Calculate the pH and pOH of aqueous solutions with the following concentrations.[OH﹘] = 1.0 x 10-7M

Group 17 is located on the right side of the periodic table. The atomic radius increases from right to left. It means that group 17 elements have a small atomic radius. Also, they have only one electron in the valence shell, their ionization energy is low, and it is easy to lose that electron. This fact explains its high reactivity.

Answer: Nonmetals have a small atomic radius and can lose electrons easily.

Answer

Carbon (C)

Procedure

The initial oxidation states of our balanced reaction are

Reduction is the gain of electrons or a reduction in the oxidation state of an atom, ion, or certain atoms in a molecule.

Oxidation is the loss of electrons or an increase in the oxidation state of an atom, ion, or certain atoms in a molecule.

Therefore we conclude that carbon is being oxidized.

The final temperature of a 496−g sample of water, initially at 17.0°C, after 74.2 kJ have been added to it is 52.61°C.

Given,

Mass of sample water, m = 496g

Initial temperature of the water, t1 = 17°C

Heat added to the water, Q = 74.2 kj = 74200 kj

The quantity of the heat which is added in water to cause a change in the state of the sample water can be given as

Q = mc∆t

where

c is given as specific heat capacity of water = 4200J/kg°C

∆t = change in temperature of the water

The change in temperature of the water after adding heat is given as

∆t = Q/ mc

By substituting all the values, we get

= 74200/ 0.496 × 4200

= 35.61°C

Thus, from the calculated data we get the value of final temperature

change in temperature = Final temperature - initial temperature

Final temperature = 35.61 + 17 = 52.61°C

Thus, we concluded that the final temperature of a 496−g sample of water, initially at 17.0°C, after 74.2 kJ have been added to it is 52.61°C.

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Answer: 7 atoms

Explanation:

Answer:

5 atoms

Explanation:

Pb= 1 atom

N = 1 atom

O = 3 atoms

Thus, total no. of atoms are 5

The pH of 0.00339 M solution of NaF when Ka for HF is 6.8 x 10^-4 is 7.34

In this case, it is the base, F-.  A reaction table for base ionization, which is the reaction of a base with water:

F- + H2O <===> HF + OH-

Kb  =  [OH-][HF] / [F-]

Ka = 6.8 x 10-4

Kb =   1.47 x 10-11

 1.47 x 10-11 = [x] [x] / 0.00339-x  =  [x] [x] / 0.00339 ( x << than 0.00339 M due to the small Kb)

x  = 2.23 x 10-7

pOH =  6.65

pH =  14-6.65 = 7.34

pH = 7.34

The pH is 7.34

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The number of protons, neutrons, and electrons in isolated ions having the following nuclear symbols:

a) ¹⁹F⁻ has 9 protons  , 9 neutrons ,  10 electrons

b) ²⁴Mg²⁺ has 12 protons , 12 neutrons , 10 electrons

c) ⁵⁶Fe³⁺ has 26 protons , 26 neutrons , 23 electrons

Atomic number represent the no. of protons. number of protons is equal to number of electrons in neutral atom. neutrons is the difference between mass number and atomic number.

a) Atomic number of fluorine is 9. for neutral F atom  has 9 protons , 9 neutrons , 9 electrons. In ¹⁹F⁻ , -1 represents one extra electron.

¹⁹F⁻  has 9 protons  , 9 neutrons ,  10 electrons

b) Atomic number of Magnesium is 12. In ²⁴Mg²⁺ , 2+ represents 2 electrons are removed.

²⁴Mg²⁺ has 12 protons , 12 neutrons , 10 electrons

c) Atomic number of iron is 26.

⁵⁶Fe³⁺  has 26 protons , 26 neutrons , 23 electrons

Thus, The number of protons, neutrons, and electrons in isolated ions having the following nuclear symbols:

a) ¹⁹F⁻  has 9 protons  , 9 neutrons ,  10 electrons

b) ²⁴Mg²⁺ has 12 protons , 12 neutrons , 10 electrons

c) ⁵⁶Fe³⁺ has 26 protons , 26 neutrons , 23 electrons

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In this question, we have the following reaction:

2 SO2 + O2 -> 2 SO3, this reaction is already balanced

Considering molar ratio, we have:

2 SO2 = 1 O2

2 SO2 = 2 SO3

1 O2 = 2 SO3

Now, we need to find the limiting reactant, we will do it by checking the number of moles of both SO2 and O2 and compare it with the molar ratio

Let's start with SO2, molar ratio = 64.066g/mol

64.066g = 1 mol

35.0g = x moles

x = 0.546 moles of SO2 in 35 grams

According to the molar ratio, if we have 0.546 moles of SO2, we need half of it of O2, therefore:

0.546/2 = 0.273 moles of O2 is required

We need to check the number of moles of O2 to analyze if we have less or more moles than we actually need, O2 molar mass = 32g/mol

32g = 1 mol

35g = x moles

x = 1.094 moles of O2

If we have 1.094 moles and we need only 0.273 moles, this means that O2 is in excess and SO2 is the limiting reactant

Using the limiting reactant we can find the mass produced of SO3, according to the molar ratio, we will have the same number of moles from both SO2 and SO3, 0.546 moles

Now to find the mass, we use the number of moles, 0.546 and also the molar mass of SO3, 80.06g/mol

80.06g = 1 mol

x grams = 0.546 moles

x = 43.71 grams of SO3

Limiting reactant = SO2

Excess reactant = O2

SO3 formed = 43.71 grams

a) The molarity of Cl⁻ in 0.200 M of NaCl is 0.200 M.

a) The molarity of Cl⁻ in 0.190 M of SrCl₂ is 0.380 M.

c) The molarity of Cl⁻ in 0.110 M of AlCl₃ is 0.330 M.

a) 0.200 M of NaCl

The chemical reaction,

NaCl(aq) → Na⁺(aq) + Cl¯(aq)

From the above-balanced equation,

1 mole of Cl was created from 1 mole of NaCl

Therefore,

0.200 M NaCl will produce 0.200 M of Cl⁻

b) 0.190 M of SrCl₂

The chemical reaction:

SrCl₂(aq) → Sr²⁺ (aq) + 2Cl¯ (aq)

From the above-balanced equation,

2 moles of Cl were created from 1 mole of SrCl2.

Hence,

0.190 M of SrCl₂ will produce = 0.190 × 2 = 0.380 M of Cl⁻

c) 0.110 M of AlCl₃

The chemical reaction:

AlCl₃(aq) → Al³⁺ (aq) + 3Cl¯ (aq)

From the above-balanced equation,

3 moles of Cl were created from 1 mole of AlCl₃

Hence,

The molarity of Cl⁻ in 0.110 M of AlCl₃ is:

= 0.110 × 3 = 0.330 M

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Electron configuration is defined as the description of where each electron is located, in terms of levels and sublevels around the nucleus. In this question, we have the following electron configuration:

1s2 2s2 2p6 3s2 3p6

This electron configuration has 8 electrons in its valence shell (the last number represents the shell number, in this case is 3) and according to the octet rule, this is a stabilized element, therefore it must be a Noble Gas

The period will be 3, since this is the valence shell

The group will be Noble gas, or group 18

Noble gas, usually, will not bond to other elements, since they are stabilized according to the octet rule

This is an ideal gas problem, so let's see the relationships of volume with pressure and temperature:

- The relationship between volume and pressure is inversely proportional.

- The relationship between volume and temperature is directly proportional.

When the gas's volume decreases, the temperature would decrease too but the pressure would increases, so the answer would be B. Its pressure increased.

Step 1 - Balancing the combustion equation

The combustion of an alkane always gives, as products, H2O and CO2. Remembering that combustion always involves a reaction with O2, we can write the chemical equation for the combustion of C4H10 as:

Step 2 - Discover how many grams of carbon dioxide can be produced

Looking at the equation above, we can see that 1 mole of C4H10 produces 4 moles of CO2. This is a fixed proportion. We can convert this proportion in moles to a proportion in mass by multiplying each number of moles by the respective molar mass (C4H10 58g/mol; CO2 44g/mol)of the substances:

We discovered thus that each 58 g of C4H10 produce 176g of CO2. Since this is a fixed proportion in mass, we can use it to discover how many grams of CO2 would be formed by the combustion of 20g of butane (C4H10):

The combustion of 20 g of C4H10 would produce thus 60.7 g of CO2.

The number of moles of excess reagent left after the reaction is complete would be  sodium phosphate  and The mass of excess reagent that will remain unreacted is copper (II) nitrate.

The molar amounts of reactants and products that will result from a balanced chemical equation are shown. Rarely are reactants combined in the exact amount required in the actual world. Before the others, one reactant will be entirely depleted. The limiting reactant is the one that is consumed first in a reaction. The residual amount is deemed "in excess" once the other reactants have been partially consumed.

Calculate the volume of the product each reactant produced to identify the limiting reactant. The limiting reactant is the one that yields the smallest amount of product.

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We can find molarity using the following equation:

In this problem, our solute is CaCO3, and we have 15.7 g of it. To express this amount in moles, what we do is to divide by the molar weight of CaCO3. (Always that you want to pass from grams to moles you do this, just to divide the amount that you have by the molar weight of the substance).

This is:

Now, we have 275mL of solution and this is 0.275L of solution. (To pass from mL to L we just divide by 1000).

Finally, replacing in the formula to find molarity, we have:

The answer is 0.57M.

Answer

A - Iodine is being oxidized

B - Cl2 is being reduced

Explanation

Answer

The molar mass of N₂O₃ = 76.0104 g/mol

Step-by-step explanation:

Using the atomic masses of elements from the periodic table; (N = 14.0067, O = 15.999).

Therefore, the molar mass of dinitrogen trioxide is calculated below.

N₂O₃ = 2(N) + 3(O)

N₂O₃ = 2(14.0067) + 3(15.999)

N₂O₃ = 28.0134 + 47.997

N₂O₃ =76.0104 g/mol

The molar mass of N₂O₃ = 76.0104 g/mol

The viscosity of the liquid will be increasing.

The bond that holds the particles of liquid together is weak compared to solid.

The application of heat to a substance gradually causes a decrease in its viscosity because the molecules of the liquid substance get excited when the liquid is heated up.

When the temperature of the liquid is gradually decreased, the energy that causes the molecules to move will no longer be enough to overcome the forces that bind the molecules together causing the liquid to become thicker and increasing the viscosity of the liquid.

Therefore we can conclude that when the temperature of a liquid is gradually decreased, the viscosity of the liquid will be increasing.

Answer: Beryllium Chloride

The number of moles of [tex]Cl_2[/tex] required to produce 250 grams of [tex]PCl_5[/tex] would be 3 moles.

Phosphorus and chlorine react to form phosphorus pentachloride according to the following balanced equation:

[tex]2P + 5Cl_2 -- > 2PCl_5[/tex]

From the equation of the reaction, the mole ratio of chlorine and phosphorus pentachloride is 5:2. Thus, 5 moles of chlorine will produce 2 moles of phosphorus pentachloride.

Recall that: mole = mass/molar mass

The molar mass of [tex]PCl_5[/tex] is 208.24 g/mol

Thus, 250 g of [tex]PCl_5[/tex] would be equivalent to:

mole = 250/208.24

         = 1.20 mol

2 mol [tex]PCl_5[/tex] = 5 moles [tex]Cl_2[/tex]

1.20 mol = 5 x 1.2/2

              = 3 moles

In other words, 250 g [tex]PCl_5[/tex] will require 3 moles of [tex]Cl_2[/tex].

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Answer:

Explanation:

Here, we want to get the given definition

We have the solvent taking in as much solute as it can take

That is what we call a saturated solution

It simply means the amount of solute in the solvent is at the maximum

It is known that the three first alcohols are soluble in water, those are methanol, ethanol and propanol. It means that alcohols with less than 3 carbon atoms (methanol, ethanol) and with 3 carbon atoms (propanol) are soluble in water.

Therefore, the correct answer is Both A and B. The correct choice is D.

Step 1

The conservation of matter or mass is applied here. The same atoms must appear on both sides of the reaction.

The same number of atoms must appear on both sides of the reaction too.

---------------

Step 2

The reaction:

2 C2H6 + 7 O2 => 4 CO2 + 6 H2O (this is a combustion reaction)

The numbers next to the molecules are coefficients.

According to the question, the answer is:

2 C2H6

7 O2

4 CO2

6 H2O

CuSO4 + 5H2O → CuSO4 + H2O In this reaction addition of water takes place therefore this is a hydration reaction.

A chemical event called hydration occurs when two substances interact with water. Water is added to an unsaturated substrate in organic chemistry, which is often an alkene or an alkyne. The industrial production of ethanol, isopropanol, and butan-2-ol uses this sort of reaction.

Alkenes are often hydrated to produce alcohol, which is one of the most frequent hydration reactions.

While copper cannot conduct a displacement reaction with water, it may produce copper complexes through a redox/electrochemical reaction with water, oxygen.

Thus, this is hydration reaction.

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The first step to solve this question is to balance the given equation. To do it, make sure that the amount of every element is equal in both, reactants and products.

Now, use the stoichiometric ratio between the coefficients of potassium oxide and potassium nitride:

The answer is 4.66moles of magnessium nitride.

The question requires us to identify the molecular formula of a molecule formed between phosphorus (P) and chlorine (Cl).

The first step to solve this question is write the electronic configuration of both atoms involved (P and Cl) and, from the number of valence electrons, identify how many bonds each one should make.

P has atomic number 15, thus its electronic configuration is: 1s2 2s2 2p6 3s2 3p3

Cl has atomic number 17, thus its electronic configuration is: 1s2 2s2 2p6 3s2 3p5

Note that P has 5 valence electrons (3s2 and 3p3) while Cl has 7 valence electrons (3s2 3p5).

For P, we should expect 3 bonds to other atoms in order to reach the octet, while for Cl, we should expect 1 bond to another atom to achieve the octet.

With that in mind, we can say that each Cl will bond to one P, and we need 3 Cl. Therefore, the molecular formular is PCl3 (the last option).I

To determine the pH we can apply the equation for the pH of a solution:

pH = -log [H3O+]

Where [H3O+] is the molar concentration of the acid, so now we can apply the equation and do the respective operation:

The first shown ionic compound has only two elements, Li and F.

On a periodica table, we can see that Li is on the first group, so it is the metal one.

F is on the 17th group, so it is the nonmetal.

We have only one of each of them, so the formula will only have one of each.

The formula is:

And we have 1 of each, so their ratio is 1:1.

The equation for the synthesis of ammonia is:

N₂ + 3 H₂ ---> 2 NH₃

We have to find the number of moles of H₂ needed to produce 6 mol of NH₃. To do that we will use the equation that we were given.

We can read the equation of the reaction as a recipe. When 1 mol of N₂ reacts with 3 moles of H₂, 2 moles of NH₃ are produced. So the relationship between H₂ and NH₃ is that 3 moles of H₂ are needed to produce 2 moles of NH₃. We wiill use that relationship to solve the problem.

6 moles of NH₃ * 3 moles of H₂/(2 moles of NH₃) = 9 moles of H₂

Answer: D) 9 moles of H₂ are needed.

Answer

a. BeO

Explanation

The ionic compound formed from the elements beryllium and oxygen is beryllium oxide. The beryllium ion has a charge of +2 and has the symbol

Be²⁺. The oxide ion has a charge of -2 and has the symbol O²⁻.

Therefore, the correct formula for the compound from the elements beryllium and oxygen will be BeO

3. The leading cause of residencial fires (cooking equipment) is not the leading cause of residential death because the fire in the equipment can be extinguished in time, while the effects of smoking can remain unsigned in time.

4. The percentage of intentionally set fires is 8%. Someone might intentionally set a fire for example by burning yard trimmings.

5. There would be more structural fires in summer due to the high temperatures and the lack of rain.

In this question, we have to find the pH of 4 solutions with the given OH- concentration, and in order to do that, we have to find the pOH first, and then we can find the pH, the formula for pOH is the same as pH:

pOH = -log [OH-]

Solution 1:

pOH = -log [1.0*10^-2]

pOH = 2

pH + pOH = 14

pH = 14 - 2

pH = 12, this is a BASIC solution

Solution 2:

pOH = -log [1.0*10^-11]

pOH = 11

pH + pOH = 14

pH = 14 - 11

pH = 3, this is an ACIDIC solution

Solution 3:

pOH = -log [3.5*10^-2]

pOH = 1.45

pH + pOH = 14

pH = 14 - 1.45

pH = 12.55, this is a BASIC solution

Solution 4:

pOH = -log [4.4*10^-11]

pOH = 10.36

pH + pOH = 14

pH = 14 - 10.36

pH = 3.64, this is an ACIDIC solution