At room temperature (20 °C), milk turns sour in about 64 hours. In a refrigerator at 3 °C, milk can be stored three times as long before it sours.
(a) Estimate the activation energy of the reaction that causes the souring of milk.
(b) How long should it take milk to sour at 40 °C?

Answers

Answer 1

Answer: Since k2 corresponds to 64 hours, the time for the milk to sour at 40 C is 64 h / 9.38 = 6.8 hours.

Explanation:

At temperature T1, the Arrhenius Equation is:

k1 = Ae^(-Ea/RT1).

An equivalent equation can be written at T2:

k2 = Ae^(-Ea/RT2).

If these equations are divided, then A cancels:

k1/k2 = e^(-Ea/RT1)/e^(-Ea/RT2)

Taking the natural log:

ln(k1/k2) = (Ea/RT2)-(Ea/RT1);

or:

ln(k1/k2) = (Ea/R)(1/T2 - 1/T1)

We can infer from the question that the milk sours 3 times as fast at the higher temperature (let's call it T1), so we can arbitrarily call k2 = 1 and k1 = 3.

a) Substitute:

ln(3) =  (Ea/R)(1/276.15 K - 1/293.15 K).

We get Ea/R = 5231.6. Multiply this by whatever value of R you choose to get Ea in your favorite energy unit. Remember the sig figs.

b) Again, let's let the lower temperature = T2, since we have defined k2 = 1:

ln(k1) = (5231.6)(1/276.15 K - 1/313.15);

ln(k1) = 2.24, so k1 = 9.38.

Since k2 corresponds to 64 hours, the time for the milk to sour at 40 C is 64 h / 9.38 = 6.8 hours.


Related Questions

Which pair of elements will form a covalent bond? A. Aluminium and Chlorine B. Carbon and Sulfur C. Lithium and Oxygen D. Potassium and Chlorine

Answers

Explanation:

Aluminum and chlorine form covalent bond.

Therefore,

Option A is correct✔

Please help will give brainliest

Answers

Answer:

the answer id D

Explanation:

i dont know im just living here 5

Complete the statement of equality.

Answers

Answer:

This is not a viable question.

Explanation:

HELPPPPPPP

is this chemical or physical reaction

Answers

Answer:

Chemical reaction

Explanation:

It's creating a whole other substance

Which three are advantages of asexual reproduction?

A:Offspring are more likely to survive environmental changes.

B:Some offspring are more likely to survive a disease.

C:Less energy is required to reproduce.

D:The population can increase from only one parent.

E:The population can increase quickly.

Answers

Answer:

sorry if I get this wrong I think it is C

Explanation:

C, D, and E

A and B cannot be true because asexual reproduction means the parent organism is essentially creating clones of itself, providing no variation in DNA and making all offspring vulnerable to the same environmental changes and diseases as the parent.

which 2 not one 2! hjmdnxhjund

Answers

Answer:

A and D then I guess

Explanation:

sorry hope this helps!


The percent ionization of a 0.350 M HC,H,O2 solution. Ka(HC2H302)​

Answers

Answer:

The answer is 56

Explanation:

i need points

which group or groups of atoms are the only atoms with f orbitals?

Answers

Answer:

Lanthanides and Actinides

Explanation:


PLEASEEE HELP ?!?!?!

which of the following processes provide evidence of the particulate nature of matter
I. Diffusion
II. Filtration
III. Osmosis

A. I and II only
B. I and III only
C. II and III only
D. I, II and III​

Answers

Answer:

B

Explanation:

I think the answer is Diffusion and Osmosis

The processes that provide evidence of the particulate nature of matter would be diffusion and osmosis.

Matter is defined as anything with mass/weight and able to occupy space. Matters could be molecules of solid, liquid, or gases. The molecules of each category of matter have their specific characteristics.

Molecules of liquids and gases are able to diffuse. Diffusion is defined as the movement of molecules from the region of high concentration to the region of low concentration.

Molecules of solids in the dissolved form are also able to diffuse. Water molecules are also able to move from the region of high to the region of low water potentials by osmosis in the presence of a semi-permeable membrane.

Thus, both diffusion and osmosis back up the particulate nature of matter.

More on the particulate nature of matter can be found here: https://brainly.com/question/15230454?referrer=searchResults

velocity is a ______ quantity​

Answers

Answer:

vector quantity

Explanation: Brainliest pls

Please help Fast i dont Know

Answers

the answer should be B the rate at which work is accomplished

which of the following could be classified as producing a physical change?

Answers

A physical change involves a change in physical properties. Examples of physical properties include melting, transition to a gas, change of strength, change of durability, changes to crystal form, textural change, shape, size, color, volume and density.
Physical changes alter only the size, shape, form or matter state of a material. Water boiling, melting ice, tearing paper, freezing water and crushing a can are all examples of physical changes. On the other hand, chemical changes are a bit different. In a chemical change, a new substance is formed.

Scientists use _____ as chemical symbols.

dots
letters
shapes
lines

Answers

Answer:

Letters

Explanation:

Answer:

Letters

Explanation:

Chemical symbols are used to standardize the 'language of chemistry' and to identify elements and atoms in a chemical formula easily. Chemical symbols consist of one or two letters, most often derived from the name of the element.

A biochemist carefully measures the molarity of magnesium ion in of cell growth medium to be . Unfortunately, a careless graduate student forgets to cover the container of growth medium and a substantial amount of the solvent evaporates. The volume of the cell growth medium falls to . Calculate the new molarity of magnesium ion in the cell growth medium. Be sure your answer has the correct number of significant digits.

Answers

Answer:

760 uM

Explanation:

A biochemist carefully measures the molarity of magnesium ion in 47, mL of cell growth medium to be 97 uM. Unfortunately, a careless graduate student forgets to cover the container of growth medium and a substantial amount of the solvent evaporates. The volume of the cell growth medium falls to 6.0 mL. Calculate the new molarity of magnesium ion in the cell growth medium Be sure your answer has the correct number of significant digits.

The problem here is that the amount of magnesium ion remains the same irrespective of the volume.

Amount of magnesium in the growth medium = molarity x volume

    = 97 x [tex]10^{-6}[/tex] x 47 x [tex]10^{-3}[/tex] = 4.559 x [tex]10^{-6}[/tex]

Then, the volume reduced to 6.0 mL, the new molarity becomes;

molarity = mole/volume

       = 4.559 x [tex]10^{-6}[/tex]/6 x [tex]10^{-3}[/tex] = 7.598333 x [tex]10^{-4}[/tex] M = 759.83333 uM

To the correct number of significant digits = 760 uM

I am a nonmetal.I am in the Oxygen family and in row 3.I have 6 valence electrons.I am yellow and have a stinky smell.Who am i

Answers

Answer:

sulfur

Explanation:

In oxygen family sulfur has yellow color and also having stinky smell. Thus given statements are about sulfur.

It is present in oxygen family.

It has six valance electrons.

Its atomic number is 16.

Its atomic weight is 32 amu.

The electronic configuration of sulfur is given below,

S₁₆ = 1s² 2s² 2p⁶ 3s² 3p⁴

We can see the valance shell is third shell and it have six electrons thus sulfur have six valance electrons. (3s² 3p⁴ )

Sulfur is used in vulcanisation process.

It is used in bleach and also as a preservative for many food.

it is used to making gun powder.

Potassium Phthalate, KC8H604, is a main source of whistle fuel for many fireworks. A standard firework had 25g of potassium phthalate.​ Calculate the following:
The molar mass of the compound.
How many molecules of fuel there are
The number of moles of Carbon

Answers

Answer:

Explanation:

The given compound is:

           KC₈H₆O₄

Mass of the compound = 25g

Molar mass of the compound

KC₈H₆O₄

   Atomic mass of K  = 39

                             C  = 12

                             H = 1

                             O = 16

Molar mass of the compound  = 39 + 8(12) + 6 (1) + 4(16)

                                                   = 205g/mol

Number of molecules of fuel there in:

Find the number of moles then convert this to number of molecules;

    Number of moles  = [tex]\frac{mass}{molar mass}[/tex]  

    Number of moles  = [tex]\frac{25}{205}[/tex]   = 0.12mol

1 mole of a compound contains 6.02 x 10²³ molecules

 0.12 mole of the phthalate will contain 0.12 x 6.02 x 10²³ =

              7.34 x 10²²molecules

Number of moles of Carbon

  1 mole of the phthalate contains 8 mole of carbon

  0.12 mole of the phthalate will contain 0.12 x  8  = 0.96mole of carbon

Giselle is working with a chemical substance in a laboratory. She observes that when the chemical is heated, it gives off a gas. She assumes that the gas is oxygen but decides to test this assumption to verify it. Which type of scientific knowledge is Giselle’s assumption? A. fact B. hypothesis C. law D. observation E. theory

Answers

Answer:

The correct answer is B. Hypothesis

Explanation:

what is the kinetic energy of a 3kg ball that is rolling at 2 meters per second

Answers

Answer:

6 J

Explanation:

The kinetic energy of an object can be found by using the formula

[tex]k = \frac{1}{2} m {v}^{2} \\ [/tex]

m is the mass

v is the velocity

From the question we have

[tex]k = \frac{1}{2} \times 3 \times {2}^{2} \\ = \frac{1}{2} \times 3 \times 4 \\ = 3 \times 2[/tex]

We have the final answer as

6 J

Hope this helps you

Which of the following elements in a nonmetal? *
Zinc (Zn)
O Barium (Ba)
Krypton (Kr)
Lithium (Li)

Answers

Answer:

Krypton (Kr)

Explanation:

Nonmetals are the elements that have opposing features and characteristics of metals. Nonmetals do not shine and are dull in appearance. They are bad conductors of heat and electricity. They are brittle and cannot be beaten into sheets. The density, melting and boiling points of the nonmetals are low. Krypton (Kr) is a non metal whose atomic number is 36.

someone plz help me write notes (images attached)

Answers

Answer:

kya karna parega hume....???

Please answer it truthfully please​

Answers

Answer:

False

Explanation:

Chemical and Physical changes happen uniquely, they cannot happen at the same time. When you crumble a piece of paper you don't change its chemical form you change its physical form. When a piece of metal rusts its chemical composition changes, leading me to believe it is false.

Good luck on the rest of your assignment/test!


Atoms of the same element can have different properties. ( true or false )

Answers

Answer:

Atoms of the same element have the same chemical properties. The only differences between atoms of the same element are the number of neutrons in the nucleus and the atomic weight of each isotope. false

Answer:

False

Explanation:

Different elements can have different properties, but not atoms of the same element


What is electronegativity?
Explain the periodic trend -
what is it, why is it that way

Answers

Answer:

Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. The Pauling scale is the most commonly used. Fluorine (the most electronegative element) is assigned a value of 4.0, and values range down to caesium and francium which are the least electronegative at 0.7.

Explanation:

Major periodic trends include: electronegativity, ionization energy, electron affinity, atomic radius, melting point, and metallic character. ... These trends exist because of the similar atomic structure of the elements within their respective group families or periods, and because of the periodic nature of the elements

Robert makes a glass of tea and takes it outside with him. While outside, the thermal energy within the glass of tea is transferred to its surroundings. Based on this information, what else is happening within the glass of tea?
A.
The kinetic energy of the particles is increasing and the temperature is decreasing.
B.
The kinetic energy of the particles is increasing and the temperature is increasing.
C.
The kinetic energy of the particles is decreasing and the temperature is increasing.
D.
The kinetic energy of the particles is decreasing and the temperature is decreasing.

Answers

Answer:

A

Explanation:

i had answer it and it was A

please help me i will give brain list​

Answers

Answer:

a. pentane = C5H12

b. Heptane = C7H16

c. Hexyne = C6H10

d. Octene = C8H16

e. Nonane = C9H20

Hope it helps.

1-pentene

Molecular Formula C5H10

Condensed Structural FormulaCH2=CH(CH2)2CH3

Melting Point (°C)–138

Boiling Point (°C)30

2- heptane is the straight-chain alkane with the chemical formula H3C(CH2)5CH3 or C7H16, and is one of the main components of gasoline (petrol).

How many moles of Fe2+ are there in a 2.0g sample that is 80% by mass of FeCl2?

Answers

The number of moles of [tex]Fe^{2+}[/tex] in the [tex]2.0g[/tex] sample of [tex]FeCl_{2}[/tex] is [tex]0.0157[/tex] moles.

The following points should be noted about the number of moles:

The number of moles of any substance can be calculated using the mass and molar mass of the substance. [tex]n = \frac{mass}{molarmass}[/tex], where n is the number of moles.

Mass of the sample given as [tex]2.0g[/tex] and the molar mass of the sample as [tex]126.75g/mol[/tex].

Therefore, the number of moles of  [tex]Fe^{2+}[/tex]is obtained by dividing the mass by the molar mass.

Hence the number of moles is obtained as [tex]0.0175[/tex] moles.

Learn more about the number of moles here:

https://brainly.in/question/22534630

about how much of the visible side of the moon is lit up during a full moon?
A. Three fourths
B. One fourth
C. None of it
D. All of it

Answers

Answer:

D

Explanation:

i learned this in elementary

Based on the chemical equation, use the drop-down menu to choose the coefficients that will balance the chemical equation:

(
)BaO2 + (
)H2SO4 → (
)H2O2 + (
)BaSO4

Answers

Answer:

1

1

1

1

Explanation:

the equation is balancing

What is immigration and emigration

Answers

immigration is moving from current place to somewhere else whereaese emigration is reverse of it .

Answer:

well for me I think

Explanation:

immigration is the movement which involves an individual moving from a present place to another environment

That is going out

WHILE

Emigration is the process where a person comes into a particular environment

That means coming in

Help me if you know this pleaseeee

Answers

Answer:

help you with what?

Explanation:

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