Is freeze-drying a physical change or chemical change?

Answers

Answer 1

Answer:

Physical change because it can go back to its original form.

Explanation:


Related Questions

What is the momentum of a cat of mass 4 kg that is running south with a speed of 1.5 m/s?
A. 2.7 kg•m/s south
B. 6.0 kg•m/s south
C. 8.3 kg•m/s south
D. 7.1 kg•m/s south​

Answers

Answer:

option B is correct

Explanation:

momentum(p)=mv

mass= m=4 kg

velocity=v=1.5 m/s

P=4kg*1.5 m/s=6.0 kg.m/s

so option B is correct

the correct answer is b

What causes your skin to feel warm when it is in the sun on a summer day?
A Particles in the atmosphere reflect energy from the Sun downward.
B Hot particles from the Sun still carry some heat when they reach your skin.
C The solar wind carries heated air from the Sun's atmosphere to Earth's surface.
D The Sun radiates energy that passes through space and the atmosphere to your skin.

Answers

Answer:

idek akxkkwskkd nwkdkekekd

An overhead view of two people at the start of a maze. The person in a purple shirt has a line running forward, right, backward, right, forward, ending with an arrowhead pointing to a large gold star. The person in a green shirt has a line running forward, right, backward, right, forward, right, backward, right, forward, ending with an arrowhead pointing to a small gold star.
Zamir and Talia raced through a maze. Zamir walked 2 m north, 2 m east, 4 m south, 2 m east, 4 m north, 2 m east, 3 m south, 4 m east, and 4 m north. Talia walked 2 m north, 6 m east, 3 m south, 4 m east, and 4 m north.

Compare their distances:

Zamir walked
meters and Talia walked

Answers

Answer:

Zamir walked

27

meters and Talia walked

19

meters.

Explanation:

27 and 19

Answer:

zamir:27  Talia:19

Explanation:

i got it right on my test :)

10 POINTS PLS HELP
Combustion occurs when _____.

oxidation reactions are very slow
oxidation reactions are so fast the substance catches fire
oxygen is removed from another substance
machines use chemical energy to do work

Answers

Answer:  oxidation reactions are so fast the substance catches fire

Explanation:

Answer:

When oxidation reactions are so fast the substance catches fire

Explanation:

because i am big bwain

Choose all the answers that apply.

Which of the following energy forms are involved in a nuclear power plant?

heat
sound
mechanical
electrical
nuclear

Answers

Answer:

heat, electrical, mechanical, nuclear,sound

Explanation:

The power plant is mechanicalised so it produce heat which is in form of electrical and then we start hearing sound

Calculate the following quantity: molarity of a solution prepared by diluting 45.45 mL of 0.0404 M ammonium sulfate to 550.00 mL. M solution

Answers

Answer:

[tex]M_2=3.34x10^{-3}M[/tex]

Explanation:

Hello!

In this case, since a dilution process implies that the moles of the solute remain the same before and after the addition of diluting water, we can write:

[tex]M_1V_1=M_2V_2[/tex]

Thus, since we know the volume and concentration of the initial sample, we compute the resulting concentration as shown below:

[tex]M_2=\frac{M_2V_2}{V_1} =\frac{45.45mL*0.0404M}{550.00mL}\\\\M_2=3.34x10^{-3}M[/tex]

Best regards!

160 g or an element with a molar mass of 40 = __ moles?

Answers

Answer:

4 moles

Explanation:

The formula of finding moles is

moles = mass / molar mass, therefore

moles = 160 g / 40 g/mol = 4 moles

Regional Metamorphism occurs when great masses of rock are exposed to pressure. What does this typically form?

Answers

Answer:

Gneiss forms by regional metamorphism from both high temperature and pressure. Quartzite and marble are the most commonly used metamorphic rocks.

Help with 3.A and B image provided below​

Answers

a. P=0.971 atm=737.6 mmHg

b. n=2.88 x 10⁻³

Further explanation

Dalton's law of partial pressures states that the total pressure of a mixture of gases is equal to the sum of the partial pressures of the component gases

[tex]\tt P_T=P_1+P_2+..P_n[/tex]

A. vapor pressure of water at 22.5 = 20.4 mmHg

Pt=P H₂ + P H₂O

758 = P H₂ + 20.4

P H₂=737.6 mmHg=0.971 atm

B.Ideal gas Law = PV=nRT

P = 0.971 atm

V = 72 ml = 0.072 L

R = 0.082 L/atm mol

T = 22.5 + 273.15 =295.65

[tex]\tt n=\dfrac{0.971\times 0.072}{0.082\times 295.65}=2.88\times 10^{-3}[/tex]

22. In 4f12, the 12 stands for the

Answers

The 12 stands for the number of electrons that fill the f orbital

Further explanation  

In an atom there are levels of energy in the shell and sub shell  

This energy level is expressed in the form of electron configurations.  

Writing electron configurations starts from the lowest to the highest sub-shell energy level. There are 4 sub-shells in the shell of an atom, namely s, p, d and f. The maximum number of electrons for each sub shell is  

• s: 2 electrons  

• p: 6 electrons  

• d: 10 electrons and  

• f: 14 electrons  

4f¹² :

4 : number of shell

12 : the number of electrons that fill the f orbital

J.J. Thomson's plum pudding model of the atom followed the discovery of
A)
negatively charged particles with a very small mass.
B)
positively charged particles with a very large mass.
0)
negative electrons that revolved around a positive nucleus.
D)
positively charged protons that were contained in a concentrated area.

Answers

the answer is A i think from the options though the answers are worded a bit weird

J.J. Thomson's plum pudding model of the atom followed the discovery of negatively charged particles with a very small mass. Thus, the correct option for this question is A.

Who was J. J. Thomson?

J.J. Thomson was a British physicist who discovered sub-atomic particles known as electrons within an atom. He also announced that atoms are made up of smaller components.

The plum pudding model is defined by Thomson in order to demonstrate that negatively charged sub-atomic particles known as electrons are surrounded by a volume of positively charged particles known as protons. It is one of the historical scientific model of the atom that governs all sorts of properties of sub-atomic particles.

Therefore, "negatively charged particles with a very small mass" is the discovery that follows J.J. Thomson's plum pudding model of the atom. Thus, the correct option for this question is A.

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How many milliliters of alcohol are present in 720 mL of brandy?

Answers

Answer:

Answer : The volume of water and alcohol present in 675 mL of this solution is 405 mL and 270 mL respectively.

Explanation: As we are given that 40.0 % (v/v) alcohol solution. That means, 40.0 mL of alcohol present in 100 mL of solution.

Now we have to calculable the volume of alcohol in 675 mL solution.

As 100 mL of solution contains 40.0 mL of alcohol

So, 675 mL of solution contains alcohol

Thus, the volume of alcohol = 270 mL

Now we have to calculate the volume of water.

The volume of water = Volume of the solution - Volume of alcohol

Volume of water = 675 mL - 270 mL

The volume of water = 405 mL

Thus, the volume of water = 405 mL

Hence, the volume of water and alcohol present in 675 mL of this solution is 405 mL and 270 mL respectively.

The 720mL of an 80-proof brandy which is 40.0% (v/v) ethyl alcohol, contains 288 mL of ethyl alcohol.

What is volume/volume percentage?

The Percent solutions can be expressed in the form of volume/volume percentage, weight/volume percentage, or, weight/weight percentage. The concentration of the solution in percentage is calculated as the fraction of the weight or volume of the solute related to the total weight or volume of the solution.

The solution where concentration requires to be represented in volume percent (v/v%) when the solute is a liquid phase. It is also applicable to the numerator and the denominator in volume units and is called volume/volume percent.

Volume percentage = (Volume of solute/volume of solution) x 100

The given brandy has ethyl alcohol the v/v % is 40 %.

It means the 40 ml of ethyl alcohol is present in the 100ml of brandy

Given the volume of brandy = 720 ml

Volume of ethyl alcohol in 720 ml of brandy = (40/100)×720 = 288 ml

Therefore, 288 ml of ethyl alcohol is present in 720 ml of brandy which is 40.0% (v/v) ethyl alcohol.

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Your question is incomplete, but most probably complete question was,

An 80 proof brandy is 40.0% (v/v) ethyl alcohol. The "proof" is twice the percent concentration of alcohol in the beverage. How many milliliters of alcohol are present in 720 mL of brandy?

PLEASE HURRT I NEED HELP ASAP !!!!!!!!!!!!!!

Answers

Answer:

I think its b

Explanation:

well because thermal energy its connected to kidnetic energy

True or False: Scientists use what they know about the properties of different molecules to separate mixtures. *

Answers

Answer:

True

Explanation:

Mixtures are substances with indefinite composition. They consist of two or more elements  and or compounds in any proportion by mass.

Their constituents retain their identities i.e. physical properties are retained. Their constituents reacts differently to changed conditions. They can easily be separated into constituents by physical methods.

From these properties we can clearly identify that to separate mixtures, we use the differences in the chemical properties of the constituents of the mixtures.

Which is the Lewis structure for H3PO4? An upper P is single bonded above to an O, and to the left, right, and below to an O single bonded to an H. The O above the P has three pairs of dots to the left, above, and below; the O's to the sides have pairs of dots above and below, and the O below the P has pairs of dots right and left. A central upper P is single bonded left, right, above, and below to upper Os. The O above the P is single bonded to upper H on the left and the right, and has two electron dots above it. The O below the P is single bonded to an H below, and has pairs of electron dots to the left and right. A central upper P is double bonded to an O above, and single-bonded to an upper O single-bonded to an upper H to the left and the right. The O above the P has three pairs of electron dots, to the left, above, and to the right; the O's to the right and left have pairs of dots above and below. A central upper P is bonded to an upper H above, an upper O below, and upper O's bonded to upper H's to the left and the right. The O below the P has three pairs of electron dots, to the left, right, and below; the other two O's have pairs of dots above and below. A central upper P is double bonded to an O above, and single-bonded to an upper O single-bonded to an upper H to the left and the right. The O above the P has three pairs of electron dots, to the left, above, and to the right; the O's to the right and left have pairs of dots above and below.

Answers

Answer:

It is A.

Explanation:

I took the test.

The Lewis structure shows the arrangement of valence electrons in H3PO4.

The Lewis structure gives us a picture of the number of valence electrons in a molecule. This is because, in a Lewis structure, the electrons in the molecule are shown as dots. A single line may be used to show shared electrons in a covalent bond.

The correct Lewis structure of H3PO4 is an upper P is single bonded above to an O, and to the left, right, and below to an O single bonded to an H. The O above the P has three pairs of dots to the left, above, and below; the O's to the sides have pairs of dots above and below, and the O below the P has pairs of dots right and left.

Learn more: https://brainly.com/question/4144781

Boron has two isotopes. Boron-10 which has a mass of 10.0129 and Boran-11 with a mass of 11.0093 occurs 52.69% of the time and B - 11 47.31% of the time. What is the average atomic mass of boron?
Help me

Answers

Answer:

Copper, a metal known since ancient times, is used in electrical cables and pennies, among other things. ... Calculate the average atomic mass of copper. ... The atomic masses of the two stable isotopes of boron 10B (19.78%) and 11B (80.22%) are 10.0129 amu ... (.1978)(10.0129 amu) + (.8022)(11.0093 amu) =10.81 amu.

Explanation:

I hope I help :)

Which structure could a scientist look for in a plant that would identify it as a club moss rather than a liverwort?
O phloem
O spores
O rhizoids
O flowers

Answers

the answer is rhizoids

Answer:

what e said

Explanation:

What are the moles of silver metal produced from 0.0999 mol of copper?
_Cu(s)+_AgNO3(aq) -> _Cu(NO3)2(aq)+_Ag(s)

Answers

Answer:

1234567i9812345678912121212121

How many electrons are in the nucleus of an atom with an atomic number of
16?
O None. Electrons are not in the nucleus
08
O 16
O 32

Answers

Answer:

None. Electrons are not in the nucleus.

Explanation:

We know that an atom consist of electrons, protons and neutrons. Neutrons and protons are present inside the nucleus while electrons are present out side the nucleus. Electron has a negative charge and is written as e⁻. The mass of electron is 9.10938356×10⁻³¹ Kg . While mass of proton and neutron is 1.672623×10⁻²⁷Kg and 1.674929×10⁻²⁷ Kg respectively.

Symbol of proton= P⁺  

Symbol of neutron= n⁰  

The number of electron or number of protons are called atomic number while mass number of an atom is sum of protons and neutrons. The umber of protons and electrons are always equal to make the atom electrically neutral .

The atom having atomic number 16 have 16 electrons and these electrons are present out side the nucleus.

please help me out I need some ideas for cell city project or comic strip by tonight or if you did it already lemme copy it={​

Answers

Answer:

Can you give me your snap, so I can send you the foto

nitric acid, HNO3, and calcium hydroxide, Ca(OH)2


net ionic equation:

Answers

Answer:

2H⁺ (aq) + 2OH⁻ (aq) → 2H₂O (l)

General Formulas and Concepts:

Solubility RulesStrong Acids/Bases

Explanation:

Step 1: RxN

HNO₃ (aq) + Ca(OH)₂ (aq) → Ca(NO₃)₂ (aq) + H₂O (l)

Step 2: Balance RxN

2HNO₃ (aq) + Ca(OH)₂ (aq) → Ca(NO₃)₂ (aq) + 2H₂O (l)

Step 3: Ionic Equations

Total Ionic Equation:

2H⁺ (aq) + 2NO₃⁻ (aq) + Ca²⁺ (aq) + 2OH⁻ (aq) → Ca²⁺ (aq) + 2NO₃⁻ (aq) + 2H₂O (l)

Cancel out spectator ions.

Net Ionic Equation:

2H⁺ (aq) + 2OH⁻ (aq) → 2H₂O (l)

What is the formula for Copper i Monohydrogen Phosphate?​

Answers

Answer:

Na2HPO4

Explanation:

The chemical formula for Copper I Monohydrogen Phosphate is CuHPO₄.

Let's break down the formula to understand it better:

1. "Cu" represents copper, which is an element with the atomic symbol Cu. Copper is a transition metal that is commonly used in electrical wiring and plumbing.

2. "H" represents hydrogen, which is an element with the atomic symbol H. Hydrogen is the lightest and most abundant element in the universe.

3. "PO₄" represents the phosphate ion, which is composed of one phosphorus atom (P) and four oxygen atoms (O). The phosphate ion is commonly found in biological systems and is an essential component of DNA, RNA, and ATP.

So, when  combined one copper atom (Cu), one hydrogen atom (H), and one phosphate ion (PO₄),  get the formula CuHPO4, which represents Copper I Monohydrogen Phosphate.

It's important to note that the "I" in Copper I refers to the charge of the copper ion in this compound. Copper can form different ions with different charges, and the Roman numeral indicates the charge of the copper ion in this particular compound.

Thus,  chemical formula for Copper I Monohydrogen Phosphate is CuHPO₄.

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Please help!!!!!
Please help!!!!!

Answers

Answer:

1.B

2.A

3. B

Explanation:

1. A chemical bond is the physical phenomenon of chemical substances being held together by attraction of atoms to each other through sharing

2. so 2 is electrons of one atom are transferred permanently to another atom.meaning the answer is A

3. is When atoms combine by forming covalent bonds, the resulting collection of atoms is called a molecule. We can therefore say that a molecule is the simplest unit of a covalent compound.

A chemical bond is an attraction between two atoms.

A ionic bond is A bond formed when atoms transfer electrons.

Describe how this instrument works.

Operation:

Answers

Answer:

Microscope

Explanation:

Answer:

its a telescope you see stars or plants

Explanation:

Consider the two electron arrangements for neutral atoms A and B. What is the atomic number of A?
A - 1s?, 2s 2p6,35
B - 1s2, 2s 2p, 5s

Answers

Your answer is B: The outer electron of Adam B has moved to a higher energy state

Write the balanced net ionic equation for the reaction of aqueous sodium sulfate with aqueous lead(II) nitrate. Include phases.

net ionic equation:

Answers

Answer:

SO₄²⁻ (aq) + Pb²⁺ (aq) → PbSO₄ (s)

General Formulas and Concepts:

Solubility Rules

Explanation:

Step 1: RxN

Na₂SO₄ (aq) + Pb(NO₃)₂ (aq) → PbSO₄ (s) + NaNO₃ (aq)

Step 2: Balance RxN

Na₂SO₄ (aq) + Pb(NO₃)₂ (aq) → PbSO₄ (s) + 2NaNO₃ (aq)

Step 3: Ionic Equations

Total Ionic Equation:

2Na⁺ (aq) + SO₄²⁻ (aq) + Pb²⁺ (aq) + 2NO₃⁻ → PbSO₄ (s) + 2Na⁺ (aq) + 2NO₃⁻ (aq)

Cancel out spectator ions.

Net Ionic Equation:

SO₄²⁻ (aq) + Pb²⁺ (aq) → PbSO₄ (s)

Naming inconic compounds and lots of iconic naming

Answers

if you just look up the answer it comes up btw!!

have a great day

When comparing plant and animal cells which statement is least accurate?
Plant cells have a cell wall and animal cells do not.
Plant cells have chloroplasts and animal cells do not.
Plant cells have a large central vacuole and animal cells do not.
Plant cells have cell membranes and animal cells do not.

Answers

Here is a diagram comparing both plant and animal cells.
Hope it helps:)

Just wanted to know what the response time is :)

Answers

Bshsibeidbeifhdbeuu hi chh in Chen but by uh hi in vcucbxbxbxbxbcbcbcbcbcbdjcjfjc
Too fast
I get my answers in just 2-3mins or atleat 30sec

The correct chemical formula for aluminum (Al+3) plus chlorine (Cl-1) is what.

Answers

Answer:

AlCl₃

General Formulas and Concepts:

Elemental ChargesReading a Periodic Table

Explanation:

Step 1: Define

Al³⁺ and Cl¹⁻

Step 2: RxN

Al³⁺ (s) + Cl¹⁻ (g) → AlCl₃

Need to have the same amount of charge (should add to 0)We need 3 Cl's to balance the positive 3+ charge3(-1) for Cl + 1(3+) for Al = 0

Answer:

The answer is: AlCl₃

Hope this helped :)))

Explanation:

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