Pleaseee answer need help

Answer:

C

Explanation:

I just took the test

Answer:

B

Explanation:

Answer:

0.013 mole.

Explanation:

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

Time (t) = 94.6 mins

Current (I) = 224.8 mA.

Mole of electrons (e) =?

Next, we shall convert 94.6 mins to seconds. This is illustrated below:

1 min = 60 s

Therefore,

94.6 mins = 94.6 min × 60 s / 1 min

94.6 mins = 5676 s

Thus, 94.6 mins is equivalent to 5676 s.

Next, we shall convert 224.8 mA to ampere (A). This can be obtained as follow:

1 mA = 1×10¯³ A

Therefore,

224.8 mA = 224.8 mA × 1×10¯³ A / 1 mA

224.8 mA = 0.2248 A

Thus, 224.8 mA is equivalent to 0.2248 A.

Next, we shall determine the quantity of electricity flowing in circuit. This can be obtained as follow:

Time (t) = 5676 s

Current (I) = 0.2248 A

Quantity of electricity (Q) =?

Q = it

Q = 0.2248 × 5676

Q = 1275.96 C

Finally, we shall determine the mole of electron by converting the quantity of electricity (i.e 1275.96 C) to number of electrons. This can be obtained as follow:

96500 C = 1 e

Therefore,

1275.96 C = 1275.96 C × 1 e / 96500 C

96500 C = 0.013 e

Thus, the mole of electron trasfered in the process is 0.013 mole.

Answer:

This question is incomplete.

Explanation:

This question is incomplete because of the absence of given mass and volume, however, the steps below will help solve the completed question. The molarity (M) of a solution is the number of moles of solute per liter of solvent. The formula is illustrated below;

Molarity = number of moles (n) / volume (in liter or dm³)

To calculate the number of moles of NaC₂H₃O₂, we say

number of moles (n) =

given or measured mass of NaC₂H₃O₂ ÷ molar mass of NaC₂H₃O₂

The volume of the solvent must be in liter (same as dm³). Thus, to convert mL to liter, we divide by 1000

The unit for Molarity is M (Molar concentration), mol/L or mol/dm³

Answer:

1.B

2.A

3. B

Explanation:

1. A chemical bond is the physical phenomenon of chemical substances being held together by attraction of atoms to each other through sharing

2. so 2 is electrons of one atom are transferred permanently to another atom.meaning the answer is A

3. is When atoms combine by forming covalent bonds, the resulting collection of atoms is called a molecule. We can therefore say that a molecule is the simplest unit of a covalent compound.

A chemical bond is an attraction between two atoms.

A ionic bond is A bond formed when atoms transfer electrons.

The heat evolved with the [tex]\rm B_2H_6[/tex] has been 58.637 kJ.

From the balanced chemical equation, 1 mole of [tex]\rm B_2H_6[/tex] reacts with 2 moles of Chlorine to give 3 moles of boron chloride and 6 moles of HCl,

The chlorine has been required in double the quantity of boron hexahydride.

The moles of Chlorine has been the limiting reactant.

The chlorine that has been responsible for the reaction with [tex]\rm B_2H_6[/tex] will be:

6 Chlorine = 1 [tex]\rm B_2H_6[/tex]

5.65 L Chlorine = [tex]\rm \dfrac{5.65}{6}[/tex]

5.65 L Chlorine = 0.942 L [tex]\rm B_2H_6[/tex].

The moles of [tex]\rm B_2H_6[/tex] can be calculated as:

1 Mole = 22.4 L

Moles of [tex]\rm B_2H_6[/tex] in 0.942 L = 0.042 mol.

The heat evolved for 1 mole [tex]\rm B_2H_6[/tex] has been -1396 kJ.

The heat evolved for 0.042 mol [tex]\rm B_2H_6[/tex] = 0.042 × -1396 kJ.

The heat evolved = 58.637 kJ.

The heat evolved with the [tex]\rm B_2H_6[/tex] has been 58.637 kJ.

For more information about the heat evolved, refer to the link:

https://brainly.com/question/24245395

Answer:

Physical change because it can go back to its original form.

Explanation:

Answer:

-1.94  * 10^-18 J

Since the electron moved from a higher to a lower energy level (n = 3 → n = 1) it is an emission.

Explanation:

From Rydberg equation;

E = -RH(1/n^2final - 1/n^2initial)

For a transition from  n = 3 → n = 1

RH = 2.18 * 10^-18 J

E = -(2.18 * 10^-18) (1/1^2 - (1/3^2)

E = -(2.18 * 10^-18) (1-1/9)

E= -(2.18 * 10^-18) (8/9)

E = -1.94  * 10^-18 J

Answer:

Dissolves in water: Acetone, 1-propanol, Methanol

Do not dissolve in water: Hexane, Decane

Explanation:

From the principle that like dissolves like,polar substances will dissolve in polar solutions, while non-polar substances will dissolve in non-polar substances.

Water is a polar solution, therefore, polar substances will dissolve in it.From the given options:

Acetone is a polar molecule, therefore, it will dissolve in water.

1-propanol is a polar molecule, therefore, it will dissolve in water.

Hexane is a non-polar molecule, therefore, it will not dissolve in water.

Methanol is a polar molecule, therefore, it will dissolve in water.

Decane is a non-polar molecule, therefore, it will not dissolve in water

Answer:

1st one is...

Explanation:

The 1st one is change in size or shape. 2nd one is formation of precipitate. 3rd one is physical change. 4th one is formation of gas.

Answer:

4 m

Explanation:

Answer:

Is it multiple choice or what I need to know the details

Explanation:

Answer:

Average atomic mass of chlorine is 35.48 amu.

Explanation:

Given data:

Percent abundance of Cl-35 = 76%

Percent abundance of Cl-37 = 24%

Average atomic mass = ?

Solution:

Average atomic mass  = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass)  / 100

Average atomic mass  = (76×35)+(24×37) /100

Average atomic mass =  2660 + 888 / 100

Average atomic mass  = 3548/ 100

Average atomic mass = 35.48 amu

Average atomic mass of chlorine is 35.48 amu.

Answer:

wersawess. uioiiiuioii

Explanation:

shhshsbshsjbsnsbxbxjzn, jznshdkbdjdjsnsj

Answer:

ok

asap what is the meaning of it?

The value of x​ : 2

Semi-normal Hydrochloric acid solution = 0.5 N = 0.5 M

for titration :

M₁V₁n₁=M₂V₂n₂(1=HCl,2=Na₂CO₃)

[tex]\tt 0.5\times 20\times 1=M_2\times V_2\times 2\\\\M_2V_2=5~mlmol=5.10^{-3}mol[/tex]

[tex]\tt MW=\dfrac{mass}{mol}=\dfrac{0.715}{5.10^{-3}}=143~g/mol[/tex]

MW Na₂CO₃.xH₂O=143

MW Na₂CO₃.xH₂O = MW Na₂CO₃+ MW xH₂O = 143

MW Na₂CO₃ = 106 g/mol

MW xH₂O = 18x

Equation :

[tex]\tt 106+18x=143\\\\18x=37\\\\x=\dfrac{37}{18}=2.056\approx 2[/tex]

Answer:

Magnesium oxide is an ionic compound that can be used as a building material. MO2 is actually a raw material that used in producing cement for building houses, buildings, and other constructions.

Explanation:

Answer:

Climate change

Explanation:

Climate change is primarily a problem of too much carbon dioxide (CO2) in the atmosphere. This carbon overload is caused mainly when we burn fossil fuels like coal, oil and gas or cut down and burn forests

Answer:

Answer : The volume of water and alcohol present in 675 mL of this solution is 405 mL and 270 mL respectively.

Explanation: As we are given that 40.0 % (v/v) alcohol solution. That means, 40.0 mL of alcohol present in 100 mL of solution.

Now we have to calculable the volume of alcohol in 675 mL solution.

As 100 mL of solution contains 40.0 mL of alcohol

So, 675 mL of solution contains alcohol

Thus, the volume of alcohol = 270 mL

Now we have to calculate the volume of water.

The volume of water = Volume of the solution - Volume of alcohol

Volume of water = 675 mL - 270 mL

The volume of water = 405 mL

Thus, the volume of water = 405 mL

Hence, the volume of water and alcohol present in 675 mL of this solution is 405 mL and 270 mL respectively.

The 720mL of an 80-proof brandy which is 40.0% (v/v) ethyl alcohol, contains 288 mL of ethyl alcohol.

The Percent solutions can be expressed in the form of volume/volume percentage, weight/volume percentage, or, weight/weight percentage. The concentration of the solution in percentage is calculated as the fraction of the weight or volume of the solute related to the total weight or volume of the solution.

The solution where concentration requires to be represented in volume percent (v/v%) when the solute is a liquid phase. It is also applicable to the numerator and the denominator in volume units and is called volume/volume percent.

Volume percentage = (Volume of solute/volume of solution) x 100

The given brandy has ethyl alcohol the v/v % is 40 %.

It means the 40 ml of ethyl alcohol is present in the 100ml of brandy

Given the volume of brandy = 720 ml

Volume of ethyl alcohol in 720 ml of brandy = (40/100)×720 = 288 ml

Therefore, 288 ml of ethyl alcohol is present in 720 ml of brandy which is 40.0% (v/v) ethyl alcohol.

Learn more about volume/volume percentage, here:

https://brainly.com/question/13558694

#SPJ2

Your question is incomplete, but most probably complete question was,

An 80 proof brandy is 40.0% (v/v) ethyl alcohol. The "proof" is twice the percent concentration of alcohol in the beverage. How many milliliters of alcohol are present in 720 mL of brandy?

Answer:

6.711 × 10²⁴ molecules Mg(OH)₂

General Formulas and Concepts:

Chemistry - Atomic Structure

Explanation:

Step 1: Define

650.0 g Mg(OH)₂

Step 2: Define conversions

Avogadro's Number

Molar Mass of Mg - 24.31 g/mol

Molar Mass of O - 16.00 g/mol

Molar Mass of H - 1.01 g/mol

Molar Mass of Mg(OH)₂ - 24.31 + 2(16.00) + 2(1.01) = 58.33 g/mol

Step 3: Convert

[tex]650.0 \ g \ Mg(OH)_2(\frac{1 \ mol \ Mg(OH)_2}{58.33 \ g \ Mg(OH)_2} )(\frac{6.022 \cdot 10^{23} \ molecules \ Mg(OH)_2}{1 \ mol \ Mg(OH)_2} )[/tex]

= 6.71061 × 10²⁴ molecules Mg(OH)₂

Step 4: Check

We are given 4 sig figs. Follow sig fig rules.

6.71061 × 10²⁴ molecules Mg(OH)₂ ≈ 6.711 × 10²⁴ molecules Mg(OH)₂

Answer:

0.44L

Explanation:

Given parameters:

  Initial volume  = 0.75L

  Initial temperature  = 25°C  = 273 + 25 = 298K

  Final temperature  = -100°C  = 273 + (-100) = 173K

Unknown:

New volume of the balloon = ?

Solution:

According to Charles's law;

   "the volume of a fixed mass of a gas varies directly as its absolute temperature if the pressure is constant".

Mathematically;

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

  V and T are temperature values

  1 and 2 are the initial and final states

Insert the parameters and solve;

   [tex]\frac{0.75}{298}[/tex]   = [tex]\frac{V_{2} }{173}[/tex]  

    298V₂   = 129.75

           V₂  = 0.44L

The 12 stands for the number of electrons that fill the f orbital

In an atom there are levels of energy in the shell and sub shell  

This energy level is expressed in the form of electron configurations.  

Writing electron configurations starts from the lowest to the highest sub-shell energy level. There are 4 sub-shells in the shell of an atom, namely s, p, d and f. The maximum number of electrons for each sub shell is  

• s: 2 electrons  

• p: 6 electrons  

• d: 10 electrons and  

• f: 14 electrons  

4f¹² :

4 : number of shell

12 : the number of electrons that fill the f orbital

Answer:hi

Explanation:

Answer:

Element Symbol # of Atoms

Sodium   Na   2

Cobalt   Co   3

Hydrogen  H  20

Oxygen   O   10

Explanation:

Answer:

Explanation:

In carbon monoxide ,

2.5 g of carbon reacts with 3.33 g of oxygen

In unknown gas X ,

.75 g of carbon reacts with 2 .00 g of oxygen

2.5 g of carbon will react with 6.66 g of oxygen in X gas .

Ratio of oxygen in two compounds , reacting with same mass of carbon

= 3.33 : 6.66

= 1 : 2 , a simple ratio

It follows law of multiple proportions .

First gas is CO or carbon monoxide

X gas is CO₂ or carbon dioxide .

In this gas , ratio of oxygen reacting with same amount of carbon is doubled .

Answer:

d. the relative proportions of the elements in the compound.

Explanation:

The chemical formula of a compound indicates the relative proportions of the element in the compound.