A student mixes 20.0gof white KCl crystals with distilled water in a beaker. After the mixture was stirred, no crystals are visible and the solution is clear. After several days, all of the water evaporates and white crystals are found in the beaker. Which of following pieces of experimental evidence would best help the student to confirm that a new compound had not been made and that only a physical change occurred?
a- The solution does not change color after stirring.
b- The KCl crystals are no longer visible after mixing with water.
c- There is a temperature change in the solution during the dissolving process.
d- After the water has evaporated, the white crystals in the beaker have a mass of 20.0g

Answers

Answer 1

Answer:d

Explanation: over time water evaporates which leaves you with the white crystals mass

Answer 2

A student in a beaker mixes 20.0 g of white KCl crystals with distilled water; no crystals are visible, and the solution is clear, indicating that the physical change has occurred, which is that after the water has evaporated, the white crystals in the beaker have a mass of 20.0 g; that is option d.

What is the significance of the physical change?

The physical change includes the change in the shape and size of the substances but not the chemical change, as in the case of here the crystal, which is left behind after the evaporation of the solution without any change in the chemical composition.

Hence, a student in a beaker mixes 20.0 g of white KCl crystals with distilled water; no crystals are visible, and the solution is clear, indicating that the physical change has occurred, which is that after the water has evaporated, the white crystals in the beaker have a mass of 20.0 g; that is option d.

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Related Questions

which aqueous solution has the lowest vapor pressure?

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Answer:

Since all of them are aqueous solutions, the solvent in each solution is H2O. Based on the Raoult's Law, we only have to determine which solution contains the highest mole fraction of the solvent, H2O. The solution that will have the lowest vapor pressure is a. 0.20 m Na2SO4.

Explanation:

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[EARTH SCIENCE]

Hi, can anyone help please? Thank uuuu!!! :D

The relationship between the average distance of a planet from the sun and the planet’s orbital period is described by the....

A. Law of ellipses.
B. Law of equal areas.
C. Law of motion.
D. Law of periods.

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Answer:

c. law of motion

Explanation:

I think I hope it helps

The material used as a biological sensor is one dimension of 20 mm, the other Are in nanometers ​

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Answer: 20 , 40

I want know the answer now !

When drawing an atom, we draw the same number of electrons as
protons


Select one:

True

False


Answers

Answer:

true

I hope it helps.

The diagram shows Earth's position in its orbit around the Sun at the beginning of each season

Which position of Earth shows the Moon located where its shadow may sometimes reach Earth?

Answers

The position where the moon is located where its shadow may sometimes reach Earth is position A .

What is an eclipse?

We know that in the outer space there are a lot of celestial bodies that can be found. Now we know that a celestial body is one that can be found in the outer space and the moon and the sun are all parts of the celestial bodies that we can find in the solar system.

In this case we  are being asked for the position of the moon that could lead to an eclipse where the moon would come between the earth and the sun and that is the position A.

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Who ever gets it right I will give brainly and 20 points

Answers

Answer:

LETTER C it can apply a greater output force over a greater distance compared to the input force and distance

Explanation:

i just know cause im smart like that

The density of iron is 7.0 g/cm'. What volume of iron would have a mass of 14.0 g?

Answers

Answer:0.284ib/in 3

Explanation:

[tex]\text{Given that,}\\\\\text{Density of iron, }~ \rho = 7 ~\text{g cm}^{-3} = 7 \times 10^{3}~ \text{kg m}^{-3}\\\\\\\text{Mass, m =14 g =} ~ 14 \times 10^{-3} ~\text{kg}\\\\\\\text{Volume of iron,}~ V = \dfrac{m}{\rho} = \dfrac{14 \times 10^{-3}}{7\times 10^{3}} = 2 \times 10^{-6} ~~ m^3[/tex]

The molecular formula for a compound with a molar mass of 180.18g that contains 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass is

Answers

Answer:

C6H12O6

Explanation:

First you need to find the empirical formula by the percents that they're giving you. You assume that is 100 grams and if for example you have 40% of carbon you will have 40 grams of carbon.

1.Find the number of moles of each atom

C: 40g÷12g/mol= 3.33 mol

H: 6.7g÷1g/mol= 6.7 mol

O: 53.3g÷16g/mol= 3.33 mol

You divide all ratios by the minimum ratio and you obtain the empirical formula

CH2O

Since you're given the molar mass, you now have to find the molar mass of CH2O by adding the molar mass of each element present and repeated in the compound.

CH2O= 30g/mol

Now you know that the molar mass of the molecular formula we are looking for is 180.18 g/mol, and since the empirical formula is the molecular formula in its smaller ratio, by logic you can say that:

180.18g/mol ÷ 30g/mol= 6

So, you now know that the empirical formula is being multiplied by a factor of 6 to reach a compound with a molar mass of 180.18g/mol, so you multiply each subscript of the empirical formula by 6 obtaining:

C6H12O6

what is meant by the term symbol of an element?​

Answers

An element symbol is a one- or two-letter abbreviation for a chemical element name. When a symbol consists of two letters, the first letter is always capitalized, while the second letter is lowercase. Element symbols also can refer to alchemy symbols for the elements or to the symbols used to describe isotopes.

Study hard!

Sodium has a density of 1.95 g/mL If the volume of some sodium is 9.0 L what is the mass

Answers

Answer:

17550g

Explanation:

You want to use the equation D=M/V. You are given density in g/mL, so you just need to multiply that by 9L, but first you want the mL and L to match, so you change the 9L to 9000mL (knowing there is 1000mL in 1L). Then solve algebraically by multiplying the 9000mL and the 1.95g/ml, making the mL cancel, leaving you with your answer in grams.

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what is the oxidation number of sulfur in the sulfate ion?

Answers

Answer:

+6

Explanation:

Which description of salt is a physical property?

Answers

Answer:

White being the color and coming in small grains.

Explanation:

Physical properties are something you can clearly see about the object.

Answer:

Hey mate......

Explanation:

This is ur answer....

It was in the lesson, the answer is it is solid and does not conduct electricity.

 

Physical Properties                                 Chemical Properties

White cubic crystals                                 Do not undergo combustion

Odorless, salty taste                                 Make ionic bonds easily

As solids, they do not conduct electricity  The product of mixing acids and bases.

Hope it helps!

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Two goldfish different parents.One fish has a split tail and the other does not.Why do the goldfish have tails with different shapes?

a.Each goldfish has a different tail shape because offspring from different parents will have different tail shapes.

b.Each goldfish has a different tail shape because they have different versions of the gene for tail shape that connect together to make different tail shapes.

c.The goldfish have different versions of the gene for tail shape.The genes are split inside one goldfish's tail but not inside the other's

The goldfish have different versions of the gene for tail shape,which instuct for different proteins that connect in different ways to make different tail shapes.

Answers

Answer:

A I believe is your best choice.

Explanation:

Name one nutrient indicator and explain how it works.

Answers

Answer:

Hi this is Adhira please make me as brainlist

Explanation:

The nutritional status indicators for the CDC Growth Charts include obesity, overweight, underweight, and short stature. Percentiles are used to rank an individual or a group on a growth chart and indicate where either fits in the context of the reference population

A student pours ammonium nitrate into a container of room temperature water. The student stirs the mixture with a stirring rod and then feels the outside of the container, which is cold to the touch. Which material is part of the system that absorbed heat?

the water

the air

the stirring rod

the container

Answers

The material that absorbs the heat of the system is water owing to its high specific heat capacity.

The specific heat capacity of a substance refers to the amount of heat that is capable of increasing the temperature of 1 Kg of a body by 1 K. The higher the specific heat capacity, the more the amount of heat that the body can absorb without temperature change.

The material that absorbs the heat of the system is water because water has a higher specific heat capacity than all the other materials present.

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The material which is part of the system that absorbed heat is; The water.

Discussion:

According to the question;

Water was initially at room temperature.We know by convention, ammonium nitrate is a cold substance.

In essence, the heat liberated from the system must have been absorbed by the water so that the outside of the container after mixing becomes cold.

This is so because water has a high specific heat capacity.

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one liter of gas has a pressure of 150.00kPa at 25 degrees celcius. if the pressure increases to 600.kPa and the temperature to 100.0 degrees celcius, what would be the new volume of the gas

Answers

Answer:

0.313 liters

Explanation:

You want to use the Combined Gas Law Equation: (P1*V1)/(n1*T1)=(P2*V2)/(n2*T2). You then want to cross off things that don't change, so moles(n) in this example. Then convert the temperature to Kelvin (always), and solve algebraically.

Please read question

Answers

Answer:

cant see it

Explanation:

Calculate the molar mass of NH4NO3. Molar mass of NH4NO3 = g/mol.

Answers

The molar mass of NH4NO3 in g/mol is 80g/mol.

HOW TO CALCULATE MOLAR MASS:

The molar mass of a compound can be calculated by summing the atomic masses of its constituent elements.

In ammonium nitrate (NH4NO3), there are nitrogen, hydrogen, and oxygen elements.

Atomic mass of nitrogen = 14Atomic mass of oxygen = 16Atomic mass of hydrogen = 1

Molar mass of NH4NO3 = 14 + 1(4) + 14 + 16(3)

Molar mass of NH4NO3 = 80g/mol

Therefore, the molar mass of NH4NO3 in g/mol is 80g/mol.

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Answer:

80g/mol

Explanation:

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explain the concept of kenetic molecular theory

Answers

Not sure if you meant kinetic.. The theory states that gas particles are in constant motion and exhibit perfectly elastic collisions. The theory is based on the idea that matter is composed of tiny particles that are always in motion.

Round off your answer to one decimal place.

Answers

Answer: 10.4

Explanation:

ph is just as follows:

[tex]pH = -log[H_{3}O^{+}][/tex]

So plugging in our concentration we get:

[tex]-log(4.45*10^{-11})=10.35163999...[/tex]

Then rounding to one decimal place takes us to pH = 10.4

Deval drew the models of particles in a substance shown below. Which model best represents the particles in solid

Answers

Answer:

it would be the second one thank me later

Explanation:

Question 12 of 35
Which two specialized structures allow amphibians to live on land?
O A. Gills
B. Lungs
C. Legs
D. Tail
SUBMIETI

Answers

Answer:

B and C

Explanation:

Most animals that live underwater have have gills and tails and vise versa hope this helps!

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If a 425 gram sample of Uranium-235 had a half-life of 8 days, how much of the sample would remain after 16 days?
type your answer
grams

Answers

What is half of 425 grams? Ok. 212.5 alright. Now half that - 106.25 grams I think.

what describes the pool of electrons in metallic bonding?

Answers

In metallic bonding, the electrons are “surrendered” to a common pool and become shared by all the atoms in the solid metal. Metallic bonding is found in metals and their alloys. When the atoms give up their valence electrons, they form ions. These ions are held together by the electron cloud surrounding them.

Consider the substances quartz (SiOs), gold (Au), and nitrogen gas (N2). If possible, use the terms
molecule and compound to describe each substance. If one or more of the substances cannot be
described by the terms molecule and compound, explain why not.

Answers

Answer:

Silicon Dioxide is a compound usually referred to as Quartz, it's a crystalline sort of material that is commonly found and used for equipment and furniture (like tables for example). Their molecular geometry is of tetrahedral shape (how their bonds look like and such)

Gold is an element that is a transitional metal that is quite malleable (able to hammer it to sheets) and is ductile (can be made into wires). As you probably have guessed, gold is used a lot for jewelry due to its lustrous appearance, and the fact that it can't corrode as well as its rarity. Due to it not being able to corrode, it's pretty useful in circuitry as it requires less management unlike elements with higher electrical conductivity like copper or silver. However gold is pretty costly so it's not often relied on for technology and mostly just used for show instead.

N2 or nitrogen gas, may seem like a compound for people new to chemistry but is actually just a diatomic molecule, meaning they are composed of only 2 atoms. So elements that are diatomic are commonly found with only 2 atoms (Oxygen gas for example, or Hydrogen gas) Nitrogen is part of the "magnificent seven" (the elements which are diatomic".  Nitrogen is essential for a lot of living things (aside from us), and since they are the most abundant material in our air (78% of air is Nitrogen), there's plenty of life growing.

Compound and elements are differ from each other. Silicon dioxide ( SiO₂ ) is compound , gold ( Au ) is  element and nitrogen gas ( N₂ ) is compound.

What is difference between molecule and elements ?

Elements are always made-up of only one type of atom. Molecule is made up of more than one type of atom. Silicon dioxide is a compound, which is crystalline in nature. Their molecular geometry is of tetrahedral shape.

Gold is an element that is a transitional metal that is quite malleable and is ductile.  Gold ( Au ) is used a lot for jewelry. Nitrogen gas is  compound . It is diatomic in nature, So elements that are diatomic are commonly found with only 2 atoms.

Hence, silicon dioxide is compound, gold is element, and nitrogen gas is also compound.

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discuss why people use the scientific method

Answers

Answer:

They use the scientific method to study different aspects of how people think and behave. They also use the scientific method because it is evidence-based, standardized and objective in conducting experiments.

Calculate the mass of nitric acid required to make a 250mL solution with 2.40 ph

Please show steps, I am trying to learn!

Answers

The mass of nitric acid required to make the given solution is 0.0627 g.

The given parameters:

Volume of the acid, V = 250 mLpH of the acid, = 2.4

The hydrogen ion (H⁺) concentration of the nitric acid is calculated as follows;

[tex]H^+ = 10^{-pH}\\\\H^+ = 10^{-2.4}\\\\H^+ = 0.00398[/tex]

The molarity of the nitric acid is calculated as follows;

[tex]= 0.00398 \ H^+ \times \frac{1 \ M \ HNO_3}{1 \ H^+} \\\\= 0.00398 \ M[/tex]

The number of moles of the nitric acid is calculated as follows;

[tex]moles = M\times L\\\\moles = 0.00398\ M \ \times \ \frac{250 \ mL}{1000} \\\\moles = 9.95 \times 10^{-4} \ mol.[/tex]

The molar mass of nitric acid is calculated as;

[tex]HNO_3 = (1) \ + (14) \ + (16 \times 3) = 63 \ g/mol[/tex]

The mass of the nitric acid contained in the calculated number of moles is calculated as;

[tex]mass = moles\ \times \ molar \ mass\\\\mass = 9.95\times 10^{-4} \ mol. \ \times \ 63 \ g/mol\\\\mass = 0.0627 \ g[/tex]

Thus, the mass of nitric acid required to make the given solution is 0.0627 g.

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Choose all the answers that apply.

What’s is the freezing point of water?

1. 0’c

2.32’c

3.32’F

4.0’F

Answers

Answer: The answers are the first and third options.

Answer:

1.0'c

3.32'f

Explanation:

What is the amplitude of the above wave?

Answers

Answer:Amplitude in a longitudinal wave

Explanation:Wave amplitude of a longitudinal wave is the distance between particles of the medium where it is compressed by the wave. Wave amplitude is determined by the energy of the disturbance that causes the wave. A wave caused by a disturbance with more energy has greater amplitude.

which colour would you expect ekasilicon to be

Answers

Answer:

it would ether be gray to black or silver to gray and black

Explanation:

because of my calculation ekasillicon would be that color because of the eyes and because of your color seeing .

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