could you calculate the percent composition for 15 and the empirical formal for 16

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

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.

[tex]{ \underline{ \red{ \sf{preparation \: f \: diborane}}}}[/tex]

Diborane is prepared by the reduction of boron trichloride with lithium aluminium hydride.

[tex]{ \blue{ \sf{4BF3 + 3LiAlH4 → 2B2H6 + 3AlF3 + 3LiF}}}[/tex]

It can be also prepared by reducing trifluoride with sodium hydride at 180°C.

[tex]{ \red{ \tt{2BF3 + 6NaH \: —(180°C)→ \: B2H6 + 6NaF}}}[/tex]

7.55 + 17.002 = ?

First, we have to determine the number of significant figures that each number has.

7.55: 3 SF and 2 SF after the decimal point.

17.002: 5 SF and 3 SF after the decial point.

Second, perform the mathematical operation as we usually do.

7.55 + 17.002 = 24.552

Finally we determine the correct number of SF. When adding or substracting the rule says: "The final answer may have no more SF after the decimal point than the least number of significant figures in the operation". Since 7.55 has 2 SF after the decimal point, we must round the result of the addition to the second place to the right of the decimal point.

Rounding 24.552 we get 24.55.

Answer: 24.55

The heat absorbed by the water is if the specific heat capacity of water is 4.184 J/g°C c)28,870J

It is given that the mass of water is 100g and temperature T₁ increases from 21°C to T₂ 90°C. The specific heat capacity of water(c) is 4.184g°C. To find the heat absorbed by the water, the following formula is used:

q = mcΔT

where, ΔT = T₂ - T₁

ΔT = 90 - 21

ΔT= 69°C.

Therefore, by substituting the values to the formula, we get the heat q as

q = 100x4.184x69

q = 418x69

q = 28870J

Therefore the heat absorbed by the water if the specific heat capacity of water is 4.184 J/g°C is 28,870J. Therefore the correct option is c)

To know more about specific heat capacity, click below:

https://brainly.com/question/13059309

#SPJ9

Answer:

Explanation;

Here, we want to get the number of moles in the given number of atoms

Mathematically:

The number of moles in the given number of atoms is thus:

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

To learn more about pH visit:

brainly.com/question/15289741

#SPJ9

Answer: 7 atoms

Explanation:

Answer:

5 atoms

Explanation:

Pb= 1 atom

N = 1 atom

O = 3 atoms

Thus, total no. of atoms are 5

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.

To learn more about hydration follow the link;

https://brainly.com/question/14027291?

#SPJ1

1) Molar concentration (Molarity). This concentration unit tells us the amount a solute per unit of volume.

M: Molar concentration

n: moles of solute

v: liters of solution

Mr. Orlin is incorrect because he used grams instead of moles.

2) Calculating the molarity of the solution

Convert grams of FeCl2 to moles

The molar mass of FeCl2 is 126.75 g/mol

Plug in known values

The concentration of a 0.45 L solution containing 200 g of iron (II) chloride is 3.507 M FeCl2.

.

Step 1 - Understanding what is a solution

A solution is a homogeneous mixture consisting of two or more substances: one solvent and two or more solutes. Even though water is the commonest of all solvents, it is not the only one. Alcohol can be a solvent as well, for example.

The solvent is usually defined as the substance present in the greatest amount.

Step 2 - Answering the question

The correct answer is item c) solvent, since the solvent is usually present in the greatest amount.

Answer:

197.12L of N2 are required.

Explanation:

1st) From the balanced reaction we know that 1 mol of N2 reacts with 3 moles of H2 to produce 2 moles of NH3.

2nd) It is necessary to convert moles to grams with the molar mass, and use the stoichiometry of the balanced reaction to find the amount of N2 moles that are required to produce 300g of NH3:

- N2 molar mass: 28g/mol

- NH3 molar mass: 17.01g/mol

300g of NH3 is equal to 17.64 moles of NH3.

3rd) Now, with a mathematical rule of three we can find the moles of N2 that are required to produce 17.64 moles of NH3:

Now we know that 8.82 moles of N2 are needed.

4th) Finally, using the molar volume value (22.4L), we can calculate the liters of N2 that are required.

The molar volume indicates that 1 mole is equivalent to a volume of 22.4L under normal conditions.

So, 197.12L of N2 are required.

Explanation:

To solve this question we use the following formula:

m = n*MM

m = mass

n = moles

MM = molar mass

MM of carbon s 12 g/mol

so:

m = 3.25*12

m = 39 g

Answer: 39 g

To balance a chemical equation, we have to take into account the coefficients and subscripts that indicate us the number of atoms of each element.

The first element we are going to balance is sodium, in the reactants, there is only one atom and in the products there two atoms of Na, so we have to assign 4 as the coefficient of NaOH and 2 as the coefficient of Na2HPO3.

There are 4 atoms of phosphorus in the reactants and 3 of them in the products. To balance it assign 2 as the coefficient of PH3.

Finally, balance the number of oxygens and hydrogens in the equation. There are 5 atoms of oxygen in the reactans and 6 of them in the products. Assign 2 as the coefficient of H2O, at this points, all the elements are balanced.

The balanced equation is:

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

Answer

The resulting solution will be neutral.

Explanation

Given:

Volume of HClO4 = 60.0 mL = 0.06 L

Molarity of HClO4 = 0.0500 M

Volume of NaOH = 40.0 mL = 0.04 L

Molarity of NaOH = 0.0750 M

What to find:

To determine if the resulting solution from (HClO4 and NaOH) acidic, basic, or neutral.

Solution;

The first step is to write a balanced chemical equation for the reaction.

HClO4 + NaOH → NaClO4 + H2O

The reaction is a neutralization reaction (also a double displacement reaction). The strong acid (HClO4) and a strong base react to produce salt (NaClO4) and water (H2O).

The next step is to determine the moles of the acid and the base using the formula below:

From the balanced chemical equation, 1 mol HClO4 neutralized 1 mol NaOH.

Therefore, 0.003 mol HClO4 will completely neutralize 0.003 mol NaOH and the resulting solution will be neutral.

Hydrochloric acid is a strong acid. This means that in a solution all the H+ ions will be released. Also, one mole of HCl has one hydrogen atom, so we can assume that the concentration of HCl is equal to the concentration of H+ ions.

On the other hand, the definition of pH tells us:

Where [H+] is the ions H+ concentration.

H+ concentration is 10^-4M. If we replace in the equation we will have:

answer: The pH of the solution is 4

Answer:

26.428 gm

Explanation:

molecular mass of CuFeS2 = 63.5+(2*32)+56 = 183.5 gm

Now we apply unitary method,

183.5 gm Chalcopyrite contains 56 gm Fe

∴ 86.6 gm Chalcopyrite contains [tex]\frac{56}{183.5} X 86.6[/tex]

                                                      = 26.428 gm Fe

0.518 mol L⁻¹ NaCl concentration results when 244 mL of a 0.750 M NaCl solution is mixed with 437 mL of a 0.390M NaCl solution.

Moles of NaCl  in 244ml = 244* 10⁻³L * 0.750 mol L⁻¹

= 183 * 10⁻³ mol

Moles of NaCl in 437ml = 437*10⁻³L * 0.390 mol L⁻¹

=170.43* 10⁻³ mol

Since we must consider the volumes to be additive when these solutions are mixed, we have the following concentration with respect to  NaCl

Concentration =  ( 0.183+ 0.170)mol/ (244+437)*10⁻³L

= 0.353 mol/681*10⁻³

= 0.518 mol L⁻¹

To know more about concentration

https://brainly.com/question/14547903

#SPJ1

3.16×10^23 molecules and 0.52 moles of caffeine are in the can.

given mass of caffeine=102 mg

molecular mass of caffeine=194.20 amu

moles=given mass/molecular mass

moles=102 mg/194.20 amu

moles= 0.52 mol

molecules = moles × avogadro number

molecules =0.52 mol× 6.022× 10^23

molecules=3.16×10^23 molecules

The mole signifies 6.02214076× 10^23 units, which is a very big quantity. The mole for the International System of Units is this quantity, according to the General Conference on Weights and Measures.

Every material has the same amount of atoms or other particles in a mole. The mole has the following relationship to an element's mass: One mole of carbon-12 atoms weighs 12 grams and has 6.02214076× 10^23 atoms.

To know more about  moles visit : https://brainly.com/question/26416088

#SPJ9

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

The balanced equation is:

The first step is to convert the given mass of magnesium to moles (MW=24.3g/mol):

Now, use the ratio given by the chemical equation:

Now, use the molecular weight of magnesium oxide to convert it to grams (MW=40.3g/mol):

The maximum mass of magnesium oxide produced is 1.612g.

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.

The mole fraction of a solute is the ratio of the number of moles of that solute to the total number of moles of the solution.

mole fraction of A = moles of A / total number of moles.

Option C and D are correct.

Electron affinity is dfined as the energy required to remove en electron from a gaseous atom or molecule. An example of a gaseous atom loosing an electron is given as:

From the reaction, you can see that the gaseous element X looses an electron from its outershell to form an ion. This reaction is known as the first electron affinity.

Hence the correct statement dealing with electron affinity are:

• It is the enthalpy change associated with the, removal of an electron, from a gaseous atom or ion.

• In general the, first electron affinity, is:, X(g) + e- → X-(g)

Answer: nonmetals, negative charge, more electrons than protons

Explanation:

162.75 g

So 1 mol of Pt contains 195.08 g, and 1 mol = 6.022*10^23 atoms, so when you do the math, you will have the value of 162.75 g of mass

6.022*10^23 = 195.08 g

5.024*10^23 = x grams

6.022*10^23x = 980.08

x = 980.08/6.022*10^23

x = 162.75 g

Explanation:

Structurally alcohols are alkanes with one H atom replaced by an -OH group. The main difference with diols is that they have two alcohol groups.

If we take for example the first row. The alcohol has 4 atoms of carbon, so its name is 1-butanol. In the same row, we are given a diol that only has 3 atoms of C (one less). Its name is 1,3-propanediol.

If we consider all the rows we will see that the main difference between the structures that we are given is that in each diol one atom of C is replaced by an alcohol group (-OH).

Answer: the main difference between the structures that we are given is that in each diol one atom of C is replaced by an alcohol group (-OH).

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.

learn more about temperature:

https://brainly.com/question/15194666

#SPJ1

Water property:

Water can moderate its temperature because of 2 properties: high specific heat and the high heat of vaporization.

High specific heat is the amount of energy that is absorbed or lost by one gram of a substance to change the temperature by 1 degree Celcius.

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

Water's high specific heat allows it to absorb a large amount of heat without changing much in temperature, keeping a relatively constant temperature.

Answer: a High specific heat capacity