what does it mean to count atoms

Answers

Answer 1

When you count atoms, remember to multiply the coefficient number and the subscript number to find the number of atoms of that element. Examples: ▪ 2H2O. Number of atoms Number of molecules = 2. H-4.


Related Questions

What occurs when a reaction reaches equilibrium?

1)The concentration of the reactants increases.
2)The concentration of the products increases
3)The rate of the forward reaction is equal to the rate of the reverse reaction
4)The rate of the forward reaction is slower that the rate of the reverse reaction.

Answers

Answer:

3)The rate of the forward reaction is equal to the rate of the reverse reaction

Answer:

The Rate of Forward Reaction is equal to the rate of the reverse reaction.

Explanation:

Hope this helps :)

1. For each of the following formulas:
1) if ionic, write the formulas of the ions; if covalent, draw the Lewis structure
2) For each covalent compound, describe the electronic and molecular geometry
3) For each covalent compound, describe the hybridization of the central atom
4) Name each compound, except the organic one.
5) How many sigma and how many pi bonds does each compound have?
MnSO4 CH3NH2 PCl5 O2 LiF

Answers

Answer:

See Explanation

Explanation:

The ionic compounds are; MnSO4 and LiF

The covalent compounds are; CH3NH2, PCl5 and O2

1) The formulas of the ions are;

MnSO4  - Mn^2+ SO4^2-

LiF - Li^+ F^-

The structure of each of the three covalent molecules is shown in the images attached to this answer.

2) CH3NH2 - Has a tetrahedral molecular geometry and electronic geometry

PCl5 - Has a trigonal bipyramidal molecular geometry and electronic geometry

O2 - Has a linear molecular geometry and electronic geometry.

3) CH3NH2  is sp3 hybridized

PCl5 is sp3d hybridized

O2 - is sp2 hybridized

4) MnSO4  - Manganese  II sulphate

PCl5 - Phosphorus pentachloride

O2 - Oxygen molecule

LiF- Lithium fluoride

5) PCl5 - Five sigma bonds and no pi bond

CH3NH2 - 6 sigma bonds and no pi bond

O2 - 1 sigma bond and 1 pi bond

Considering the temperature vs. time graph below, how does the temperature at the beginning of a change of state compare with the temperature at the end of the change?

- The temperature is always lower.
- The temperature is always the same.
- The temperature is usually lowest
- The temperature is usually higher.​

Answers

The temperature at the beginning and the end of a change of state correct option is : The temperature is usually the same.

When looking at a temperature vs. time graph during a change of state, such as melting or boiling, the temperature remains constant throughout the duration of the change. This is because during a change of state, the heat energy is used to break the intermolecular bonds rather than increase the temperature. As a result, the temperature remains constant until the entire substance has completed the phase transition.At the beginning of the change of state, the substance is at its melting or boiling point, and the temperature remains constant as the substance absorbs heat energy to transition from a solid to a liquid (melting) or from a liquid to a gas (boiling). At the end of the change of state, the substance has fully transitioned, and the temperature remains constant until all the substance has completely melted or boiled.

The correct option is: The temperature is usually the same.

For more such questions on temperature

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The temperature at the beginning of a change is always lower than the temperature at the end of the change option A

Does the temperature increase as the phase change progresses?

The temperature doesn't vary during a phase transition, such as melting or boiling, until the phase change is finished. This is so that intermolecular forces can be broken rather than the average kinetic energy of the particles, which is related to temperature, being increased by the heat energy being applied to the substance.

But the temperature does increase from one point to the other on the heating curve.

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[H+] [OH-] =

NEED HELP ASAP!!!

Answers

Hopes this helps:

Answer: h^2o

If this doesn’t help than I am so sorry that I couldn’t help.

PLEASE HELP!! ORGANIC CHEMISTRY

A sample of a diatonic gas is loaded into an evacuated bottle at STP. The 0.25 L bottle contains 1.76 grams of the unidentified gas. Calculate the molar mass of the gas. What is the identity of the diatomic gas?

Answers

Answer:

(a) 157.7 g

(b) 7.04 g/dm³

Explanation:

(a) From the question,

According to Avogadro's Law,

1 mole of every gas at STP occupies a volume of 22.4 dm³

But mass of 1 mole of the diatomic gas  = molar mass of the gas.

This Implies that,

The molar mass of the gas at STP occupies a volume of 22.4 dm³

From the question,

If,

0.25 L bottle contain 1.76 g of the gas,

Therefore,

Molar mass of the gas = (1.76×22.4)/0.25

Molar mass of the gas = 157.7 g.

(b) Density of the gas = mass/volume

D = m/v

Given: m = 1.76 g, v = 0.25 L = 0.25 dm³

Therefore,

D = 1.76/0,25

D = 7.04 g/dm³

Consider the aldol-dehydration reaction. Draw the two possible products of the reaction between benzaldehyde and methylethylketone. (Do not draw the products of the double-condensation.)

Answers

Solution :

An [tex]$\text{aldol condensation}$[/tex] reaction is a type of [tex]\text{condensation reaction}[/tex] in organic chemistry where the enol or an enolate ion reacts with the carbonyl compound and forms a [tex]$\beta$[/tex]-hydroxyaldehyde or a [tex]$\beta$[/tex]-hydroxyketone, and then followed by a dehydration to give conjugated enone.  

Benzaldehyde reacts with methylketone and forms two products:  

HCN
H:C:N:
3.
Is this Lewis Structure correct?

Answers

Answer:

No, your missing some bonds

8
What happens to solid waste in the circulatory system?
A it's expelled through the lungs
B
It pumps into the coronary circulation
C
It's dropped off in the kidneys
D
It's deposited in the aorta

Answers

Answer:c it’s dropped off in the kidneys

Explanation:

I took the quiz

The solid wastes are from the circulatory system is expelled to the kidney where, the nitrogenous wastes like urea and uric acid is excreted as urine from the body.

What is circulatory system ?

A circulatory system is an organ system, where the blood is purified and oxygenation of blood takes place. Through circulatory system, the blood reaches throughout the body pumped from the heart through veins.

The organs included in circulatory system are lungs, heart, aorta, veins, blood vessels etc. There are various kinds of blood vessels each having specific functions.

There is a network of blood vessels including arteries and large veins, capillaries that join the venules and other veins. All the nutrients and ions are circulated throughout the body through blood and solid wastes are then expelled to kidney.

Kidney function as a sieve to clean the good fluid from waste products. Uric acid and urea along with water excreated as urine then. Thus, option C is correct.

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At 27.0°C, the volume of a gas is 630 L. At the same pressure, its volume is 92,0 mL at a temperature of

Answers

Answer:

–272.96 °C

Explanation:

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

Initial temperature (T₁) = 27.0 °C

Initial volume (V₁) = 630 L.

Final volume (V₂) = 92.0 mL

Final temperature (T₂) =?

Next, we shall convert 27.0 °C to Kelvin temperature. This can be obtained as follow:

T(K) = T(°C) + 273

Initial temperature (T₁) = 27.0 °C

Initial temperature (T₁) = 27.0 °C + 273

Initial temperature (T₁) = 300 K

Next, we shall convert 92.0 mL to L. This can be obtained as follow:

1000 mL = 1 L

Therefore,

92 mL = 92 mL × 1 L / 1000 mL

92 mL = 0.092 L

Next, we shall determine the final temperature.

Initial temperature (T₁) = 300 K

Initial volume (V₁) = 630 L.

Final volume (V₂) = 0.092 L

Final temperature (T₂) =?

V₁ / T₁ = V₂ / T₂

630 / 300 = 0.092 / T₂

2.1 = 0.092 / T₂

Cross multiply

2.1 × T₂ = 0.092

Divide both side by 2.1

T₂ = 0.092 / 2.1

T₂ = 0.04 K

Finally, we shall convert 0.04 K to celsius temperature. This can be obtained as follow:

T(°C) = T(K) – 273

Final temperature (T₂) = 0.04 K

Final temperature (T₂) = 0.04 – 273

Final temperature (T₂) = –272.96 °C

Calculate the molarity of the two solutions.
The first solution contains 0.200 mol of NaOH in 2.00 L of solution.
The second is 15.5G of NaCl in 671mL of solution

Answers

Answer:

a) 0.100 M

b) 0.395 M

Explanation:

a) Calculate the molarity of a solution that contains 0.200 moles of NaOH (solute) in 2.00 L of solution

We will use the following expression for molarity.

[NaOH] = moles of solute / liters of solution

[NaOH] = 0.200 mol/2.00 L = 0.100 M

b) Calculate the molarity for a solution that contains 15.5 g of NaCl (solute, 58.44 g/mol) in 671 mL of solution

We will use the following expression for molarity.

[NaCl] = mass of solute / molar mass of solute × liters of solution

[NaCl] = 15.5 g / 58.44 g/mol × 0.671 L = 0.395 M

what is the partial pressure of each gas in a 26L container at 27°c that holds 5 moles of carbon dioxide,3.3 moles of nitrogen and 1.5 moles of hydrogen, and has a total pressure of 1.05

Answers

Answer:

pCO₂ = 0.54 atm

pN₂ = 0.35 atm

pH₂ = 0.16 atm

Explanation:

Step 1: Calculate the total number of gaseous moles

The total number of gaseous moles (n) is equal to the sum of the moles of the individual gases.

n = nCO₂ + nN₂ + nH₂ = 5 mol + 3.3 mol + 1.5 mol = 9.8 mol

Step 2: Calculate the partial pressure of each gas

We will use the following expression.

pi = P × χi

where,

pi: partial pressure of the gas i

P: total pressure (1.05 atm)

χi: mole fraction of the gas i

pCO₂ = 1.05 atm × (5 mol/9.8 mol) = 0.54 atm

pN₂ = 1.05 atm × (3.3 mol/9.8 mol) = 0.35 atm

pH₂ = 1.05 atm × (1.5 mol/9.8 mol) = 0.16 atm

_HCN+_CUSO4=_CUSO4+_CU(CN)2​

Answers

2HCN + CuSO4 → H2SO4 + Cu(CN)2
The answer would be :

[0]HCN + CuSO4 = CuSO4 + [0]Cu(CN)2

Thus is because the left-hand side contain Hydrogen, whereas the right-hand side does not. To balance an equation, an element cannot be added. And therefore, Hydrogen must be removed completely, along with Carbon and Nitrogen, as they each formed a chemical bond with hydrogen, and the composition would change if so.

Explanation chemically :

HCN + CuSO4 = CuSO4 + Cu(CN)2

Left-hand side :

1 H
1 C
1 N
1 Cu
1 S
4 O

Right-hand side :

0 H
1 Cu
1 S
4 O
1 Cu
2 C
2 N

Comparison between the two sides :

First:

1 H = 0 H (therefore to balance it, times the left hand side by 0 : (0)(1) H = 0 H = 0 H)

Because we're multiplying the left-hand side hydrogen atom by 0, and it is bonded with Carbon and Nitrogen, Carbon and Nitrogen is multiplied by 0 as well.

(0) H x (0) C x (0) N = (0) HCN = 0

Hydrogen is balanced.

Second :

Left-hand side Carbon and Nitrogen is 0 (0HCN).
Therefore, right-hand side Carbon and Nitrogen must also be 0.

Cu(CN)2

0 should be multiplied to the CN bracket to bring them to 0. However, there is a Cu atom in from of the CN molecule. So the 0 would be placed in front of the Cu atom, like this :

(0) Cu(CN)2.

The 0 in front of the Cu atom ensures that all the atoms will be multiplied by 0

(0 Cu(CN)2 = (0) Cu x (0) (CN)2 = 0

Carbon and Nitrogen are balanced.

Third :

CuSO4 is already balanced as both sides have an equal amount of each atom.

Therefore, the answer is [0] HCN + [1] CuSO4 = [1] CuSO4 + [0] Cu(CN)2




Is This An Igneous Rock Or Metamorphic Or Sedimentary?

Answers

Answer:

Metamorphic

Explanation:

Answer: thats metamorphic rock

A compound is 70.0% iron and 30.0% oxygen. Its molecular mass is 479.1 g/mol. Determine the
molecular formula.

Answers

Answer:

[tex]Fe_6O_9[/tex]

Explanation:

Hello there!

In this case, since these problems about formulas, firstly require the determination of the empirical formula, assuming that the given percentages are masses, we can calculate the moles and mole ratio of oxygen to iron as shown below:

[tex]n_{Fe}=70/55.85=1.25\\\\n_O=30/16=1.875[/tex]

In such a way, by rounding to the first whole number we multiply by 8 and divide by 5 to obtain:

[tex]Fe_{2}O_{3}[/tex]

Whose molar mass is 159.69 g/mol and the mole ratio of the molecular to the empirical formula is:

479.1/159.69=3

Therefore, the molecular formulais:

[tex]Fe_6O_9[/tex]

Regards!

4. The device shown is a
that's used to measure the heat transferred by a reaction under constant volume.
A. bomb calorimeter
B. reaction vessel
C. thermometer
D. coffee-cup calorimeter

Answers

Answer:

The device shown is a calorimeter that used to measure the heat transfer by a reaction under constant volume.

Explanation:

What is the limiting reactant in the following equation? How much Fe2O3 will be produced if 2.1 g of Fe reacts with 2.1 g of O2?

4 Fe + 3O2 —> 2Fe2O3

Answers

Answer:

Fe is limiting reactant and 3.00g of Fe2O3 will be produced

Explanation:

To solve this question we must convert the mass of each reactant to moles and, using the reaction we can find limiting reactant. With moles of limiting reactant we can find moles of Fe2O3 and its mass as follows:

Moles Fe -Molar mass: 55.845g/mol-

2.1g * (1mol / 55.845g) = 0.0376 moles

Moles O2 -Molar mass: 32g/mol-

2.1g * (1mol / 32g) = 0.0656 moles

For a complete reaction of 0.0656 moles of O2 are needed:

0.0656moles O2 * (4mol Fe / 3 mol O2) = 0.0875 moles Fe

As there are just 0.0376 moles,

Fe is limiting reactant

The mass of Fe2O3 is:

Moles:

0.0376 moles Fe* (2mol Fe2O3 / 4mol Fe) = 0.0188 moles Fe2O3

Mass:

0.0188 moles Fe2O3 * (159.69g / mol) =

3.00g of Fe2O3 will be produced

Study the reaction.
CH4 + 2O2 → CO2 + 2H2O
If 7.4 moles of carbon dioxide (CO2) form at the end of the reaction, how many moles of methane (CH4) and oxygen gas (O2) entered the reaction?

? moles of methane and
? moles of oxygen gas

Answers

7.4 moles of methane (CH₄)

14.8 moles of oxygen gas (O₂)

If 3.13 mol of an ideal gas has a pressure of 2.33 atm and a volume of 72.31 L, what is the temperature of the sample in degrees Celsius?

Answers

Answer:

382.49 C degree Celsius

Explanation:

Hello,

This problem deals with understanding the ideal gas law which hopes to predict how ideal gases might behave in any given condition. I listed the formula below and we are basically just going to solve for temperature by rearranging the equation as seen on the picture (there's also other rearranged ones in case you need to solve for those).

Universal gas constant R has a value of 0.0821 L * atm/(mole * K) when working with these given units so it will be part of this equation. R value changes based on what units you have.

T = PV/nR

   = (2.33) (72.31) / (3.13)(0.0821)

   = 655.64 K

Question is asking temperature in celsius so we employ the formula attached below:

C = K - 273.15

   = 655.64-273.15

    = 382.49 degree Celsius

382.49 degree Celsius is the answer!

UV light can damage biological molecules because it has sufficient energy to break bonds within molecules. A carbon-carbon single bond typically requires 348 kJ/mol of energy to break it. What is the longest wavelength of light with energy sufficient to break this bond

Answers

Answer:

5.72 × 10⁻³¹ m

Explanation:

Step 1: Given and required data

Energy to break 1 mole of C-C single bonds (E): 348 kJPlanck's constant (h): 6.63 × 10⁻³⁴ J.sSpeed of light (c): 3.00 × 10⁸ m/s

Step 2: Calculate the longest wavelength of light (λ) with energy sufficient to break this bond

We will use the Planck-Einstein relation.

E = h × c/λ

λ = h × c/E

λ = (6.63 × 10⁻³⁴ J.s) × (3.00 × 10⁸ m/s)/(348 × 10³ J) = 5.72 × 10⁻³¹ m

Do u believe that you are beautiful/handsome?


Yes or No?

Answers

i think i’m beautiful some days but other days no. Mainly only depends on my mood.

A 251 ml sample of 0.45M HCl is added to 455 mL of distilled water. What is the molarity of the
final solution?

Answers

We are given:

251 mL sample of 0.45M HCl added to 455 mL distilled water

Whack a mole! (finding the number of moles):

We know that in order to find molarity, we use the formula:

Molarity = number of moles / Volume (in L)

so, number of moles is:

Number of moles = Molarity * Volume(in L)

now let's plug the values for the HCl solution to find the number of moles

Number of moles = 0.45M * 0.251 L

Number of moles = 0.113 moles

Time to concentrate (finding the final concentration):

Total final volume = 251 mL + 455 mL = 706 mL = 0.706 L

Number of moles of HCl = 0.113 moles

Molarity = Number of moles / Volume (in L)

Molarity = 0.113 / 0.706

Molarity = 0.16 M

___________________________________________________________

BONUS METHOD TIME!!!

We know the relation:

M1 * V1 = M2 * V2

where M1 and M2 are the initial and final molarities and V1 and V2 are initial and final volumes respectively

notice that I didn't mention that the volume has to be in Liters, that's because of the units being concerned with both sides of the equation, say I have the volume in mL and want to convert both these volumes to L, I would divide both sides by 1000, which would NOT change the overall value

Now, plugging values in this equation

(0.45) * (251) = (251 + 455)* (M2)

112.95 = (706)(M2)

M2 = 112.97/706                                [dividing both sides by 706]

M2 = 0.16 Molar

Draw the major organic product in the reaction scheme. Be sure to clearly show stereochemistry (if applicable). The starting material is an alkyne where carbon 1 is bonded to cyclopentane and carbon 2 is bonded to H. Step 1 is N a N H 2. Step 2 is C H 3 I. Step 3 is sodium in liquid ammonia. Draw the major organic product.

Answers

Answer:

See answer below

Explanation:

The picture below will show you the final product and mechanism.

In the first step, the NaNH₂ is a strong base, so, this base will substract the hydrogen from carbon 2, to generate a negative charge there, and then, carbon 2 becomes a nucleophyle.

As a nucleophyle it will attack to the CH₃I in the next step, and it will attach to the CH₃.

The second step is just a regular step to reduce the triple bond of the alkyne to alkane or alkene, this will depend on the quantity of the reactant. In this case, an alkene.

Hope this helps,,,,,,k

What is the source of energy in nuclear weapons?
A. Combustion
B. Gravity
C. Fusion
D. Fission

Answers

gravity!!!!!!!!!!!!!!!!!!!!!!!

The cation that has the same number of electrons (isoelectronic) as Ne is
None of the listed options
O Na
Mg 2-
All of the listed options
O AI 3-

Answers

Ne is isoelectronic with Na+ ion.

If the pH of a solution is 6.96, then the solution is a

Answers

Answer:

acid

Explanation:

solution with pH less than 7 is acid

those with more that 7 is base

those equal to 7  is neutral

A bottle labeled 0.01 M HCl is found in the laboratory. Assuming that the HCl is completely ionized calculate the [H+], [OH-] and the pH of the solution. ​

Answers

Answer:

[H⁺] = 0.01 M[OH⁻] = 1x10⁻¹² MpH = 2

Explanation:

The assumption that the HCl is completely ionized means that the original concentration of the acid is equal to [H⁺].

[H⁺] = 0.01 M

With [H⁺], we can calculate [OH⁻], by using the following formula:

[H⁺] * [OH⁻] = 10⁻¹⁴0.01 M * [OH⁻] = 10⁻¹⁴[OH⁻] = 1x10⁻¹² M

Finally we calculate the pH of the solution:

pH = -log[H⁺]pH = 2

Which of the following substances can be dissolved in pure water to give a basic solution?

Hydrogen chloride

Sodium bromide

Sodium hydroxide

Sodium chloride

Answers

Maybe the 2nd one??? Not sure

I think it's sodium hydroxide

Explanation:

sodium hydroxide is a base

What is the molarity of a 750.0 milliliter solution containing 2.5 moles of solute?
ОА.
1.9 M
OB
0.0033 M
O c.
1,875 M
OD.
0.30 M
OE.
3.3 M

Answers

Molarity : It is defined as the number of moles of solute present in one liter of solution.

Therefore, the molarity of solution is 3.33

Answer:

A.  1.9 M

B.  0.0033 M

C.  1,875 M

D.  0.30 M

E. 3.3 M

Ice melts after adding heat. The free energy is ————— !

A. Exothermic
B. Not temperature dependent
C. Temperature dependent
D. Depended on how it is heated
E. React with active metals to form h2 gas
F. Endothermic

Answers

Answer: F. Endothermic…………………

Determine the hydroxide ion concentration in
a solution that is 0.00034 M Ca(OH)2.
Answer in units of M.

Answers

Answer:

[tex]0.00068M[/tex]

Explanation:

Hello there!

In this case, according to the ionization of calcium hydroxide, a strong base:

[tex]Ca(OH)_2\rightarrow Ca^{2+}+2OH^-[/tex]

Thus, since there is a 1:2 mole ratio of calcium hydroxide to hydroxide ions, we apply the following proportional factor to obtain:

[tex]0.00034\frac{molCa(OH)_2}{L}*\frac{2molOH^-}{1molCa(OH)_2} \\\\=0.00068\frac{OH^-}{L}\\\\=0.00068M[/tex]

Regards!

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