Which of these half-reactions represents reduction?
I. Fe2+ → Fe3+
II. Cr2O72- → Cr3+
III. MnO4- → Mn2+

Answer:

Mg + 2H₂O —> Mg(OH)₂ + H₂

Explanation:

Mg + H₂O —> Mg(OH)₂ + H₂

The above equation can be balance as illustrated below:

Mg + H₂O —> Mg(OH)₂ + H₂

There are 2 atoms of H on the left side and a total of 4 atoms on the right side. It can be balance by writing 2 before H₂O as shown below:

Mg + 2H₂O —> Mg(OH)₂ + H₂

Now, the equation is balanced

****Check***

Element >>>>> Reactant >>>> Product

Mg >>>>>>>>>> 1 >>>>>>>>>>> 1

H >>>>>>>>>>> 4 >>>>>>>>>>> 4

O >>>>>>>>>>> 2 >>>>>>>>>>> 2

The balanced equation of Mg + H2O = Mg(OH)2 + H2​ is given as

Mg + 2H₂O —> Mg(OH)₂ + H₂

Generally, the equation for the Chemical equation  is mathematically given as

Mg + H₂O —> Mg(OH)₂ + H₂

Therefore, We se that  we have on the LHS

Mg=1

H=2

O=1

and on The RHS

Mg=1

H=4

O=2

Therefore to balance, we add 2 to H and 1 to O giving

Mg + 2H₂O —> Mg(OH)₂ + H₂

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Solution :

The partition coefficient

[tex]$k_d= \frac{\text{(mass of caffeine in }CH_2Cl_2 / \text{volume of }CH_2Cl_2)}{\text{(mass of caffeine in water/ volume of water)}}$[/tex]

   = 9.0

A). 1 x 200 mL extraction

Let m be the mass of caffeine in water

Mass of caffeine in [tex]$CH_2Cl_2$[/tex] = 100 - m

∴ [tex]$\frac{(100-m)/200}{m/200}=9$[/tex]

  [tex]$\frac{100-m}{m}=9$[/tex]

  [tex]$10 \ m = 100$[/tex]

[tex]$m=\frac{100}{10}$[/tex]

     = 10

Therefore, the mass remaining in the coffee is m = 10 mg

B). 2 x 100 mL extraction

First extraction :

Let [tex]$m_1$[/tex] be the mass of the caffeine in water.

Mass of caffeine in [tex]$CH_2Cl_2$[/tex] = 100 - m

∴ [tex]$\frac{(100-m_1)/100}{m_1/200}=9$[/tex]

  [tex]$\frac{100-m_1}{m_1}=9$[/tex]

  [tex]$5.5 \ m_1 = 100$[/tex]

[tex]$m_1=\frac{100}{5.5}$[/tex]

     = 18.18

Mass remaining in the coffee after the 1st extraction [tex]$m_1$[/tex] = 18.18 mg

Second extraction:

Let [tex]$m_2$[/tex] be the mass of the caffeine in water.

Mass of caffeine in [tex]$CH_2Cl_2$[/tex] = 18.18 - [tex]$m_2$[/tex]

∴ [tex]$\frac{(18.18-m_2)/100}{m_2/200}=9$[/tex]

  [tex]$\frac{18.18-m_2}{m_2}=9$[/tex]

  [tex]$5.5 \ m_2 = 18.18$[/tex]

[tex]$m_1=\frac{18.18}{5.5}$[/tex]

     = 3.3

Mass remaining in the coffee after the 1st extraction [tex]$m_2$[/tex] = 3.3 mg

Answer:

Explanation:

It orbits

n = 0.0395 mol Xe

Explanation:

Use the ideal gas law:

PV = nRT

n = PV/RT

= (1.15 atm)(0.786 L)/(0.08205 L-atm/mol-K)(279K)

= 0.0395 mol Xe

Answer: 30.978

Explanation:

From the equation 2 moles of Fe will result in 3 moles copper

so .325 moles Fe will result in .4875 moles Cu

Cu weights 63.546 gm per mole

.4875 moles * 63.546 gm / mole = 30.978 gm of Cu

Answer:طيزي

Explanation:

1- Topsoil

2- Bedrock

3- Humus

4- Loam

5- Acyl, Clay, or Lacy

Well that was fun :)

Answer:

Explanation:

1. TOPSOIL

2. BEDROCK

Answer:

1. Ions are either negatively or positively charged species in which the number of electrons and protons are not equal.

2. The chemical bond that arises due to the sharing of electrons is termed a covalent bond.

3. The positively charged ions are called cations, which comprise more protons than electrons.

4. An example of a polyatomic anion is the hydroxide anion.

5. The system of assigning an unambiguous name to a compound is called nomenclature.

Answer:

Suppose you added some solid NaCl to a saturated solution of NaCl at 20℃ and warmed the mixture to 40℃. What would happen to the added NaCl?

Explanation:

can you help with this one

Answer:

Production of liquid oxygen from air Oxygen is generated by liquefaction of atmospheric air in the air separation unit (ASU). Cryogenic technique is the most commonly used for producing liquid oxygen for industrial and medical applications .

Explanation:

An air separation unit (ASU) uses continuous cryogenic distillation to continuously liquefy ambient air and separate the oxygen gas.

Oxygen is the second largest abundant element in the atmosphere comprising 20.8% by volume. Despite being mostly used as a gas, oxygen is frequently stored as a liquid. Compared to high-pressure gaseous storage with a similar capacity, liquid storage is less expensive and bulkier.

A cryogenic storage tank, one or more vaporizers, and a pressure control system make up a typical storage system. The cryogenic tank is built similarly to a vacuum bottle.

The primary air compressor is where the ASU manufacturing process starts, and the product storage tanks' output is where it concludes. Moisture, carbon dioxide, and hydrocarbons are taken out of the air after it has been compressed and put through a purification system.

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Answer:

d

Explanation:did test

Answer:

Water molecule has hydrogen bonding and surface tension

Explanation:

Intermolecular behavior of water is different from that of the intermolecular force of oil because water molecule is polar in nature while oil molecule is non polar. Dur to polar nature, water molecule has high surface tension which keep its atoms intact. Also the water molecule being polar also exhibit hydrogen bonding between hydrogen (+ive) and oxygen atom (-ive)

Answer:

I)Acetylene

II)2-Methyl-1-butanol

Explanation:

I)appears as a colorless gas with a faint garlic-like odor. Easily ignited and burns with a sooty flame. Gas is lighter than air.

Answer:

See explanation

Explanation:

Given the reaction;

3N2(g) + H2(g) = 2N3H(g).

We know that when a constraint is imposed on a reaction system in equilibrium, the equilibrium position will shift in such a way as to annul the constraint.

In this case, when the pressure is increased eightfold, the equilibrium position will shift towards the direction where there is the least total volumes.

In this particular reaction, the forward reaction has the least total volumes and is favoured by an eightfold increase in pressure.

Hence, when the pressure is increased eightfold, more N3H(g) is obtained.

Answer:

6.59 g/cm³

Explanation:

Step 1: Given data

Step 2: Calculate the volume of the cube

We will use the following expression.

V = s³ = (2.54 cm)³ = 16.4 cm³

Step 3: Calculate the density of the solid

Density is an intrinsic property, equal to the quotient between the mass and the volume.

ρ = m/V

ρ = 108 g / 16.4 cm³ = 6.59 g/cm³

Answer:

0.871 mL

Explanation:

Step 1: Write the balanced neutralization reaction

KOH + HF ⇒ KF + H₂O

Step 2: Calculate the reacting moles of HF

9.55 mL of 0.114 M HF react.

9.55 × 10⁻³ L × 0.114 mol/L = 1.09 × 10⁻³ mol

Step 3: Calculate the moles of KOH needed to react with 1.09 × 10⁻³ moles of HF

The molar ratio of KOH to HF is 1:1. The moles of KOH needed are 1/1 × 1.09 × 10⁻³ mol = 1.09 × 10⁻³ mol.

Step 4: Calculate the volume of KOH solution that contains 1.09 × 10⁻³ moles of KOH

An unknown volume of 1.252 M KOH solution contains 1.09 × 10⁻³ moles of KOH.

1.09 × 10⁻³ mol × 1 L/1.252 mol = 8.71 × 10⁻⁴ L = 0.871 mL

Answer:

589 torr or mmHg.

Explanation:

We know that 1 atmospheric pressure is equal to 760 torr or 760 mmHg so calculate 0.775 atm pressure in term of mmHg and torr. We perform the following steps which is

1 atm -------- 760 torr or mmHg

0.775 atm ------- X

By cross multiplication we get

X = 760 x 0.775

X = 589 torr or mmHg

So we can conclude that if 0.775 atm is equals to 589 torr.

Answer:

Number of moles  of sodium dissolved =  6.0 *10^23

Explanation:

The image for the question is attached

Solution

a) Total 181 ions of Na are dissolved

b)

The number of moles of sodium dissolved = 181/6.023 *10^23

Number of moles  of sodium dissolved = 5.987 * 10^23

Number of moles  of sodium dissolved =  6.0 *10^23

above because its above

1. You didn't post the question to Number 1.

2.

10% means There's 10g in 100ml of this solution.

This is the weight/volume(w/v) expression of concentration.

So

We have Mass =10g

volume =100ml

Molarity = Moles of solute/volume of solution(in LITRES)

Moles=Mass/Molar mass

Molar mass of NaOH=40g/mol

Mole=10/40

=0.25mole

Volume =100ml =0.1Litres

MOLARITY=0.25/0.1 =

=2.5M

OPTION B.

3. NOTE: THE MOLARITY AND NORMALITY OF NAOH AND HCL ARE THE SAME(This doesn't happen for all compounds tho)

So We can take 2.5N(Normality) of NaOH to be 2.5M(Molarity) NaOH

I think you forgot to write the Normality of the second one. I'll take it to be 1N. Maybe you can then Input supposed value when you're solving on your own

So

1N HCl is same as 1M HCL

We were given their respective volumes

2.5M NaOH can also be written as 2.5mole/volume(in Liters)

The volume of NaOH =10ml or 0.01L

Moles = 2.5mole/L x 0.01L

You notice that Liters on top and bottom cancels out... leaving the moles

So

Mole=0.01x2.5 = 0.025moles of NaOH

we're gonna do the same for 1N HCl in 20ml(0.02L)

So

Mole = 1 x 0.02 =0.02moles

Total Mole = 0.02 + 0.025 =0.045moles

The Final Volume is 100ml as stated in the question. It was diluted to 100ml or 0.1L

So

Final Concentration In Molarity

= Total Moles/Volume in L

=0.045/0.1

=0.45M.

Answer:

follow me and pm and I answer your question

Answer:

70.6 %

Explanation:

First step, we define the reaction:

2P + 3Br₂  →  2PBr₃

We determine the moles of reactant:

35 g . 1mol / 159.8 g = 0.219 moles

We assume, the P is in excess, so the bromine is the limiting reagent.

3 moles of Br₂ can produce 2 moles of phophorous tribromide

Then, 0.219 moles may produce (0.219 . 2) /3 = 0.146 moles of PBr₃

We convert moles to mass:

0.146 mol .  270.67 g /mol = 39.5 g

That's the 100 % yield reaction, also called theoretical yield. The way to determine the % yield is:

(Yield produced / Thoeretical yield) . 100

(27.9 / 39.5) . 100 = 70.6 %

Answer: The pH of the solution is 2.74.

Explanation:

To calculate the pH of the acidic buffer, the equation for Henderson-Hasselbalch is used:

[tex]pH=pK_a+\log (\frac{\text{[conjugate base]}}{\text{[acid]}})[/tex]         .......(1)

The power of the acid dissociation constant is the negative logarithm of the acid dissociation constant. The equation for it is:

[tex]pK_a=-log K_a[/tex]        ......(2)

The chemical equation for the reaction of acetic acid and NaOH follows:

[tex]CH_3COOH+NaOH\rightleftharpoons CH_3COONa+H-2O[/tex]

Given values:

[tex]K_a=1.8\times 10^{-5}[/tex]

Putting values in equation 2:

[tex]pK_a=-log (1.8\times 10^{-5})\\\\pK_a=4.74[/tex]

We are given:

[tex]CH_3COOH[/tex] = 0.1 M

[tex]CH_3COONa[/tex] = 0.001 M

Plugging values in equation 1:

[tex]pH=4.74+\log (\frac{0.001}{0.1})\\\\pH=4.74-2\\\\pH=2.74[/tex]

Hence, the pH of the solution is 2.74.

Answer:

The balanced equation will be your greatest asset in Solving this.

The Balanced Equation is

3Cl2 + 8NH3---> N2 + 6NH4Cl

So

From this reaction...

3 moles of NH3 is required to produce 6 moles of NH4Cl

Now the question asked.... How Many Moles of NH3 will be needed to produce 12moles of NH4Cl?...

The answer is simply 6moles of NH3.

Why?

Since 3moles of NH3 produce 6 moles of NH4Cl

It makes sense that

6moles of NH3 will produce 12moles of NH4Cl.

Its a simple Ratio.

Hope this helps...

I'm Open to questions if you have any.

Have a great Day!

Answer:

2Na and 2HCl

Explanation:

The equation for the above chemical reaction is as follows:

2Na + 2HCI → 2NaCl + H2

In a reaction, the reactants are said to be those that combine together to form products. In this case, sodium (Na) and hydrochloric acid (HCl) are the reactants of this reaction

Answer:

26 Hydrogen atoms

Explanation:

H2O

Each hydrogen atom: 2+16 = 18g

Hence,

1 atom -> 18g

x atoms -> 709g

709/18 = 39 atoms

Therefore, 39 atoms give 709g

Hence, 26 Hydrogen atoms are used

Feel free to mark it as brainliest :D

Answer:

a)   1.12 MeV / nucleon

b)   5.62 MeV / nucleon

c)  8.80 MeV / nucleon

d) 8.56 MeV / nucleon

we can conclude that the binding energy has a maximum value for nuclei with a mass around 60

Explanation:

Binding energy = ( Δm * 931.5 ) MeV

Binding energy per nucleon = Binding energy in / Number of nucleon

a) ²H = 1 neutron , 1 proton = 2 nucleons

Given that the theoretical mass = 2.0141 u

Actual mass = 1.0078 u + 1.0087 u = 2.0165 u

Δm  = 2.0165 u - 2.0141 u = 2.4 * 10^-3 u

∴ Binding energy per nucleon = ( 2.4 * 10^-3  * 931.5 ) MeV / 2 nucleons

                                                  = 1.12 MeV / nucleon

b) ⁷Li = 3 protons , 4 neutrons = 7 nucleons

theoretical mass = 7.0160 u

Actual mass = ( 3 * 1.0078 ) + ( 4 * 1.0087 )  = 7.0582 u  

Δm  = ( 7.0582 u  - 7.0160 u  ) = 0.0422 u

∴ Binding energy per nucleon = ( 0.0422 * 931.5 ) / 7

                                                  = 5.62 MeV / nucleon

C) ⁶²Ni = 28 protons , 34 neutrons = 62 nucleons

Theoretical mass = 61.9283 u

Actual mass = ( 28 * 1.0078 ) u + ( 34 * 1.0087 ) u

                    = 62.5142 u

Δm = 0.5859 u  

∴ Binding energy per nucleon = ( 0.5859 * 931.5 ) / 62

                                                  = 8.80 MeV / nucleon

D) ¹¹⁰Cd = 48 protons , 62 neutrons = 110 nucleons

Theoretical mass = 109.9030 u

Actual mass = ( 48 * 1.0078 ) + ( 62 * 1.0087 )

                    = 110.9138 u

Δm  = ( 110.9138 - 109.9030 ) = 1.0108 u

∴ Binding energy per nucleon = ( 1.0108 * 931.5 ) / 110

                                                  = 8.56 MeV / nucleon

hence we can conclude that the binding energy has a maximum value for nuclei with a mass around 60

Answer:

1. Washing dishes and cooking

2. Water is used as a solvent in the manufacture of beverages and it is also largely used in agriculture.

3. Water conservation is the action of using water wisely and not wasting it.

4. i) Wash dishes in a tub of water instead of under a running tap.

ii) Use a pail of water to wash the car instead of spraying water from a hose.

iii) Make sure that there are no leaking or broken taps and pipes.

Answer:

Washing dishes and cooking

2. Water is used as a solvent in the manufacture of beverages and it is also largely used in agriculture.

3. Water conservation is the action of using water wisely and not wasting it.

4. i) Wash dishes in a tub of water instead of under a running tap.

ii) Use a pail of water to wash the car instead of spraying water from a hose.

iii) Make sure that there are no leaking or broken taps and pipes.

Explanation: