Which of the following is true about Avogadro’s number? *

A. It’s 6.02 x 1023 number
B. It’s a counting number
C. It is used to convert between molecules and moles
D. All of the above

Potassium reacts with dilute hydrochloric acid to give potassium chloride and hydrogen gas. Heating small pieces of Potassium in air results in the substance melting without any flame being seen and turning instantly into a mixture of potassium peroxide and potassium super oxide.

A Potassium Reaction involves a process in which Potassium is mixed with another substance which react to form something else. Reactions are manifested by the disappearance of properties characteristic of Potassium and the appearance of new properties in the new substance or Compound.

The substances initially involved in a reaction are called reactants or reagents. The most important of the Potassium compounds is Potassium chloride (KCl) which is used in the production of fertilizers and chemicals and also as a salt substitute. Other important compounds are Potassium nitrate (KNO3), also known as saltpeter which is used in the production of gunpowder, fertilizers and pyrotechnics and Potassium hydroxide (KOH) is used to make detergents and soaps. Reactions are described with Chemical Formula and Equations.

Answer:

gas laws involve the physical laws that describe the properties of gases.

Explanation:

The name of the molecule shown is Ethanol.

Ethanol is a alcoholic substance that is formed from fermentation of glucose in the presence of yeast or microorganisms.

It has a chemical group that have methyl group, hydroxyl group OH which is bonded to carbon atom.

Therefore, The name of the molecule shown is Ethanol.

Learn more about ethanol below.

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Answer:

true

Explanation:

PV=nRT

The ideal gas law states that PV = NkT, where P is the absolute pressure of a gas, V is the volume it occupies, N is the number of atoms and molecules in the gas, and T is its absolute temperature. The constant R is called the Boltzmann constant

Explanation:

Solution is a homogenous mixture of two or more substances in relative amounts that can be varied continuously up to what is called the limit of solubility.

A mixture in which one substance is divided into minute particles (called colloidal particles) and dispersed throughout a second substance

A suspension is a heterogeneous mixture of a finely distributed solid in a liquid. The solid is not dissolved in the liquid, as is the case with a mixture of salt and water.

The question is: What is the boiling point of an aqueous solution of urea at 20% m / m (20g of solute for every 80g of solvent), if the molar mass of urea is 60 g / mol. (Kb = 0.52 ° C / m)

Answer: The boiling point of given aqueous solution of urea is [tex]2.145^{o}C[/tex].

Explanation:

Given: Mass of solute = 20 g

Mass of solvent = 80 g (1 g = 0.001 kg) = 0.08 kg

[tex]K_{b} = 0.52^{o}C/m[/tex]

Molar mass of urea = 60 g

Molality is the number of moles of solute present in a kg of solvent.

Moles is the mass of a substance divided by its molar mass. So, moles of urea is calculated as follows.

[tex]Moles = \frac{mass}{molar mass}\\= \frac{20 g}{60 g/mol}\\= 0.33 mol[/tex]

Now, molality of given solution is as follows.

[tex]Molality = \frac{moles}{mass(in kg)}\\= \frac{0.33 mol}{0.08 kg}\\= 4.125 m[/tex]

Formula used to calculate the boiling point is as follows.

[tex]\Delta T_{b} = K_{b}m\\= 0.52^{o}C/m \times 4.125 m\\= 2.145^{o}C[/tex]

Thus, we can conclude the the boiling point of given aqueous solution of urea is [tex]2.145^{o}C[/tex].

Answer:

elementos original

set onde

Answer:

2(CaSO4)*H2O

Explanation:

To solve this question we need to find the moles water, H2O, of calcium sulfate, CaSO4 as follows:

The molar mass of the anhydrous CaSO4 are 136.14g/mol and the molar mass of the hemihydrate is 145.15g/mol. The differences in molar mass represents the additional mass that water is producing:

145.15g/mol - 136.14g/mol = 9.01g/mol

A 1 mole of water weighs 18.015g/mol, the additional mass of water is due the addition of 1/2 moles of H2O. That means we have 1 mole of CaSO4 per 1/2 mole of H2O. That is the same:

2(CaSO4)*H2O

And this is the formula that gives the correct ratio for the hemihydrate.

Answer:

The oxidation state of N in the KNO3 is +5

Explanation:

Oxidation rules:

1. Oxygen is -2, unless in peroxides.

2. Group 1 metals = +1

3. Group 2 metals = +2

4. If the molecule is neutral, all of the oxidation numbers have to add up to zero.

5. If the molecule is charged, all of the oxidation numbers have to add up to the charge of the molecule.  

So, the given formula represents the salt compound formula unit of potassium nitrate:  KNO3  

The formula unit is uncharged.

From our rules, we know that,

O = -2

And we can find K on the periodic table, in the first group, thus giving it a +1 charge. Now let's put it all together.

K = +1

N = x

O = -2

Let's take into account the number of atoms of each element we have and make an equation since we know everything has to add up to zero since the molecules are neutral.

+1 +x+3 (-2) = 0 (notice we multiplied 3 by -2 because in the formula we have 3 atoms of oxygen with -2 charge each)

x - 5 = 0

x = 5

Therefore, the oxidation number of N in KNO3 is +5.

Answer:

6

Note:

Please check Rasputin020's answer instead of this, It's more detailed.

Answer:

Strong acids react faster whereas weak acids take time to react with any base.

Strong acids are good conductors of electricity on contrary weak acids are not too good as conductors of electricity.

Strong acid passes electricity faster whereas weak acids are slow conductors.

Strong acids are not edible but weak acids are edible.

Strong acids have ph value ranging between 0 to 3 but the ph value of weak acids ranges between 5 to below 7.

Answer:

iii) Figure 2 needs to have one X in the intersection, and one O in the intersection. This is because hydrogen requires 2 electrons in it’s outer shell to become stable. By sharing, both hydrogen atoms can become stable.

c) (i) Universal indicator.

i’m not 100% sure, however i’m quite certain :)

Answer:

Like many common group 2 metal carbonates, magnesium carbonate reacts with aqueous acids to release carbon dioxide and water

 MgCO3 + 2 HCl → MgCl2 + CO2 + H2O.

The procedure to obtain pure magnesium chloride from the reaction is as thus

Step 1: Reaction

- Leave the dilute hydrochloric acid in a beaker.

- Add Magnesium carbonate slowly until it is in excess or until no more gas seem to be getting liberated.

Step 2: Filtration

- Filter with filter paper and funnel.

- Filter off the excess magnesium carbonate as magnesium chloride will be in aqueous form (liquid) and will come out with the filtrate. The residue is the excess magnesium carbonate.

Step 3: Crystallization to obtain solid crystals from the filtrate.

- Pour filtrate solution into evaporating dish/basin

- Provide heat using Bunsen burner

- Pour solution into an evaporating basin and heat over a water bath

- Stop heating when crystals start to form

allow water to evaporate until pure crystals remain.

- Dry crystals using absorbent paper or warm oven.

Precautions

- Use personal protective equipment such as gloves, a lab coat and wear eye protection, especially when heating.

- Avoid inhaling unnecessary gases during the whole process.

Answer:

x = -9, 0 = -1, x \ne 0

Explanation:

[-54/x = 6  0x = 9]

Isolate x for - 54/x = 6 : x = -9

-54/x = 6

Multiply both sides by x

-54/x = 6x

Simplify - 54/x x :  -54

-54x x = 6x

Multiply fractions: a . b/c = a . b/c

= -54x/x

Cancel the common factor: x

= -54

- 54 = 6x

Switch sides

6x = -54

Divide both sides by 6

6x/6 = -54/6

Simplify

6x/6 = -54/6

Simplify 6x/6:  -9

6x/6

Divide the numbers: 6/6 = 1

= x

Simplify

-54/6

Apply the fraction rule: -a/b = -a/b

= -54/6

Divide the numbers: 54/6 = 9

= -9

x = -9

Verify solutions

Find underfined (singularity) point: x = 0

Take the denominator (s) of - 54/x and compare to zero

x = 0

Combine undefined points with solutions:

x = -9

Substitute x = -9

[ o(-9) = 9]

Simplify

0(-9) = 9

Simplify

0(-9): -90

Remove parentheses: (-a) = -a

= -0 . 9

-90 = 9

[-90 = 9]

Isolate o for -90 = 9 : o = -1

-90 = 9

Divide both sides by -9

-90/-9 = 9/-9

Simplify

0 = -1

The solutions to the system of equations are:

x = -9, 0 = -1, x \ne 0

Answer:

С. form chains or rings by bonding to itself and other atoms.

Explanation:

Carbon is an element in group 4 of the periodic table with unique bonding properties. Carbon posseses 4 valence electrons in its outer shell. This enables carbon to form covalent bonds with the atoms of other elements e.g. nitrogen, phosphorus, oxygen, hydrogen etc.

Carbon can also combine covalently with other carbon atoms i.e. C-C to form long chains and rings in a process called CATENATION. This unique property of carbon makes it the only element that can form so many different compounds.

Answer:

20

Explanation:

calculated saturated solutions

Answer:

answer is d on edge

Explanation:

Answer:

0.3549

Explanation:

the percentage yield is the percentage of the product formed based on the theoretical yield.in this question the percentage yield and theoretical yield have been given all that's left is the actual yield.so you use the formula

percentage yield=theoretical yield/actual yield×100

83.4=0.296/ay×100

83.4ay/83.4=100×0.296/83.4

ay=0.3549

I hope this helps

Answer:

Explanation:

we use the ideal has law when a bad changes false

1 CH3-CHBR-CH2BR

2.CH3-CH2-CH3

3.CH3-CHCL-CH2CL

Answer:

"0.583" is the appropriate answer.

Explanation:

Let,

The initial constant of [tex]N_2O_4[/tex] be "C".

Amount of [tex]N_2O_4[/tex] dissociated into [tex]NO_2[/tex] be "x".

now,

                                     [tex]N_2O_4 \rightleftharpoons 2NO_2[/tex]

Initial constant               C            -

Equilibrium constant     C          2x

The Kc is given as:

⇒ [tex]K_c = \frac{[NO_2]^2}{[N_2O_4]}[/tex]

         [tex]=\frac{(2x)^2}{C-x}[/tex]

[tex]0.593=\frac{4x^2}{0.88-x}[/tex]

  [tex]4x^2=0.593(0.88-x)[/tex]

  [tex]4x^2=0.512-0.593\ x[/tex]

     [tex]x=0.291[/tex]

hence,

The constant of [tex]NO_2[/tex] will be:

= [tex]2x[/tex]

= [tex]0.583[/tex]

Answer:

Al is oxidized while Ag is reduced.

Explanation:

The complete molecular equation is;

3Ag2S + 2Al --> 6Ag + Al2S3

Oxidation half equation;

2Al ------> 2Al^3+ + 6e

Reduction half equation;

6Ag^+ + 6e -------> 6Ag

Overall redox reaction equation;

2Al + 6Ag^+ ----->2Al^3+ + 6Ag

Hence; Al is oxidized while Ag is reduced.

Answer:

On a Plateu on a heating curve phase changes are occuring

Explanation:

The first Phase is melting during which the temrature stays the same while water melts.Other phase changes are freezing sublimation Vaourization condensation and deposition

Here, we have been given that;

Hence, we can note that,

(n) = 32.05

[tex] \\ [/tex]

Thus,

Hence, molarity of the given solution will be 32.05 mg/L.

Answer:

B. control rods and moderators