Which of the following best describes Avogadro's number?*
A) An equation that can be used to calculate how many atoms are in one mole of
anything
B) A variable that represents the value of the atomic mass relative to one mole of an
element
C) A constant that states how many atoms/molecules are in one mole of anything
D)An expression in scientific notation that represents the average atomic mass of an
element

Answer: 300g

Explanation:

first we write the given values on top

224L. x

3 NO2 (g) + H2O (l) = 2HNO3 (l) + NO (g)

22.4L 30g

then we form a formula

224L/22.4L= x/30g

224*30/22.4

6720/22.4= 300g

Answer:

C

Explanation:

C5H12(g) +802(g) - 5CO2(g) + 6H2O(g)

The balanced chemical equation of pentane (C5H12) which reacts with oxygen is

C5H12(g) +802(g) - 5CO2(g) + 6H2O(g)

It is the chemical equation in which the atom or molecules or moles of elements on both side reactant and product.

Our reactants are pentane and oxygen. Since, fourth and sixth reaction do not contain pentane. Therefore, fourth and sixth reaction are wrong.

Now, our next step is to compare product.

As we know that, Carbon dioxide and water are produced when pentane (C5H12) reacts with oxygen. So, we get to the conclusion that carbon dioxide and water are the product.

Since, rest of the equation have carbon dioxide and water as product.

On reactant side, there are 5 carbon atoms and 12 hydrogen atom. So, on product side there must be 5 carbon atoms and 12 hydrogen atom. Now we balance the oxygen atom on both side.

Thus, we concluded that the balanced chemical equation of pentane (C5H12) which reacts with oxygen is

C5H12(g) +802(g) - 5CO2(g) + 6H2O(g).

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Answer:

SOrry it makes me writer sotufjksankdn

Explanation:

Answer:

The heat flow into Earth's atmosphere varies as the Sun rises and sets, gradually increasing during the day and falling to zero at night.

Explanation:

Heat radiates from the ground into the lower atmosphere. In conduction, heat moves from areas of more heat to areas of less heat by direct contact. Warmer molecules vibrate rapidly and collide with other nearby molecules, transferring their energy.

Answer:

Activator effects a mixture if you put to much of the activator your using into a product or thing you are using.

Explanation:

For ex.

If you poor to much activator into slime it will make the slime hard and very wet it will ruin your slime completely so you will have to do it just right but start off pouring it slowly and mix and then more if it needs more.

Answer:

B

Explanation:

There's a three in front of the CH3COOH. But let's figure it out without that 3.

1 mol of CH3COOH has 3 H from CH3 and 1 hydrogen at the end. In all 4 hydrogens.

Now put the 3 in front 3CH3COOH multiplies everything by 3. So you had 4 before and with the 3 in front you must have 12.

Try it. Draw it out.

CH3COOH     has 4

CH3COOH     has 4

CH3COOH     has 4

Total                      12

That's B

Answer:

83.33ml

Explanation:

Firstly, let's notice that 200ml are equal to 0.2L

M=number of moles of the solute ÷ number of liters. Let's call the number of liter by x:

2.5=x÷0.2

x=2.5×0.2

x=0.5

It means you'll need 0.5 mol of HNO. But your solution have 6 moles per liter, so how much do you need? Divide the moles by 12 to have 0.5, so now you need to divide the liter per 12 too. The liter is equal to 1000ml, so:

1000ml÷12=83.33ml

3-ethyl-2.4-dimethyl-octanoic acid

Answer:

Explanation:

The pH of a solution can be found by using the formula

[tex]pH = - log [ { H_3O}^{+}][/tex]

From the question we have

[tex]ph = - log(5.67 \times {10}^{ - 4} ) \\ = 3.2464[/tex]

We have the final answer as

Hope this helps you

From the calculations and the principles of radioactivity, the age of the parent isotope is 144 years

The term radioactivity has to do with the spontaneous decay of a substance.

We know that we have about 25% parent isotope still remaining hence;

[tex]0.693/t1/2 =2.303/t log No/N\\When N =0.25 No and t1/2 = 72 years\\0.693/72 =2.303/t log No/0.25No\\0.0096 = 2.303/t *0.60206\\0.0096 = 1.3865/t\\t = 1.3865/0.0096\\t =144 years[/tex]

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Answer:

A. 144 years old

Explanation:

Answer:

2

H

2

+

O

2

=

2

H

2

O

Explanation:

From the original equation, you first need to write each component separately.

H

2

+

O

2

=

H

2

O

Left side: H = 2 ; O = 2 (number based on the subscript)

Right side: H = 2 ; O = 1 (number based on the subscripts; no subscript means that the element is just 1)

Notice that the number of H is already balance but the number of O is not. In order to balance the O, you need to multiply the element by 2, but you CANNOT do this by simply changing the subscript.

Hence,

H

2

+

O

2

=

2

H

2

O

Left side: H = 2 ; O = 2

Right side: H = 2 x 2 = 4 ; O = 1 x 2 = 2

Now, notice that the number of O is now balance (both are 2) but the number of H is not (since

H

2

O

is a substance and not an element, you need to multiply everything by 2). So, what to do?

You also multiply the left side H by 2. Hence,

2

H

2

+

O

2

=

2

H

2

O

Left side: H = 2 x 2 = 4 ; O = 2

Right side: H = 2 x 2 = 4 ; O = 1 x 2 = 2

The equation is now balanced.

Answer:

Q = 2.60 • [tex]10^{3}[/tex] J

Explanation:

Our specific heat capacity equation is:

Q = mC∆T

Q is the energy in joules.

m is the mass of the substance.

∆T is the temperature chance.

Let's plug in what we know.

Q = 76.0(2.22)(15.4)

Multiply.

Q = 2598.288

We want three significant figures.

Q = 2.60 • [tex]10^{3}[/tex]

or

Q = 2590 J

Hope this helps!

Answer:6,985.008

Explanation:

so the hear formula is mass times specific heat times change in temperature (kelvin) so what i did was got the change in temperature (41.4 K) and multiplied that times 2.22 J/(g•K)and multiplied that by 76 grams of Octane to get the Answer (not in scientific notation)

Answer:

HNO3 & H2SO4

Explanation:

HNO3 is Nitric acid and H2SO4 is Sulphuric acid

Answer:

Cr is oxidised

and

Zn is reduced

[ Reduced reactant ] :

Cr^( + 3 ) + 3 e^( - 1 ) ===》 Cr^( 0 )

_____________________________

[ Oxidicided reactant ] :

Zn^(0) ===》Zn^( + 2 ) + 2 e^( - 1 )

Answer:

506.0 g sodium and 778.8 g chlorine gas

Explanation:

The elements from which sodium chloride (NaCl) is composed are sodium (Na) and chlorine (Cl). Thus, the chemical equation for the production of sodium chloride (NaCl) from sodium (Na) and chlorine gas (Cl₂) is the following:

2Na(s) + Cl₂(g) → 2NaCl(s)

According to the balanced equation, 2 moles of NaCl are produced from 2 moles of Na(s) and 1 mol of Cl₂. To produce 22.0 mol of NaCl, we need:

22.0 mol NaCl x 2 mol Na(s)/2 mol NaCl = 22.0 mol Na(s)

22.0 mol NaCl x 1 mol Cl₂/2 mol NaCl = 11.0 mol Cl₂

Now, we convert the moles of each reactant to grams with the molar mass (MM) of the compound:

MM(Na) = 23 g/mol

22.0 mol Na x 23 g/mol = 506.0 g Na(s)

MM(Cl₂) = 35.4 g/mol x 2 = 70.8 g/mol

11.0 mol Cl₂ x 70.8 g/mol = 778.8 g Cl₂

Therefore, it is required a mass of 506.0 grams of Na(s) and a mass of 778.8 grams of Cl₂ to produce 22.0 mol of NaCl.

Answer: 4.999 moles of excess reactant will be left over.

Explanation:

Limiting reagent is defined as the reagent which is completely consumed in the reaction and limits the formation of the product.

Excess reagent is defined as the reagent which is left behind after the completion of the reaction.

The number of moles is defined as the ratio of the mass of a substance to its molar mass.

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]       .....(1)

Given mass of aluminium carbide = 112 g

Molar mass of aluminium carbide = 143.96 g/mol

Putting values in equation 1:

[tex]\text{Moles of aluminium carbide}=\frac{112g}{143.96g/mol}=0.778mol[/tex]

For the given chemical reaction:

[tex]2Al_4C_3(s)+12H_2O(l)\rightarrow 3CH_4(g)+4Al(OH)_3(s)[/tex]

By the stoichiometry of the reaction:

2 moles of aluminium carbide reacts with 12 moles of water

So, 0.778 moles of aluminium carbide will react with = [tex]\frac{12}{2}\times 0.778=4.668 mol[/tex] of water

Given mass of water = 174 g

Molar mass of water = 18 g/mol

Putting values in equation 1:

[tex]\text{Moles of water}=\frac{174g}{18g/mol}=9.667mol[/tex]

Moles of excess reactant (water) left = 9.667 - 4.668 = 4.999 moles

Hence, 4.999 moles of excess reactant will be left over.

Explanation:

2/1×1.25

=2.5 mole of NaCl are produced

weight of NaCl produced = moles × molar mass of NaCl

weight of NaCl produced = 2.5×58.5

weight of NaCl produced =146.5 grams

Answer:

having a smooth or lubricated surface may help decrease friction.

Explanation:

Answer:

4Cr + __302 -->_2Cr203.....

Answer:

8.73 × 10²⁴ formula units

Explanation:

To calculate the number of formula units a substance contain, we multiply the number of moles by Avagadro number (6.02 × 10²³)

number of formula units = 14.50 moles × 6.02 × 10²³

= 87.29 × 10²³

= 8.73 × 10²⁴ formula units.

Answer:

bismuth

Explanation:

i think if not i am so sorry

Answer:

Molar mass = [9(12.0)+8(1.01)+4(16.0)] = 180.1 g/mol Moles = 112 g 1 mol x 180.1 g = 0.622 mol (3 sig figs)

Explanation:

Answer:

See Explanation

Explanation:

The way by which a metal is obtained from its ore is determined by the chemical reactivity of the metal.

Metals that are highly reactive are chiefly obtained by electrolysis of the metal salt. These metals are found high up in the metal activity series.

Metals that are at the middle of the series are moderately reactive and are obtained by electrolysis or by reduction since they still form ionic salts.

Metals that are far lower in the series can only be obtained by heating them in air because they are mostly unreactive.

Hence, moderately reactive metals at the middle of the series are not obtained by roasting in air.

Answer:

Claim 1

Explanation:

I chose this claim because I believe that when the plates under the earth move or shift, that's what causes an earthquake and when everything starts to shake. If it was the other way around there wouldn't be any reason for an earthquake to start.

hope that helped :)

Answer:

Plates move, which can cause earthquakes.

Explanation:

Tectonic plates are always slowly moving, however sometimes they can "lock" together, creating pressure and build up. The release of this energy results in a Tectonic earthquake. Therefore, the movement of plates causes earthquakes.