Why is it important to use chemicals of high quality (purity) and exact(correct) concentrations in experiments?​

Answer:

please I don't understand the question, rewrite it

Explanation:

1 sugar solution =Distillation

2 Iron powder and sand=magnetic separation

3 petrol and diesel= Fractional distillation

4 Camphor and glass powder = Sublimation

coal

Which of these can be mined from earth and used as an energy source?

A.Get rid of the waste and extra fluid

B.Ureters

C.Coal

D.Bladder

ans is coal

Answer:

H = 6

O = 6

Fe = 3

Total atoms = 15

Explanation:

3Fe (OH)2

Fe = 1×3

O= 2× 3 = 6

H= 2× 3 = 6

Total atoms = 6+6+3=15

I hope I helped you^_^

Taking into account the definition of density and change of units, if a container is strong enough to hold 62.0 pounds (lb) of gasoline, you can put 10.3184 gallons in there.  

First you must know that density is defined as the property that matter, whether solid, liquid or gas, has to compress into a given space.

In other words, density is the relationship between the weight (mass) of a substance and the volume it occupies (that same substance). Then, the expression for the calculation of density is the quotient between the mass of a body and the volume it occupies:

[tex]density=\frac{mass}{volume}[/tex]

On the other side, the rule of three is a way of solving problems of proportionality between three known values and an unknown value, establishing a relationship of proportionality between all of them.

That is, what is intended with it is to find the fourth term of a proportion knowing the other three.  

If the relationship between the magnitudes is direct, that is, when one magnitude increases, so does the other (or when one magnitude decreases, so does the other) , the direct rule of three must be applied.

To solve a direct rule of three, the following formula must be followed, where a, b and c are known values ​​and x is the value to be calculated:

a ⇒ b

c ⇒ x

So, [tex]x=\frac{cxb}{a}[/tex]

The direct rule of three is the rule applied in this case where there is a change of units. To perform conversion of units from pounds to grams, you must first know that 1 lb = 453.59 g. So, if 453.59 g is 1 lb, how many grams equals 62 lb?

[tex]mass= \frac{62 lbx453.59 g}{1 lb}[/tex]

Solving:

mass= 28122.58 grams

Then, you know:

Replacing in the definition of density:

[tex]0.720\frac{g}{cm^{3} }=\frac{28122.58 g}{volume}[/tex]

Solving:

volume×0.720 [tex]\frac{g}{cm^{3} }[/tex]= 28122.58 g

[tex]volume=\frac{28122.58 g}{0.720\frac{g}{cm^{3} }}[/tex]

volume= 39059.14 cm³= 39059.14 mL= 39.05914 L (being 1 cm³= 1 mL= 0.001 L)

Now, to perform conversion of units from L to qt, you must first know that 1 qt = 0.94635 L. So, if 1 qt is 0.94635 L, how many qt equals 39.05914 L?

[tex]volume= \frac{39.05914 Lx1 qt}{0.94635 L}[/tex]

Solving:

volume= 41.2735 qt

Finally, to perform conversion of units from qt to gal, you must first know that 1 gal = 4.0000 qt. So, if 1 gal is 4 qt, how many gal equals 41.2735 qt?

[tex]volume= \frac{41.2735 qtx1 gal}{4 qt}[/tex]

Solving:

volume= 10.3184 gal

In summary,  if a container is strong enough to hold 62.0 pounds (lb) of gasoline, you can put 10.3184 gallons in there.  

Learn more about density:

The following are the correct decisions;

1) Chemical property

2) Physical property

3) Chemical property

The question is incomplete, the complete question is;

Experiments were done on a certain pure substance X to determine some of its properties. There's a description of each experiment in the table below. In each case, decide whether the property measured was a chemical or physical property of X, if you can. If you don't have enough information to decide, choose can't decide in the third column. property experiment physical or chemical? Х O physical 0 A sample of solid X is carefully weighed and put inside a vented flask. The flask is heated until oxygen gas starts being produced. After no more oxygen gas is produced, the contents of the flask are removed and weighed, and from the decrease in weight the value of O may be calculated. O chemical O (can't decide) O physical V A sample of X is melted and put into a reservoir from which a very thin tube leads down. The rate at which X flows out of the tube is measured, and from this rate the value of V may be calculated. chemical (can't decide) O physical Q A sample of solid X is carefully weighed and put inside a sealed flask. Pure hydrogen gas is added to the flask, and the mixture heated until the hydrogen starts being consumed. After hydrogen stops being consumed, the contents of the flask are removed and weighed, and from the increase in weight the value of may be calculated. O chemical O (can't decide)

A chemical property is one in which atoms of a substances are rearranged in the process. In the first case, the substance was heated and oxygen was produced. This is a decomposition reaction hence it is a chemical property that is being measured.

In the second case, the molten substance is made to flow and the flow rate is measured. The flow rate of a substance is a physical property.

In the third case, hydrogen combines with an element in the flask. This is a chemical property.

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Answer:

AU is homoatomic

Explanation:

Homo-atomic Molecule: Molecules provided by unique one variety of particles are associated as Homo-atomic molecules

Ex: H2, N2, P4 etc.

Hetero-atomic Molecule: Particles constituted by several kinds of atoms are identified as Hetero-atomic molecules

Ex: CO2, NO2, CH4, HCl etc

As AU is homoatomic because this element is formed by only one atom

To learn more about atomic structure refer:

Its option e

Why?

[tex]\\ \sf\longmapsto 0.000354\times 10^4[/tex]

It can be written as

[tex]\\ \sf\longmapsto \dfrac{354}{10000}\times 10^4[/tex]

[tex]\\ \sf\longmapsto \dfrac{354}{10^4}\times 10^4[/tex]

[tex]\\ \sf\longmapsto 354[/tex]

Hence its wrongly written

d is also wrong

[tex]\\ \sf\longmapsto 75.3\times 10^2[/tex]

[tex]\\ \sf\longmapsto \dfrac{753}{10}\times 100[/tex]

[tex]\\ \sf\longmapsto 7530[/tex]

Answer:

2160 days divided by 365 days which is a year is equal to about 5.9 years in school * sighhh*

5.91780821918

Answer:  588.9 lbs

Explanation:  1 lb = 0.454 kg

(267.1kg)*(1 lb/0.454 kg) = 588.9 lbs

Molecular Mass of water:-

[tex]\\ \sf\longmapsto H_2O[/tex]

[tex]\\ \sf\longmapsto 2(1u)+16u[/tex]

[tex]\\ \sf\longmapsto 2u+16u[/tex]

[tex]\\ \sf\longmapsto 18u[/tex]

[tex]\\ \sf\longmapsto 18g[/tex]

1mole of water weighs 18g

We know

[tex]\\ \sf\longmapsto 1mol=6.023\times 10^23molecules[/tex]

Mass of one molecule:-

[tex]\\ \sf\longmapsto \dfrac{18}{6.023\times 10^23}[/tex]

[tex]\\ \sf\longmapsto 2.98\times 10^24g[/tex]

Answer:

A. elements

I hope it's helps you

Answer:

A i think

Explanation:

Answer:

10 ml

Explanation:

The graduated cylinder contains 19 ml of water before the silver pellet is placed inside. Afterwards, the graduated cylinder measures 29 ml of water. Therefore the pellet displaced 10 ml of water. ( 29ml - 19ml = 10ml )

Answer:

1 mol of H2SO4 contains 6.022 x 10^23 molecules. : 0.5 mol of H2SO4 contains 0.5 x 6.022 x 10^23 molecules. = 3.011 x 10^23 molecules . that is 49 g of H2SO4 contains 3.011 x 10^23 molecules of H2SO

Explanation:

The unit that is equivalent to 75g is 0.075 kg, 750 dg, and 7.5 dag. The correct options are b, c, and d.

Measuring units are the units used to denote the measurement quantities. There are seven basic measuring units. They are length, Time, Amount of substance, Electric current, Temperature, Luminous intensity, and Mass.

The current unit is given grams, which are used to measure the mass of any object.

1000 grams is equal to 1 kilogram and 1 dg = 0.1 g, and 1 dag = 10 g. So by this formula, each of the quantities can be calculated.  

1 kg = 1000 g

So, 0.075 kg = (0.075 × 1000)g = 75 g

1 dg = 0.1 g

So, 750 dg = (750 × 0.1) g = 75 g

1 dag = 10 g

So, 7.5 dag = (7.5 × 10) g = 75 g

Thus, the correct options are b. 750 dg, c. 7.5 dag, and d. .075 Kg.

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Answer:

There are many items that could be altered to test the reaction of another. These changing quantities are called variables. A variable is any factor, trait, or condition that can exist in differing amounts or types. An experiment usually has three kinds of variables: independent, dependent, and controlled.

Explanation:

Answer:

3.50 mol x 6.022 x 10^23

= 2.11 x 10^24 carbon atoms

Explanation:

1. moles = grams/molar mass

2. (mass nitrogen/mass amm sulfide)*100 = ??

3. mass Hg = volume x density

Then convert to moles.

Then remember there are 6.022E23 atoms for every mole.

Answer:

desity =mass /volume

27/ 3cube

1g/cm³

eu vou colocar V(verdadeiro) F (falso)

1:F  

2:F

3: V

4:F

explicação:

1 procariontes não apresentam núcleo

2 eles podem sim caso  contrário os seres procariontes não sobreviveriam

3   ele possui organelas celulares

4 as células eucariontes são maiores e mais complexas.

CONCLUSÃO: a resposta certa é a 3

Answer:

some of them not believe in God

Answer:

0

Explanation:

It has no charge.

Salicylic acid is insoluble in water because it is a non-polar covalent compound.

For this reason it is a poor conductor of electricity as it has no free moving ions that would act as charge carriers.

But on the other hand salicylate which is a conjugate base of salicylic acid has a charge of -1 and can be written as C7H5O3-.

hopefully this makes sense

:)

Answer:   In table below.

Explanation:

A.N. (atomic number) = protons

Mass (Total AMU)

Charge

P= Protons, same as atomic number

N = Neutrons, Atomic Mass Number - Protons

E = Electrons.  (Atomic Number - Charge)

Element = Defined by atomic number

a) Atomic number=9   Protons = 9, neutrons = 9, electrons = 10

b) Atomic number=43, Protons = 43, neutrons = 56, electrons = 36

c) Atomic number=53, Protons = 53, neutrons = 78, electrons = 52

d) Atomic number=81,  Protons = 81, neutrons = 120, electrons = 80

e) Name the elements in parts (a), (b), (c), and (d) are F, Tc, I and Tl.

Atomic Number (Z)= number of protons = number of electrons

Mass number (A) = number of protons + number of neutrons.

For ions with a positive net charge:

Number of electrons = Z - net charge

For ions with negative net charge:

Number of electrons = Z + net charge

a) Atomic number=9   Protons = 9, neutrons = 9, electrons = 10

b) Atomic number=43, Protons = 43, neutrons = 56, electrons = 36

c) Atomic number=53, Protons = 53, neutrons = 78, electrons = 52

d) Atomic number=81,  Protons = 81, neutrons = 120, electrons = 80

e) Name the elements in parts (a), (b), (c), and (d) are F, Tc, I and Tl.

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Answer:

There are 1609.344 meters in a mile

Explanation:

Answer:

because mixed particles are visible in this mixture.

Answer:

Oil and water do not mix, instead forming two distinct layer called phase. The oil phase is less dense than the water phase, and so the oil floats on top of the water.

Answer:  0.885 M

Explanation:  19.4 grams of NaCl is (19.4g/58.55 g/mole) = 0.332 moles of NaCl.  375ml is 0.375 liters.  Molar is moles per liter:  (0.332 moles NaCl/0.375 liters) = 0.885 M

Answer:

it would take 2 years

Explanation:

93/55=1.69--->1.70------>2