense updrafts, high liquid water content, great vertical extent, large water droplets, and where a good portion of the cloud layer is below freezing 0 °C (32 °F).

Explanation:

brainlist me and that's all I know and we have the same module I guess

What is molarity of 47.0 g KCl dissolved in enough water to give 375 mL of solution?

Answers

This question provides us –

Weight of [tex] \bf KCl [/tex] is = 47 gVolume, V = 375 mL

__________________________________________

Molar Mass of [tex]\bf KCl [/tex] –

[tex]\qquad[/tex] [tex]\twoheadrightarrow\bf 39.0983 \times 35.453 [/tex]

[tex]\qquad[/tex] [tex]\twoheadrightarrow\bf 74.5513[/tex]

Using formula

[tex]\qquad[/tex] [tex]\purple{\twoheadrightarrow\bf Molarity _{(Solution)} = \dfrac{ W\times 1000}{MV}}[/tex]

[tex]\qquad[/tex] [tex]\twoheadrightarrow\bf Molarity _{(Solution)} = \dfrac{ 47 \times 1000}{74.5513\times 375}[/tex]

[tex]\qquad[/tex] [tex]\twoheadrightarrow\bf Molarity _{(Solution)} = \dfrac{47000}{27956.7375}[/tex]

[tex]\qquad[/tex] [tex]\twoheadrightarrow\bf Molarity _{(Solution)} = \cancel{\dfrac{47000}{27956.7375}}[/tex]

[tex]\qquad[/tex] [tex] \twoheadrightarrow\bf Molarity _{(Solution)} = 1.68117M [/tex]

[tex]\qquad[/tex] [tex]\pink{\twoheadrightarrow\bf Molarity _{(Solution)} = 1.7M} [/tex]

Henceforth, Molarity of the solution is = 1.7M

___________________________________________

if you add 3 mL of water to 1 ml of nadh mix and get an observance of 0.2 what is the concentration of the original nadh solution

Answers

Answer:

you are looking at the official nkana fc website

At 4.5 atm of pressure, the solubility of a gas is 9.5 g/L.
How much gas, in grams, will dissolve in 1 L if the pres.
sure is reduced by 3.5 atm?

Answers

For a gas at 4.5 atm of pressure, the solubility of a gas is 9.5 g/L.

How much gas, in grams, is mathematically given as

s2=8.3782grams

What is the amount of gas in grams?

Generally, the equation for the   is mathematically given as

Si /S2 √P1/√P2

Therefore

[tex]s2=9.5*\sqrt{3.5}/\sqrt{4.5}[/tex]

s2=8.3782g

In conclusion. The solubility is

s2=8.3782g

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How many kJ of heat do you need to raise the temperature of 200 g of Aluminum from 80 °C to 100 °C?

Remember to convert your answer to kJ. Round your answer to two decimal places.

Answers

Answer:

0.01

Explanation:

100 -80=20

200/20=10/1000=0.01kj

What are valence electrons?

A electrons in the outermost level of each atom
B electrons found in the s or p orbitals of atoms
C electrons in the innermost level of each atom
D electrons produced by the radioactive decay of the nucleus of an atom

Answers

A electrons in the outermost level of each atom

According to the given equation, how many moles of O, are required to react with 4.71 moles of C4H10?
2C4H10 + 1302 —8CO2 + 10 H

Answers

According to the given equation, 2C4H10 + 1302 — 8CO2 + 10H, 2 moles of O are required to react with 4.71 moles of C4H10.

How to calculate number of moles?

The number of moles of a compound can be calculated stoichiometrically as follows:

The balanced chemical equation is given as follows:

2C4H10 + 1302 — 8CO2 + 10H

Based on the above equation, 2 moles of C4H10 reacts with 13 moles of O

Therefore; 4.71 moles of C4H10 will react with 4.71 × 6.5 = 30.62 moles of O

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Answer: 30.6

Explanation:

In cells, __________ are proteins that are needed to lower the amount of energy required to start chemical reactions

Answers

Answer: I think it’s enzymes

Explanation:

Find the acceleration of the 2 kg block in the following diagram. ( Hint find the net force!)​

Answers

Answer:
2m/s^2
Explanation:
Fnet = F2-F1
ma = 8-4
2a = 4
Dividing both sides by 2
a = 2
Therefore (a) thus acceleration is 2m/s^2

The acceleration of the block will be -2 m/s² in the backward direction.

What is force?

Force is defined as the product of mass of the body and the acceleration with which it is moving. Mathematically -

F = ma

It is a vector quantity. In the three dimensional coordinate system, the force vector can be resolved as -

[F] = F[x] a[x] + F[y] a[y] + F[z] a[z]

Given is a diagram in which two forces are acting on a block.

We can write -

Force 1 on block [F1] = 4 a[x]

Force 2 on block [F2] = 8 (- a[x]) = - 8 a[x]

Resultant of forces [F] = [F1] + [F2] = 4 a[x] + ( - 8 a[x]) = - 4 a[x]

Now, we know that -

F = MA

A = F/M

In vector form, acceleration will be -

[A] = - 1/m × (4 a[x])

[A] = -1/2 × (4 a[x])

[A] = - 2 a[x]

Therefore, the acceleration of the block will be -2 m/s² in the backward direction.

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what is safe storage of produced materials​

Answers

Answer:

Stacking bags and bundles.

Explanation:

Interlock them in rows to ensure they're secure.

Answer:

Material Storage Facilities means an uncovered area used on a permanent basis for outside

Explanation:

Material Storage Facilities means an uncovered area where bulk materials (liquid, solid, granular, etc.) are stored in piles, barrels, tanks, bins, crates, or other means.

Additional Benchmarks for Federal, State, or Municipal Facilities with Incidental Solid De-Icing Material Storage Facilities monitoring under the requirements of subparagraph (D)(ii) above shall not be subject to Benchmark requirements for Chloride or Cyanide.

Directors are fully briefed on all business related matters, risk assessment and new initiatives proposed by the Company.

How can you use a barium chloride solution to help identify a sulfate solution?

Answers

answer explanation:

Sulfate ions in solution, SO 4 2 -, are detected using barium chloride solution. The test solution is acidified using a few drops of dilute hydrochloric acid, and then a few drops of barium chloride solution are added. A white precipitate of barium sulfate forms if sulfate ions are present.

Answer:

Testing for sulfate ions

Sulfate ions in solution, SO 4 2 -, are detected using barium chloride solution. The test solution is acidified using a few drops of dilute hydrochloric acid, and then a few drops of barium chloride solution are added. A white precipitate of barium sulfate forms if sulfate ions are present.

Explanation:

What is The fmu (grams/mole) for disulfur hexachloride *the formula for it is S2Cl6*

Answers

Hexasulfur Dichloride

Name: Hexasulfur Dichloride

Formula: S2Cl6

Molar Mass:276.848

Example Reactions:

• S2Cl6 + 4H2O = 2SO2 + 6HCl + H2

What environmental change is shown in the image that might affect the survival of animals

A. Increased space
B. Increased predators
C. Lack of food
D. Pollution

Answers

Answer:

it thinks it pollution

Explanation:

hope that helps

Which pictures show the car at zero acceleration? A. Picture 1 only. B. Pictures 1 and 3. C. Picture 2 and 4. D. Picture 4 only.

Answers

Picture 1 shows choice B

Explanation:

picture 1 shows the car to which the net force is a zero

Amphetamine (C9H13N) is a weak base with a pKb of 4.2.

Calculate the pH of a solution containing an amphetamine concentration of 215 mg/L .
Express your answer to two decimal places.

Answers

Weak base: [OH⁻] = √Kb.C

pKb = 4.2

[tex]\tt Kb=10^{-4.2}[/tex]

c = concentration

MM Amphetamine (C9H13N) = 135.21 g/mol

c = 215 mg/L = (0.215 g : 135,21 g/mol) / L = 0.00159 mol/L = 1.59  x 10⁻³ mol/L

[tex]\tt [OH^-]=\sqrt{10^{-4.2}\times 1.59\times 10^{-3}}=3.17\times 10^{-4}[/tex]

pOH = 4 - log 3.17

pH = 14 - (4 - log 3.17)

pH = 10 + log 3.17 = 10.50

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