What do we mean when we say a substance is "pure"?

Answers

Answer 1

Answer:

A pure substance is a substance that is only made up of atoms of one element and so it has fixed melting and boiling points.


Related Questions

Which list of elements from Period 2 is arranged in decreasing
ionization potential?

Answers

Answer:

It’s ionisation

Explanation:

Please help if you can !

Answers

Answer:

7630

Explanation:

eAnswer:

Explanation:

Math

what are the coefficients for the reaction _Cl2O5+_H2O>_HCIO3 once it is balanced

Answers

Answer:

1.9472857e+56

Explanation: Ask Google

how can i separate water salt starch​

Answers

Decantation
Centrifugation
Filtration
Evaporation

Answer:

By Boiling Them soo water can evaporate and separates from salt.

(PLEASE HURRY) Which of the following statements is an example of quantitative data? A. There are ten butterflies. B. The butterflies are red with yellow spots. C. The butterflies are eating nectar from the flower. D. The butterflies are flying.

Answers

answer: a
explaination: it said it needs to be 20 characters but the answer is a

A chemist carefully measures the amount of heat needed to raise the temperature of a 341.0 mg
sample of a pure substance from 8.4 ℃
to 21.5 ℃. The experiment shows that 4.03 J of heat are needed.

- What can the chemist report for the specific heat capacity of the substance?

Answers

Answer:

The specific heat of substance is 0.90 j/g.°C.

Explanation:

Given data:

Mass of sample = 341.0 mg (341.0/1000 = 0.341 g)

Initial temperature = 8.4 °C

Final temperature = 21.5 °C

Heat needed = 4.03 J

Specific heat capacity of substance = ?

Solution:

Specific heat capacity:

It is the amount of heat required to raise the temperature of one gram of substance by one degree.

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

ΔT = T2 - T1

ΔT = 21.5 °C - 8.4 °C

ΔT = 13.1 °C

4.03 J = 0.341 g × c ×13.1 °C

4.03 J = 4.4671 g.°C  × c

c = 4.03 J  /4.4671 g.°C

c= 0.90 j/g.°C

The specific heat of substance is 0.90 j/g.°C.

In the reaction Zn H 2SO 4→ ZNSO4 + H2, which, if any element is oxidized

Answers

Answer:

I hope this answer is correct

Explanation:

This is an oxidation-reduction (redox) reaction:

Zn0 - 2 e- → ZnII (oxidation)

2 HI + 2 e- → 2 H0 (reduction)

Zn is a reducing agent, H2SO4 is an oxidizing agent.

Reactants:

Zn

Names: Zinc source: wikidata, accessed: 2019-09-07, Zinc powder (pyrophoric) source: ICSC, accessed: 2019-09-04, Zn source: wikidata, accessed: 2019-09-07

Appearance: Grey-to-blue powder source: ICSC, accessed: 2019-09-04

H2SO4 – Sulfuric acid source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-07source: NIOSH NPG, accessed: 2019-09-02

Other names: Oil of vitriol source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-07source: ICSC, accessed: 2019-09-04source: NIOSH NPG, accessed: 2019-09-02, Sulfuric acid, concentrated (> 51% and < 100%) source: ICSC, accessed: 2019-09-04, H2SO4 source: wikidata, accessed: 2019-09-07

Appearance: Clear, colorless liquid source: wikipedia, accessed: 2019-09-27; Odourless colourless oily hygroscopic liquid source: ICSC, accessed: 2019-09-04; Colorless to dark-brown, oily, odorless liquid. [Note: Pure compound is a solid below 51°F. Often used in an aqueous solution.] source: NIOSH NPG, accessed: 2019-09-02

Products:

ZnSO4 – Zinc sulfate source: wikipedia, accessed: 2019-09-27source: wikidata, accessed: 2019-09-02source: ICSC, accessed: 2019-09-04

Other names: White vitriol source: wikipedia, accessed: 2019-09-27, Goslarite source: wikipedia, accessed: 2019-09-27, Zinc sulfate (1:1) source: wikidata, accessed: 2019-09-02

Appearance: White powder source: wikipedia, accessed: 2019-09-27; Colourless hygroscopic crystals source: ICSC, accessed: 2019-09-04

H2

Names: Dihydrogen source: wikidata, accessed: 2019-09-07, Hydrogen source: ICSC, accessed: 2019-09-04source: wikidata, accessed: 2019-09-07, H2 source: wikidata, accessed: 2019-09-07

Which one of the following statements about the β-sheet is FALSE? The β-sheet is a type of regular secondary structure. β-sheets can be parallel or antiparallel. The β-sheet contains hydrogen bonds between the carbonyl oxygen of one residue and an amide hydrogen of a residue on an adjacent strand. The side chains in a β-sheet alternate between the two sides of the sheet. The β-sheet is a type of secondary structure that fulfills the hydrogen bonding requirements of amino acid side chains. g

Answers

Answer:

The correct answer is "The β-sheet is a type of secondary structure that fulfills the hydrogen bonding requirements of amino acid side chains".

Explanation:

Hydrogen bonding are among the most common chemical bonds that occur between amino acids, where one atom of an amino acid acts as an hydrogen donor and the other acts as hydrogen acceptor. It is not true that β-sheet fulfills the hydrogen bonding requirements of amino acid side chains. β-strands are directional and form hydrogen bonds in antiparallel, parallel, or mixed arrangements. In the parallel form adjacent amino acids do not form hydrogen bonds, but they bond with the residues that flank the other.

The statement related to β-sheet that is considered to be false is that it should be the type of the secondary structure.

What is Hydrogen bonding?

It is the bonding that should be arise mainly with the chemical bonds that lies between the amino acids where one atom should be acted as the donor of hydrogen and the other should be like an acceptor of hydrogen. Also, β-strands should be considered as directional and create the hydrogen bonds in the anti-parallel or mixed arrangements.

Learn more about bonds here: https://brainly.com/question/17957192

HELP!!!!
An unknown gas effuses at a rate of 2.0 times the rate of CL2. What is the molar mass of the unknown gas?

Answers

The molar mass of the unknown gas is 17.75 g/mol  

From Graham's law of diffusion, we understood that the rate of diffusion of a gas is inversely proportional to the square root of the molar mass of the gas as shown below:

R ∝ [tex]\frac{1}{\sqrt{M}}[/tex]

Expanding further, we have

[tex]\frac{R_{1} }{R_{2} } = \sqrt{\frac{M_{2}}{M_{1}} }[/tex]

Where

R₁ and R₂ are the rate of diffusion of the individual gas

M₁ and M₂ are the molar masses of the individual gas.

With the above information in mind, we can obtain the molar mass of the unknown gas as follow:

Let R₁ be the rate of the unknown gas

Let R₂ be rate of Cl₂ gas

Let M₁ be the molar mass of the unknown gas

Let M₂ be the molar mass of the Cl₂ gas

From the question given above, we were obtained the following:

Rate of the unknown gas = 2 times the rate of Cl₂ i.e

R₁ = 2R₂

Molar mass of Cl₂ (M₂) = 2 × 35.5 = 71 g/mol

Molar mass of the unknown gas (M₁) =?

[tex]\frac{R_{1} }{R_{2} } = \sqrt{\frac{M_{2}}{M_{1}} }\\\\\\\frac{2R_{2}}{R_{2} } = \sqrt{\frac{7 1}{M_{1}} }\\\\2 = \sqrt{\frac{7 1}{M_{1}} }[/tex]

Square both sides

[tex]2^{2} = \frac{71}{M_{1}} \\\\4 = \frac{71}{M_{1}}[/tex]

Cross multiply

4 × M₁ = 71

Divide both side by 4

[tex]M_{1} = \frac{71}{4}[/tex]

M₁ = 17.75 g/mol

Therefore, the molar mass of the unknown gas is 17.75 g/mol

Learn more: https://brainly.com/question/10408961

if i change it by looking at it what type of change is it ?
non impact
kinetic
physical
chemical

Answers

Answer:

the answer to this is non impact

what are they waiting? or what are their waiting?

please correct me if I'm wrong​

Answers

Hm I’m confused, if you mean what are they weighting, it’s they :)

what is it called when an object is being partially or tottally blocked by another object in space​

Answers

An eclipse is when two celestial bodies lines up in space and one of the objects gets partially or totally blocked. This could happen when the sun blocks the moon, or when the moon blocks the sun. These are just some of the examples there are many others out there, so the answer would be Eclipse!


Hope this helps and stay safe!

Enter the cycle number, n, in the x column and the number of radioactive atoms in the y column. When you finish, resize the window.

Answers

Answer:

at first click done,

A: exponential

then, i just put 0.5, and somewhat close.

Explanation:

edge 2021!!!

Which of the following planets has ammonia clouds in its atmosphere?

Jupiter
Mars
Mercury
Venus

Answers

Answer:

Jupiter and Saturn has ammonia clouds in its atmosphere since the molecules of ammonia gas that are present in their atmospheres condense to form clouds. However, these ammonia clouds are more visible in Jupiter than in Saturn because of their lower altitude in Saturn.

Answer:

A

Explanation:

i took the exam

40. Which of these is an example of an
anhydrous compound?
A) H2O
C) CuSO4.5H2O
B) CaSO4
D) CaSO4 · 2H2O

Answers

Explanation:

CuSO4.5H2O and CaSO4.2H2O

Answer:

CaSO4 is an example of anhydrous compound

Reason:

Calcium Sulphate (CaSO4) does not contain water in its crystal structure, unlike other minerals.

The two alternative chair conformations of cis-1-bromo-2-methylcyclohexane differ in their Gibbs free energy. Using the data for ΔG (Axial-Equatorial) for monosubstituted cyclohexanes at room temperature (25ºC): Axial → Equatorial Group ΔG° (kJ/mol) Group ΔG° (kJ/mol) -0.8 -5.9 -2.4 -7.3 -3.9 1,2-gauche 3.8 Calculate the absolute value of the difference in the Gibbs free energy between the alternative chair conformations. kJ/mol Which group in this compound is in axial position in the energetically preferred chair conformation? _______

Answers

Answer:

a.) 4.9kj/mol

b.) -Br group

Explanation:

first all of your question did not make mention of the groups in the table.

here it is:-

axial group     ΔG°(kj/mol)    group     ΔG°kj/mol

CN                   -O.8                NH₂          -5.9

Br                     -2.4                 CH₃           -7.3

OH                    -3.9            1,2-gauche      3.8

The 6 axial groups are bonded one on each carbon and also they are parallel and also alternate from up to bottom.

a.)

to get the absolute ΔG;

ΔG = -2.4-(-7.3)

= -2.4+7.3

= 4.9KJ/MOL

b.)

the axial group in this compound which is in the axial position in the energetically preferred chain conformation is the -Br group

Please check attachment for diagram

Chocolate drink can easily be dissolved in

Answers

Answer:

Chocolate drink can easily be dissolved in Hot water than cold water.

Explanation:

Chocolate drink can easily be dissolved in Hot water than cold water because hot water has more heat or thermal energy than cold water. When water is heated and becomes hot, the molecule of water gain alot of energy and this make it to move very fast and as these molecules move faster, they begin to come in contact with the molecules of chocolate drink, thereby making it to dissolve faster than that of cold water.

What is one way the lack of gravity in space affects the human body?
Please help ASAP

Answers

Answer:

Loss of muscle mass because there is no weight on the back and legs.

Explanation:

How many electrons are in the 4p orbital does Br possesses?

Answers

Answer:

5 electron

It contains 6 electrons in 2p orbital, 6 electrons in 3p orbital and 5 electron in 4p orbital.

Which substance cannot be broken down by chemical changes? Magnesium Hydroxide Carbon Dioxide b O Ammonia Iron​

Answers

Answer:

Iron

Explanation:

The only substance that cannot be broken down by a chemical change is Iron.

Iron is an element and elements are made up of atoms. Atoms are the smallest indivisible particles that takes part in chemical reactions.

Other choices are compounds. Compounds are made by combining atoms together through the loss, gain or sharing of electrons. This interaction creates bonds between two or more species. But for substances made up of atoms alone, no bonds are formed and hence, they cannot be further broken down.

Which of the following is an example of a chemical name using prefixes?
O A. Carbon dioxide
O B. Magnesium sulfate
O C. Iron(ll) carbonate
O D. Potassium chloride

Answers

A.Carbon dioxide because I had the question on my test and I got it right

Answer:

A

Explanation:

how many atoms are in 20 grams of aluminum ​

Answers

Answer:

4.5 × 10²³ number of atoms Al

Explanation:

Given data:

Mass of Al = 20 g

Number of atoms of Al = ?

Solution:

The given problem will solve by using Avogadro number.

'It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance" .The number 6.022 × 10²³ is called Avogadro number.

We will calculate  the number of moles of Al first:

Number of moles = mass/molar mass

Number of moles = 20 g/ 27 g/mol

Number of moles = 0.74 mol

1 mole = 6.022 × 10²³ number of atoms

0.74 mol ×  6.022 × 10²³ number of atoms / 1 mol

4.5 × 10²³ number of atoms Al

The required number of atoms is [tex]4.46\times 10^{23}[/tex]

Atomic Weight:

Atomic weight, also called relative atomic mass, ratio of the average mass of a chemical element’s atoms to some standard.

Given that,

Mass=[tex]20[/tex] grams

1 mole of aluminum [tex]= 27g = 6.023\times10^{23}[/tex] number of atoms 27g of aluminum contains [tex]6.023\times10^{23}[/tex] a number of atoms.

Therefore,20 grams the number of atoms is,

[tex]6.023\times10^{23}\times\frac{20}{27} =4.46\times10^{23}[/tex]

Learn more about the topic of atomic weight:

https://brainly.com/question/13399225

2 What do you notice about the location of the elements in each family?​

Answers

Explanation:

They are indeed placed from the far left hand side of the periodic table in almost the same column. If you step around the table between left to right, the movement of electrons rises by one. When you progress down the line, the number of power increases by the one.

The diagram shows structures that represent different levels of organization in a human. Which is the simplest level of organization?
W
X
Y
Z

Answers

Answer: the answer is Z

Explanation:

Becuase the order from smallest to largest would be:

Y: Cell

Z: Tissue

W: Organ

X: Organ system

What are the steps to
separate iron fillings, water,
leaves?

Answers

Answer:

Wrap a magnet in plastic lunch wrap and move it through the mixture of the three solids. The iron filings will stick to the magnet. The filings can be removed by unwrapping the plastic from the magnet carefully! Mix the remaining salt and sand in water and stir.

Explanation:

Aspirin synthesis involves the addition of an acetyl group to salicylic acid in a condensation reaction with an alcohol. The acetyl group could be added with a carboxylic acid but the preferred procedure is to use the acid anhydride. Why is preferable to use an acid anhydride for ester formation with an alcohol rather than a carboxylic acid? Select one: Carboxylic acids react with water in an undesired side reaction. Acid anhydrides are generally easier and safer to handle than carboxylic acids. Carboxylic acids change the pH of the solution too much for the reaction to proceed. Acid anhydrides are less stable than esters so the equilibrium favors the ester product.

Answers

Answer:

The correct appropriate will be Option 1 (Acid anhydrides are less stable than esters so the equilibrium favors the ester product.)

Explanation:

Acid anhydride, instead of just a carboxyl group, is typically favored for esterification. The predominant theory would be that Anhydride acid is somewhat more volatile than acid. This is favored equilibrium changes more toward the right of the whole ester structure. Extremely responsive than carboxylic acid become acid anhydride as well as acyl chloride. Thus, for esterification, individuals were most favored.

The other options offered are not relevant to something like the scenario presented. So, the solution here is just the right one.

help me please i don’t understand the problem

Answers

Answer:

Atoms are neither created or destroyed.

Explanation:

The end result of a chemical change does not create or destroy any atoms. Matter cannot be created or destroyed, meaning the same amount of atoms exist before and after the change.

A. Atoms are neither created nor destroyed

Which type of atom will attract electrons

Answers

Answer:

nuetrons and protons

Explanation:

Explanation:

the electron pair will be attracted more strongly to the atom that has the higher electronegativity

hope it help

Is a nickel coin magnetic

Answers

Answer:

Yes

Explanation:

Because it was false because it has been the substance abuse permalink

yes they are magnetic

Help me please I need help

Answers

Answer:

uijj uhh the yuk high uijj john

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