Given:
BO3 + 3Mg → 3MgO + B
1. How many moles of Mg are required if 2 moles of B are produced?

Answer:

See explanation below

Explanation:

There are several ways to know if an acid or base is strong. One method is calculating the pH. If the pH is really low, is a strong acid, and if it's really high is a strong base.

However we do not have a pH value here.

The other method is using bronsted - lowry theory. If an acid is strong, then his conjugate base is weak. Same thing with the bases.

Now, Looking at the 4 compounds, we can say that only two of them is weak and the other two are strong compounds. Let's see:

LiOH ---> Strong. If you try to dissociate :

LiOH ------> Li⁺ + OH⁻     The Li⁺ is a weak conjugate acid.

HF -----> Weak

HF --------> H⁺ + F⁻   The Fluorine is a relatively strong conjugate base.

HCl -----> Strong

This is actually one of the strongest acid.

NH₃ ------> Weak

Now writting the Ka and Kb expressions:

Ka = [H⁺] [F⁻] / [HF]

Kb = [NH₄⁺] [OH⁻] / [NH₃]

Finally, to calculate the [OH⁻] we need to use the following expression:

Kw = [H⁻] [OH⁻]

Solving for [OH⁻] we have:

[OH⁻] = Kw / [H⁺]

Remember that the value of Kw is 1x10⁻¹⁴. So replacing:

[OH⁻] = 1x10⁻¹⁴ / 7x10⁻⁶

[OH⁻] = 1.43x10⁻⁹ M

And now, multiplying by 10¹⁰ we have:

[OH⁻] = 1.429x10⁻⁹ * 1x10¹⁰

Hope this helps

Strong acids and bases are those which completely ionized in body fluid, and weak acids and bases are those who does not completely ionized in body fluid.

Ka expression is used to differentiate between strong and weak acids.

[tex]\bold{\dfrac{[H+][F-]}{[HF]}}[/tex]

[tex]\bold{\dfrac{[NH_4^+] [OH^-]}{[NH_3]} }[/tex]

Given, [tex]\bold{ [H^+]=1\times10^-^6\; at \;25^oC}[/tex]

We know, [tex]\bold{ [H^+]\times[OH^-]=1\times10^-^6\; at \;25^oC}[/tex]

[tex]\bold{[OH^-]=\dfrac{1\times10^-^1^4}{6.2\times10^-^6} = 1.43\times10^-^9}[/tex]

Now, multiplying the value by [tex]10^1^0[/tex]

[tex]\bold{( 1.429\times10^-^9) \times 1\times10^1^0= 14.29}[/tex]

Thus, the value is 14.29.

Learn more about acid and base, here:

https://brainly.com/question/10468518

Answer:

iconic bond is the answer

I hope it helps you ✌

Answer: Energy of reactants = 30, Energy of products = 10

Exothermic

Activation energy for forward reaction is 10.

Explanation:

Exothermic reactions are defined as the reactions in which energy of the product is lesser than the energy of the reactants. The total energy is released in the form of heat and [tex]\Delta H[/tex] for the reaction comes out to be negative.

Energy of reactants = 30

Energy of products = 10

Thus as energy of the product < energy of the reactant, the reaction is exothermic.

Activation energy [tex](E_a)[/tex] is the extra energy that must be supplied to reactants in order to cross the energy barrier and thus convert to products.

[tex]E_a[/tex] for forward reaction is (40-30) = 10.

Answer:

B

Explanation:

Answer:

the change in energy when one substance dissolves in another

Explanation:

The enthalpy changes are the heat changes accompanying physical and chemical changes. Actually, an enthalpy change is the difference between the sum of the heat contents of products (final state) and sum of the heat contents of reactants (initial state).

There are basically two types of heat changes that accompanies are reaction which are:

Therefore, the change in energy when one substance dissolves in another defines the enthalpy of solution.

Enthalpy of solution is the heat liberated or absorbed when one mole of a substance (solute) is dissolved in a specified volume of solvent (water).

Answer:

Answer:

Reversible

Explanation:

Changes of state are physical changes in matter. Common changes of the state include melting, freezing, sublimation, deposition, condensation, and vaporization.

Answer:

See explanation

Explanation:

The valence electrons are electrons found on the valence (outermost) shell of an atom.

When an atoms form compounds, there is an exchange of valence electrons between the atoms of one element and the atoms of another element.

Let us consider a typical example, sodium has one valence electron and chlorine has seven valence electrons. This means that chlorine needs one electron to complete its octet while sodium needs to release one electron in order to attain the octet structure.

So, sodium gives out its one electron and becomes a stable sodium ion and chlorine accepts that electron and becomes a stable chloride ion. This is how the compound sodium chloride is formed.

The ocean is not a part of Earth's layers.

Answer:

Ocean

Explanation:

Answer:

25.8 g/dL

Explanation:

A chemist prepares a solution of aluminum sulfate by weighing out 116.0 g of aluminum sulfate into a 450. mL volumetric flask and filling the flask to the mark with water. Calculate the concentration in g/dL of the chemist's aluminum sulfate solution. Be sure your answer has the correct number of significant digits.

Step 1: Given data

Step 2: Convert "V" to dL

We will use the following conversion factors.

450. mL × 1 L/1000 mL × 10 dL/1 L = 4.50 dL

Step 3: Calculate the concentration (C) of aluminum sulfate if g/dL

We will use the following expression.

C = m/V = 116.0 g/4.50 dL = 25.8 g/dL

Answer: Equation 1, because Zn being more reactive, replaces Ag from AgNO3

Explanation: I got it right on the quiz and it replaces it

Answer:

A) 2

Explanation:

Answer:

2, i got it right thanks to the other user :) <3

Explanation:

Answer:

5.27 g of NaCl

Explanation:

The balanced equation for the reaction is given below:

Na₂CO₃ + CaCl₂ —> 2NaCl + CaCO₃

Next, we shall determine the mass of CaCl₂ that reacted and the mass of NaCl produced from the balanced equation. This can be obtained as follow:

Molar mass of CaCl₂ = 40 + (35.5×2)

= 40 + 71

= 111 g/mol

Mass of CaCl₂ from the balanced equation = 1 × 111 = 111 g

Molar mass of NaCl = 23 + 35.5

= 58.5 g/mol

Mass of NaCl from the balanced equation = 2 × 58.5 = 117 g

Summary:

From the balanced equation above,

111 g of CaCl₂ reacted to produce 117 g of NaCl.

Finally, we shall determine the theoretical yield of NaCl. This can be obtained as follow:

From the balanced equation above,

111 g of CaCl₂ reacted to produce 117 g of NaCl.

Therefore, 5 g of CaCl₂ will react to produce = (5 × 117)/111 = 5.27 g of NaCl.

Thus, the theoretical yield of NaCl is 5.27 g.

Answer:

0.41 atm

Explanation:

A reaction between liquid reactants takes place at 10.0 °C in a sealed, evacuated vessel with a measured volume of 5.0 L. Measurements show that the reaction produced 13. g of sulfur hexafluoride gas. Calculate the pressure of sulfur hexafluoride gas in the reaction vessel after the reaction. You may ignore the volume of the liquid reactants. Round your answer to 2 significant digits.

Step 1: Given data

Step 2: Convert "T" to Kelvin

We will use the following expression.

K = °C + 273.15

K = 10.0 °C + 273.15 = 283.2 K

Step 3: Calculate the moles (n) of SF₆

The molar mass of SF₆ is 146.06 g/mol.

13. g × 1 mol/146.06 g = 0.089 mol

Step 4: Calculate the pressure (P) of SF₆

We will use the ideal gas equation.

P × V = n × R × T

P = n × R × T/V

P = 0.089 mol × (0.0821 atm.L/mol.K) × 283.2 K/5.0 L = 0.41 atm

Answer:

What volume of water is produced when the CO2 reacts with the excess LiOH

X = 360 mL H2O

Explanation:

CO2 (g)       + 2 LiOH(s) ⇒ Li2CO3  (aq) + H2O(l)

20.0 mol        excess                                   x g

X = 360 mL H2O

x mL H20 = 20.0 mol CO2  (1 mol H2O /1 mol CO2)(18 g H2O/1 mol H2O)

(1 mL H2O /1 g H2O)

X = 360 mL H2O

Answer:

Molecules along the surface of a liquid behave differently than those in the bulk liquid.

Cohesive forces attract the molecules of the liquid to one another.

Water forming a droplet as it falls from a faucet is a primary example of surface tension.

Explanation:

Surface tension is the force that stretches the liquid surface. This force acts normal to the surface. It is the downward force that acts on the surface of the liquids which is due to the cohesive forces of the liquids.

The water molecules are bonded by a strong hydrogen bond force which is between hydrogen atom and the electronegative oxygen atom. At the surface the water molecules are attracted strongly by other water molecules which lies below the surface and are stretched at the surface. Thus the water molecules at the surface acts differently than in the bulk liquid.

Mercury have a strong cohesive force than the water and have a higher surface tension force than the water.

Surface water acquires minimum surface area, hence acquiring spherical shape of water.

Answer:

4

Explanation:

the one you ARE ON

Answer: 7.77 g/ml

Explanation:

Volume of cylinder with only water = 3.28 mL

Volume of cylinder with water and metal = 8.72 mL

Volume of metal = (Volume of cylinder with water and metal ) -(Volume of cylinder with only water)

=8.72-3.28

=5.44 ml

Mass of metal = 42.26 g

Formula of Density =  [tex]\dfrac{\text{Mass}}{\text{Volume}}[/tex]

i.e. the density of the metal = [tex]\dfrac{42.26}{5.44}\approx7.77\text{ g/ml}[/tex]

Hence, the density of metal = 7.77 g/ml

Answer:

Explanation:

The average kinetic energy for an ideal gas is directly proportional to the temperature. The average kinetic energy of the gas is a measure of the temperature of the gas molecule

Also, the average speed is usually proportional to the square root of temperature.

Similarly, there is a noticeable increase in K.E and speed in regard to temperature but sometimes it is not usually proportional.

However, provided that there is more temperature in Xe as compared to He, then after the mixture of both takes place at equilibrium; the temperature tends to fluctuate between (25 - 50)°C

Thus, since there is a decrease in temperature in Xe, both the average kinetic energy as well as the speed too will also decrease.

Answer:

[tex]\%N=26.2\%\\\\\%H=7.5\%\\\\\%Cl=66.3\%[/tex]

Explanation:

Hello!

In this case, since the calculation of the percent composition of an element in a chemical compound is computing considering its atomic mass, subscript in the formula and molecular mass of the compound it is; for nitrogen, hydrogen and chlorine we have that ammonium chloride has a molar mass of 53.49 g/mol so the percent compositions are:

[tex]\%N=\frac{14.01*1}{53.49}*100\% =26.2\%\\\\\%H=\frac{1.01*4}{53.49}*100\% =7.5\%\\\\\%Cl=\frac{35.45*1}{53.49}*100\% =66.3\%[/tex]

Best regards!

The temperature and the strength of the metallic link are the two most crucial variables that can impact how malleable a metal or alloy is.

A metal is a substance that has a shiny look when freshly processed, polished, or shattered, and conducts electricity and heat rather effectively. Generally speaking, metals are malleable and ductile.

The amount of pressure that a metal can sustain without breaking can be used to gauge its malleability. Varied metals have different degrees of malleability because of variations in their crystal structures.

The temperature of the metal and the strength of the metallic connection are the two parameters that define how malleable a metal or metal alloy will be.

Thus,  The kind of the metallic connection can have a significant impact on how easily metal atoms can rearrange themselves.

To learn more about metal, follow the link;

https://brainly.com/question/18153051

#SPJ2

Answer:

light

Explanation:

light is plasma, which is a state of matter

Answer:

No

Explanation:

This does not mean that vinegar is insoluble totally. In fact, vinegar is soluble in water because water is a polar solvent.

For a substance to be soluble in another, it must obey the rule of solubility.

The rule states that "like dissolves like"

It implies that polar solvent will only dissolve polar solute.

Also, non-polar solvent will only dissolve non-polar solute.

Therefore, the answer is no, vinegar will dissolve in water.

Answer:

i = 2.79

Explanation:

The excersise talks about the colligative property, freezing point depression.

Formula to calculate the freezing point of a solution is:

Freezing point of pure solvent - Freezing point of solution = m . Kf . i

Let's replace data given. (i = Van't Hoff factor, numbers of ions dissolved in solution)

48.1°C - 44°C = 0.15 m . 9.78°C/m . i

4.1°C / (0.15 m . 9.78°C/m) = i

i = 2.79

In this case, numbers of ions dissolved can decrease the freezing point of a solution, which is always lower than pure solvent.

Answer:

60.0mL of the diluted solution are needed

6.00mL of the 1.00M NaOH stock solution is the minimum volume needed to prepare the diluted solution.

Explanation:

As in each titration we need to use 20.0mL of the diluted 0.100M solution. As there are 3 titration, the volume must be:

3 * 20.0mL = 60.0mL of the diluted solution are needed

Now, to prepare a 0.100M NaOH solution from a 1.00M NaOH stock solution the dilution must be of:

1.00M / 0.100M = 10 times must be diluted the solution.

As we need at least 60.0mL, the minimum volume of the stock solution must be:

60.0mL / 10 times =

Answer:

c

Explanation:

ok than not c than b maybe

Answer:

Explanation:

From the given information:

The accuracy depends on the internal diameter of the cylinder. The cylinder with the least internal diameter is obviously more precise.

Let's assume 1% is the error of measurement.

Then, to measure 70 mL from 10 mL cylinder

The error = [tex]10 \times \dfrac{1}{100} \times 7[/tex]

= 0.7 mL

However; for a 100 mL cylinder, the error = 1 mL

Now,

The total volume for 10 mL = (70 + 0.7) = 70.7 mL

The total volume for 100 mL = (70 + 1 ) = 71 mL

Suppose the density (d) is same for both

Then;

the mass of 10 mL = ( d × 70.7) g

the mass pf 100 mL = (d × 71) g

Thus, the mass of 100 mL is greater than that of 10 mL.

Answer:

Partial pressures:

PCl₅ = 0.558 atm

PCl₃ = 0.22 atm

Cl₂ = 0.22 atm

Explanation:

From the given information:

The number of moles of PCl₅ associated with the evaporation is:

[tex]n_{PCl_5}= \dfrac {weight \ of \ PCl_5} {M.Wt. \ of \ PCl_5}[/tex]

[tex]n_{PCl_5}= \dfrac {2.69 \ g} {208.5 \ g/mol}[/tex]

[tex]n_{PCl_5}= 0.013 \ mol[/tex]

Temperature of the gas = 250° C = (250 + 273.15) K

= 523.15 K

Using the Ideal gas equation to determine the pressure exerted by the completely vaporized PCl₅

PV = nRT

[tex]P = \dfrac{nRT}{V}[/tex]

[tex]P = \dfrac{0.0013 \ mol \times 0.082 \ Latm^0 K^{-1} . mol ^{-1} \times 523.15 \ K}{1.0 \ L}[/tex]

P = 0.558 atm

Thus, at  250° C, decomposition of PCl₅ occurs.

In the container, PCl₅  decomposes to PCl₃ and Cl₂.

i.e.

[tex]PCl_{5(g)} \to PCl_{3(g)}+ Cl_{2(g)}[/tex]

Using Dalton's Law:

[tex]P_{total } =P_1 + P_2+P_3 +...[/tex]

[tex]P_1 = P_{Total} \times X_1[/tex]

where;

X = mole fraction

Then, the total no. of moles in the container is:

[tex]n = \dfrac{PV} {RT}[/tex]

[tex]n = \dfrac{1\ atm \times 1.0\ L}{0.0821 \ L \ atm \ K^{-1}.mol \times 523.15\ K}[/tex]

n = 0.023 mol

Now, the container contains a total amount of 0.023 mol where initially 0.013 mol are that of PCl₅ and remaining 0.005 mol of PCl₃ and 0.005 mol of Cl₂.

Thus, the partial pressure of  PCl₃  is:

[tex]P__{PCL_3} }= P_{total} \times \dfrac{no. \ of \ moles \ of PCl_5}{total \ no. \ of \ moles}[/tex]

[tex]P__{PCL_3}} = 1 \ atm \times \dfrac{0.005}{0.023}[/tex]

[tex]P__{PCL_3}} = 0.22 \ atm[/tex]

Thus, since the no of moles of PCl₃ and Cl₂ are the same, then the partial pressure for Cl₂ is = 0.22 atm

Answer:

e. I, At

Explanation:

Hello!

In this case, since the periodic trends of a series of elements belonging to the same group towards physical and chemical properties tend to be the same when closer in period, we notice that Mg and Al, Br and Kr and As and Br are close but in period, not in the same group; therefore e. I, At, iodine and astatine, are going to tend to exhibit the greatest similarity in their physical  and chemical properties.

Best regards!

Answer:

(a) 1s; has one orbital

(b) 4d; has five orbitals

(c) 3p; has three orbitals

(d) n=3 has nine orbitals

Explanation:

Electrons in an atom are always in constant motion, making it hard to predict there exact position. However, the most probable locations electrons can be be found are described with the terms shells, subshells and orbitals. A shell contains subshells and orbitals are found within subshells. The shells are given names such as K, L, M, N, which correspond to the principal quantum numbers, n = 1, 2, 3, and 4 respectively. There are 4 major types of subshells that can be found in a shell. They are named as s, p, d, f. Each subshell is composed of several orbitals.

a. 1s; the s subshell has only one orbital. Therefore, the 1s subshell has one orbital

b. 4d; the d subshell has five orbitals. Therefore, the 4d subshell has five orbitals

c. 3p; the p subshell has three orbitals. Therefore, the 3d subshell has  three orbitals

d. n = 3; the shell with n = 3 has the following subshells, 3s, 3p, 3d.the number of orbitals will be 1 + 3 + 5 = 9 orbitals. Therefore, the number of orbitals in n = 3 is nine orbitals