PLEASE HELP!!!! How many moles of helium are needed to fill a balloon to a volume of 4.9 at 296°K and 0.78 atm?

Answer:Free radical mono-halogenation of an alkane is typically conducted using bromine versus chlorine because the bromine radical is less reactive and therefore more selective.

Explanation: Halogenation occurs when a halogen replaces  one or more hydrogen atoms in an organic compound ie  chlorine or  bromine with the reactivity of the halogens decreasing  in the order of  F2 > Cl2 > Br2 > I2

Since fluorine reacts  explosively making it is difficult to control, and iodine is unreactive. Free radical mono-halogenation of an alkane is typically conducted using bromine versus chlorine  with Chlorination  ie chlorine radical being more reactive and not selective and the Bromination of alkanes ie bromine radical  occurring similarly but slower and less reactive but  more selective which is due to the fact that a bromine atom is less reactive in  the hydrogen abstraction  than a chlorine atom evidence in the  higher bond energy of H-Cl than H-Br.

Answer:

the tail

Explanation:

Answer:

A.) tails

Explanation:

Answer:

The type of music each plant listens to.

Explanation:

A variable is any factor or condition whose value is changing in an experiment. A variable can occur in different types or quantity, and three types of variable (independent, dependent, and controlled) can be found in an experiment. In the experiment described above, "the type of music each plant listens to" is the variable. It is an independent variable whose value is changing because it exists in different types and it is the one that the student is observing its effect on the plant’s growth. In this experiment, this variable which differ will also produce different results (or effects).

Answer:

Check the explanation

Explanation:

1)

Atomic number of Se = 34

So, number of proton = 34

use:

charge = number of proton - number of electron

-2 = 34 - number of electron

number of electron = 36

number of neutron = mass number - atomic number

= 78 - 34

= 44

Answer:

44

34

36

2)

number of proton = mass number - number of neutron

= 65 - 36

= 29

29 is atomic number for Cu

use:

charge = number of proton - number of electron

+1 = 29 - number of electron

number of electron = 28

Answer:

Cu

29

28

3)

Atomic number is 36 for Kr

use:

charge = number of proton - number of electron

= 36 - 36

= 0

use:

mass number = number of proton + number of neutron

= 36 + 42

= 78

Answer:

Kr

78

0

Answer:

127 grams of carbon dioxide

Explanation:

We need to determine the chemical equation first. Butane has a chemical formula of [tex]C_4H_{10}[/tex], oxygen is [tex]O_2[/tex], carbon dioxide is [tex]CO_2[/tex], and water is [tex]H_2O[/tex]. The reactants are butane and oxygen and the products are carbon dioxide and water. So we write:

[tex]C_4H_{10}+O_2[/tex] ⇒ [tex]CO_2+H_2O[/tex]

But remember! We need to balance this. Currently, there are 4 carbon atoms (C), 10 hydrogen atoms (H), and 2 oxygen atoms (O) on the left, while there are 1 carbon atom (C), 2 hydrogen atoms (H), and 3 oxygen atoms (O) on the right. Let's place a coefficient of 4 in front of the carbon dioxide and a coefficient of 5 on the water, so that we have equal numbers of carbon and hydrogen atoms on each side:

[tex]C_4H_{10}+O_2[/tex] ⇒ [tex]4CO_2+5H_2O[/tex]

However, we need to ensure that there are equal numbers of O atoms, as well. On the left, we have 2 and on the right we have 13, so let's put a coefficient of 6.5 on the oxygen:

[tex]C_4H_{10}+6.5O_2[/tex] ⇒ [tex]4CO_2+5H_2O[/tex]

Finally, multiply everything by 2 to get whole number coefficients:

[tex]2C_4H_{10}+13O_2[/tex] ⇒ [tex]8CO_2+10H_2O[/tex]

Ah, now we can actually get to the problem!

We need to determine the limiting reactant, so let's convert the 42 g of butane and 150 g of oxygen into moles of any product, say, carbon dioxide. To convert to moles, we need to find the molar mass of each compound.

The molar mass of butane is 4 * 12.01 + 10 * 1.01 = 58.14 g/mol, while the molar mass of oxygen is 2 * 16 = 32 g/mol. We can now set up the equations:

[tex]42 gC_4H_{10}*\frac{1molC_4H_{10}}{58.14gC_4H_{10}} *\frac{8molCO_2}{2molC_4H_{10}} =2.8896molCO_2[/tex]

[tex]150 gO_2*\frac{1molO_2}{32gO_2} *\frac{8molCO_2}{13molO_2} =2.8846molCO_2[/tex]

Clearly, we see that 2.8846 < 2.8896, which means that oxygen is the limiting reactant. In other words, the most products can be made when the oxygen is all used up.

Now let's finally convert moles of carbon dioxide into grams by multiplying by its molar mass, which is 12.01 + 2 * 16 = 44.01 g/mol:

[tex]2.8846molCO_2*\frac{44.01gCO_2}{1molCO_2} =127gCO_2[/tex]

Notice that we have 3 significant figures because we had 3 significant figures at the start with 150. grams of oxygen.

~ an aesthetics lover

Answer:

The answer you are looking for is A

Answer:The answer to this question comes from experiments done by the scientist Robert Boyle in an effort to improve air pumps. In the 1600's, Boyle measured the volumes of gases at different pressures. Boyle found that when the pressure of gas at a constant temperature is increased, the volume of the gas decreases. when the pressure of gas is decreased, the volume increases. this relationship between pressure and volume is called Boyle's law.

Explanation: So, at constant temperature, the answer to your answer is: the volume decreases in the same ratio as the ratio of pressure increases.

BUT, in general, there is not a single answer to your question. It depend by the context.

For example, if you put the gas in a rigid steel tank (volume is constant), you can heat the gas, so provoking a pressure increase. But you won't get any change in volume.

Or, if you heat the gas in a partially elastic vessel (as a tire or a soccer ball) you will get both an increase of volume AND an increase of pressure.

FINALLY if you inflate a bubblegum ball, the volume will be increased without any change in pressure and temperature, because you have increased the NUMBER of molecules in the balloon.

There are many other ways to change volume and pressure of a gas that are different from the Boyle experiment.

Answer:

D

Explanation:

No energy is lost during transforming into another because energy cannot be reated or destroyed

Answer:

i think is d

Explanation:

I'm not sure wait for a few more answers

Answer:

Metamorphic rocks are formed from pre-existing rock and sediment materials. They are formed when igneous, sedimentary, or other pre-existing metamorphic rocks are exposed to the heat and pressure as well as super-heated mineral-rich fluids. They are compacted together to form a new rock altogether. Metamorphism does not include the melting or liquefaction of the pre-existing rock. Instead, it compacts them and crushes them, pushing them together at extreme heat and pressure to form a new rock altogether composed of sedimentary, igneous, and other metamorphic rock. It's the rock hybrid of the geologic world.

Metamorphism is similar to when you squish playdough together, it doesn't form a new playdough color (unless you REALLY mixed that poor playdough together). It forms an amalgamation of different colors and patterns made from the other rock.

Taken from a paper I once wrote I explained this again:

"Metamorphic rocks are formed when pre-existing rocks and their minerals are compressed and altered by Earth’s internal processes; interior pressure, temperature (heat), and chemical reactions. The minerals and pre-existing rock necessary for the creation of metamorphic rock must then also be located deep underground if such processes are expected to make an impact and create a metamorphic rock."

Answer:

See explaination

Explanation:

Balanced net ionic reaction.

Pb(s) + Cl2(g) ----- Pb2+ + 2Cl-

oxidation reaction :Pb(s) --- Pb2+ + 2e-

Reduction reaction:Cl2 + 2e- -----Cl-

Explanation:

Evaluate the results, letter B

Answer:

It's probably claim 3

Explanation:

It's not claim 1 because the amount of energy from the sun can't change and claim 2 doesn't really make sense.

Answer:

The correct answer is 7.8 percent.

Explanation:

As mentioned in the given question, the absorbance (A) of the sample solution is 1.07. To find the concentration of aspirin, Beer's law is used, that is, A = ebc

Here, e is the extinction coefficient, which is equal to 139.322 M^-1cm^-1 as per the standard value for salicylic acid, b is the pathlength, which is equivalent to 1 cm. Now putting the values we get,  

A = ebc

c = A / (eb)

c = 1.07 / (139.322 × 1)

c = 0.00768 M

Now to determine the percent salicylic acid in the sample, there is a need to compare the value of concentration determined with the concentration of aspirin given initially.  

0.02 grams is the initial concentration of aspirin mentioned in the question. The molar mass of aspirin is 240 g/mol.  

Therefore, the moles of aspirin will be,  

0.02 / 240 = 8.33 × 10^-5 moles  

The final volume of the diluted solution given is 10 ml or 0.01 liters.  

The molarity of aspirin in the diluted solution will be,  

c1 = 8.33 × 10^-5 / 0.01 = 8.33 × 10^-3 M or 0.00833 M

Now, the percent of salicylic acid in the product will be,  

c1 - c / c1 × 100

(0.00833 - 0.00768) / 0.00833 × 100 = 7.8 %

Absorbance is directly proportional to the concentration of the solution. The absorbance can be calculated if the molar absorptivity, path length, and concentration of the absorbing species are known.

The percent of salicylic acid in the solution is 7.8%

Given that:

Absorbance of the solution is = 1.07

Path length = 1 cm.

Applying Beer's Law,

A = ε b c

where,

c = concentration, A = absorbance, ε = constant, and b = path length

Now, putting the values in above equation

c = [tex]\dfrac{\text{A}}{\text {(e b)}}[/tex]

c = [tex]\dfrac{1.07}{139.32 \times 1}[/tex]        ( ε = 139.32)

c = 0.00768 M

Now, to calculate the percent of the salicylic acid in the solution, we will compare the given concentration of the aspirin.

As we know:

Given mass of aspirin = 0.02 g

Molar mass of aspririn = 240

Number of moles of aspirin = 0.02 / 240 = 8.33 x 10⁻⁵

Now, the molarity of aspirin is:

[tex]\text{Molarity}&= \dfrac{8.33 \times 10^{-5}}{0.01}\\\\\text{Molarity}&= 8.33 \times 10^{-5}[/tex]

Now, the percent of the salicylic acid is:

[tex]\dfrac{\text {C}_1 - \text C}{\text {C}_1 \times 100}[/tex]

[tex]\dfrac{(0.00833 - 0.00768)}{0.00833 \times 100}[/tex]

Percent of Salicyclic acid = 7.8%.

Thus, the percentage of the salicylic acid in the given solution is 7.8%.

To know more about Absorbance, refer to the following link:

https://brainly.com/question/17062521

Answer:

[tex]m_{nitrogen}=14g[/tex]

Explanation:

Hello,

In this case, since we are talking about a chemical reaction in which a compound having nitrogen and chlorine is decomposed into chlorine and nitrogen, we must remember that the law of conservation of mass must be obeyed, for that reason, we notice that the mass of the whole reactants must equal the mass of the whole products, as shown below:

[tex]m_{reactants}=m_{products}[/tex]

Next, we know there is only one single reactant and products are constituted by both chlorine and nitrogen:

[tex]m_{reactant}=m_{chlorine}+m_{nitrogen}[/tex]

In such a way, we can compute the mass of nitrogen as shown below:

[tex]m_{nitrogen}=m_{reactant}-m_{chlorine}=120.4g-106.4g\\\\m_{nitrogen}=14g[/tex]

Best regards.

Answer:

A) 84 mL

Explanation:

use general gas equation P1×V1 / T1 = P2×V2/T2

rearrange the formula and solve for V2,it should give you V2= 84mL

Answer:

[tex]\large \boxed{\text{B) 84 mL}}[/tex]

Explanation:

We can use the Combined Gas Laws to solve this problem .

[tex]\dfrac{p_{1}V_{1} }{T_{1}} = \dfrac{p_{2}V_{2}}{T_{2}}[/tex]

Data

p₁ = 0.75 atm; V₁ = 120.0 mL; T₁ = 295 K  

p₂ = 1.25 atm; V₂ = ?;              T₂ = 345 K

Calculations

[tex]\begin{array}{rcl}\dfrac{p_{1}V_{1} }{T_{1}} & = & \dfrac{p_{2}V_{2}}{T_{2}}\\\\\dfrac{\text{0.75 atm $\times$ 120.0 mL}}{\text{295 K}} & = & \dfrac{\text{1.25 atm} \times V_{2}}{\text{345 K}}\\\\\text{0.305 mL} & = & \text{0.003 523V}_{2}\\V_{2}& =& \dfrac{\text{0.305 mL}}{0.003523}\\\\& = & \textbf{84 mL}\\\end{array}\\\text{The new volume of the gas is $\large \boxed{\textbf{84 mL}}$}[/tex]

Answer:

pH=10.88

Explanation:

Hello,

In this case, since potassium hydroxide is completely dissociated as shown below:

[tex]KOH\rightarrow K^++OH^-[/tex]

For which we understand it is a base, more specifically, a strong base; it means that the concentration of the OH⁻ equals the concentration of the potassium hydroxide, that is 0.000765M, for that reason we can directly compute the pOH:

[tex]pOH=-log([OH^-])=-log(0.000765)=3.12[/tex]

Finally, since the pOH and the pH are related by:

[tex]pOH+pH=14[/tex]

The pH turns out:

[tex]pH=14-3.12\\pH=10.88[/tex]

Best regards.

Answer:

See explanation below

Explanation:

In order to explain this, is neccesary to draw both confomers, the cis and trans, but in the chair conformation, because in that way we can see much better the bonds and the reason of why the cis reacts faster than trans.

As you can see in picture attached, the more stable conformer is the one where the H and Br are in the axial position, and the tert butyl group in equatorial position. In these positions, the cis isomer can undergo an E2 reaction, and the ethoxide would have no problem to substract the hydrogen atom from the molecule to eliminate the Bromide. This is because the t-butyl group in equatorial position, is not exerting steric hindrance, therefore is faster.

In the case of the trans, the t-butyl group is in the axial position as well as the hydrogen and bromide, therefore, when the E2 reaction undergoes, the hydrogen is substracted by ethoxide, but it will be slow because the t.butyl group exerts steric hindrance in the axial positions, therefore, the hydrogen will be substracted slower than in the cis position. This is the main reason for the cis to be faster.

As for the second part of the question, which will be the answer of the whole question, see picture attached 2 for the whole sentence, and the match of the words is the following:

1. Axial

2. More

3. Blank (No word there)

4. less

5. Blank

6. Cis

7. Trans

8. Cis

Answer:

SO₂: 0.39atm

O₂: 3.645atm

Explanation:

Based on the reaction:

2 SO₂(g) + O₂(g) → 2 SO₃(g)

2 moles of sulfur dioxide react per mole of oxygen to produce 2 moles of sulfur trioxide.

When the reaction occurs an comes to equilbrium, the partial pressure of each gas is:

SO₂: 1.3atm - 2X

O₂: 4.1atm -X

SO₃: 2X

Where X is the reaction coordinate.

As pressure at equilibrium of SO₃ is 0.91 atm:

0.91atm = 2X

Thus: X = 0.455atm.

Replacing, pressures at equilibrium of the gases are:

SO₂: 1.3atm - 2×0.455atm = 0.39 atm

O₂: 4.1atm -0.455atm = 3.645 atm

Answer:

a negative ion, and an isotope.

Explanation:

The perfect atom consists of an equal balance in all 3. If the neutrons are not even with the protons, it is an isotope since it is like another version of the so called (but not actually) 'perfect' atom. If there is more electrons, the charge is negative, making it an ion.

Answer:B

Explanation:

Answer:

If you have 67.31 g of CH₄, you have 4.21 moles

Explanation:

To know the amount of moles if you have 67.31 g of CH₄, you must know the molar mass, that is, the mass of one mole of a substance, which can be an element or a compound.

On the periodic table, the molar mass of the elements, also called the atomic mass or atomic weight, can be found at the bottom of the element. In this case:

To calculate the molar mass of a compound, the molar mass of the elements of the compound must be added multiplied by the times they appear. So in this case the molar mass of CH₄ is:  

CH₄= 12 g/mole + 4* 1 g/mole= 16 g/mole

Now you can apply the following rule of three: if 16 g are contained in 1 mole of CH4, 67.31 g in how many moles are present?

[tex]moles=\frac{67.31 g*1 mole}{16 g}[/tex]

moles= 4.21

If you have 67.31 g of CH₄, you have 4.21 moles

Answer:

19656J

Explanation:

Step 1:

Data obtained from the question.

Mass (M) = 78g

Initial temperature (T1) = 20°C

Final temperature (T2) = 80°C

Change in temperature (ΔT) = T2 – T1 =

80°C – 20°C = 60°C

Specific heat capacity (C) = 4.2J/g°C

Heat (Q) =...?

Step 2:

Determination of the heat required for the reaction.

Q = MCΔT

Q = 78 x 4.2 x 60

Q = 19656J

Therefore, 19656J of heat is required.

Answer:

Solute

Explanation

A substance that gets dissolved to create a solution is best described as to as

Answer:

Depends on others to function

Explanation:

The question is missing information. Here is the complete question.

A gas at a pressure of 2.0 atm is in a closed container. Indicate the changes (if any) in its volume when the pressure undergoes the following changes at constant temperature and constant amount of gas. Match the words in the left with the column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer.

1. The pressure increases to 6.0 atm. The volume ________

2. The pressure drops to 0.40 atm. The volume _________

3. The pressure remains at 2.0 atm. The volume _________

Answer: 1. Decreases

2. Increases

3. Does not change

Explanation: According to the Ideal Gas Law, Pressure, Volume and Temperature of an ideal gas is related, as the following: PV = nRT.

In this case, since temperature (T) and amount of gas (n) are constant, the Boyle's Law can be used.

The law states that the volume of a given gas, under the conditios of temperature and amount of it are constant, is inversely proportional to the applied pressure: P₁.V₁ = P₂.V₂

Initial P (P₁) = 2

Initial V (V₁) = V

Final P (P₂) = 6

P₁.V₁ = P₂.V₂

2.V = 6.V₂

V₂ = 1/3V

When the pressure increases to 6 atm, volume decreases by 1/3.

P₁ = 2

V₁ = V

P₂ = 0.4

2.V = 0.4V₂

V₂ = 5V

When pressure drops to 0.4 atm, volume increases by 5.

Since there are no change in the pressure, the volume is the same from the beginning, so does not change.

Answer:

a

 The condensed structural formula for methane is

            [tex]CH_4[/tex]

b

 The condensed structural formula for ethane is

           [tex]CH_3 CH_3[/tex]

c

  The condensed structural formula for pentane is  

            [tex]CH_2(CH_2)_3CH_3[/tex]

d

   The diagram for the structural formula for cyclopropane is shown on the first uploaded image

Explanation:

Answer:

Explanation:

1 ) Ammonium bromide is a salt of ammonium hydroxide and hydrogen bromide . The former is a weak base and the later is a strong acid so the salt will make acidic solution in water. It happens due to salt hydrolysis.

2 ) Potassium cyanide is  salt of potassium hydroxide and hydrogen cyanide . The former is strong base and the later is weak acid so its salt will be basic in nature .

3 ) sodium chloride is a salt of sodium hydroxide and hydrogen chloride . The former is strong base and later is strong acid. So the salt is neutral .

4 ) Potassium iodide is a salt of potassium hydroxide and hydrogen iodide . The former is a strong base and the later is a strong acid . So the salt is neutral or a bit basic.