61. Using the symbol of the previous noble gas to indicate the core
electrons, write the electron configuration for each of the fol-
lowing elements.
a. scandium, Z= 21 c. lanthanum, Z= 57
b. yttrium, Z = 39
d. actinium, Z= 89

Answer:

D. 6.3 x 10-5 mol/L NaOH

Explanation:

Alizarin yellow is an indicator that is yellow when pH < 10.1. In the same way, thymol blue is blue when pH > 9

That means the pH of the solution is between 9 - 10.1

Any acid as HCl could have a pH of these.

The solution of 3.2x10⁻⁴M NaOH has a pH of:

pOH = -log[OH-] = 3.49

pH = 14-pOH = 10.51. The pH of the solution is not 10.5

Now, the solution of 6.3x10⁻⁵M NaOH has a pH:

pOH = -log[OH-] = 4.2

pH = 14-pOH = 9.8

The pH of the solution could be 9.8. Right option is:

Answer:

I hope that helps. I did not round the answer at the end. Maybe you want the final answer in a specific decimal place.

Answer:

[tex]P_2=6.0atm[/tex]

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to solve this problem by using the Boyle's law, since the temperature is constant and both volume and pressure change:

[tex]P_2V_2=P_1V_1[/tex]

Thus, we solve for the final pressure, P2, to obtain:

[tex]P_2=\frac{P_1V_1}{V_2}[/tex]

And plug in the given data to get:

[tex]P_2=\frac{2.0atm*12.0L}{4.0L}\\\\P_2=6.0atm[/tex]

Regards!

Answer:

Ka = 6.02x10⁻⁶

Explanation:

The equilibrium that takes place is:

We calculate [H⁺] from the pH:

Keep in mind that [H⁺]=[A⁻].

As for [HA], we know the acid is 0.66% dissociated, in other words:

We calculate [HA]:

Finally we calculate the Ka:

Answer:

in a solution with mass 30.55 grams, 4.25 grams is ethane

Option D is correct

Explanation:

Step 1: Data given

Volume of the solution = 50.0 mL = 0.05 L

Density of the solution = 0.611 m (g/mL)

mass % of the solution = 13.9 %

This means for every 100 grams of solution we have 13.9 grams of solute

Step 2: Calculate the mass of the solution

Density = mass/ volume

0.611 g/mL = mass of solution / 50.0 mL

Mass of the solution = 0.611 g/mL * 50.0 mL

Mass of the solution = 30.55 grams

Step 3: Calculate mass of ethane

Since the mass % = 13.9 % this means that there is 13.9 grams solute (ethane) for every 100 grams of solution

For a solution with mass 30.55 grams the mass of the solute (ethane) is:

(30.55/100)* 13.9 = 4.25 grams

This means that in a solution with mass 30.55 grams, 4.25 grams is ethane

Option D is correct

Answer: The heat absorbed by the water is 52.823 J.

Explanation:

Given: Mass of metal = 5.05 g

Specific heat of water = 4.184 [tex]J/g^{o}C[/tex]

Initial temperature = [tex]24.8^{o}C[/tex]

Final temperature = [tex]27.3^{o}C[/tex]

Formula used to calculate heat absorbed is as follows.

[tex]q = m \times C \times (T_{2} - T_{1})[/tex]

where,

q = heat

m = mass of substance

[tex]T_{1}[/tex] = initial temperature

[tex]T_{2}[/tex] = final temperature

Substitute the values into above formula as follows.

[tex]q = m \times C \times (T_{2} - T_{1})\\= 5.05 g \times 4.184 J/g^{o}C \times (27.3 - 24.8)^{o}C\\= 52.823 J[/tex]

Thus, we can conclude that heat absorbed by the water is 52.823 J.

Answer:

The correct answer is -

1. Latitude

2. Altitude

3. Bodies of water

4. Wind system

5. Amount of rainfall

Explanation:

Lattitude is the angle from the earth's equator towards the north or south to the poles. This is one of the important factors that lead to different seasons and define the temperature of the area.

Altitude is the elevation from the sea that also helps in affecting the seasons as the higher the altitude cooler the temperature. Water bodies like the sea affect the wind and climate as they are not able to absorb heat faster in comparison to the land.

Wind also affects the seasons and climate of the area as a large amount of warm air cools, it gives off  lots of rain over the land. Precipitation or rainfall determines and influences the climate.

Answer: If you want to make 10 moles of [tex]AlCl_{3}[/tex] then 30 moles of HCl are required in the given reaction.

Explanation:

The given reaction equation is as follows.

[tex]2Al + 6HCl \rightarrow 2AlCl_{3} + 3H_{2}[/tex]

Here, 6 moles of HCl reacts with 2 moles of [tex]AlCl_{3}[/tex]. This means that 1 mole of [tex]AlCl_{3}[/tex] is obtained as follows.

[tex]\frac{6}{2} HCl\\= 3 HCl[/tex]

Hence, 3 moles of HCl will give 1 mole of [tex]AlCl_3[/tex]. So, moles of HCl required to react with 10 moles of [tex]AlCl_{3}[/tex] is as follows.

[tex]1 mol AlCl_3 = 3 mol HCl\\10 mol AlCl_{3} = 3 \times 10 mol HCl\\= 30 mol HCl[/tex]

Thus, we can conclude that if you want to make 10 moles of [tex]AlCl_{3}[/tex] then 30 moles of HCl are required in the given reaction.

Answer:

Neutrons are all identical to each other, just as protons are. Atoms of a particular element must have the same number of protons but can have different numbers of neutrons.

Explanation:

Since the vast majority of an atom's mass is found its protons and neutrons, subtracting the number of protons (i.e. the atomic number) from the atomic mass will give you the calculated number of neutrons in the atom. In our example, this is: 14 (atomic mass) – 6 (number of protons) = 8 (number of neutrons).

Answer:

OH- is 1x 10^ + 3

Explanation:

- and - = +

Answer: The Ka expression for an aqueous solution of hypochlorous acid is [tex]K_{a} = \frac{[H_{3}O^{+}][OCl^{-}]}{[HClO]}[/tex].

Explanation:

The chemical formula of hypochlorous acid is HClO. So, when it is added to water (solvent) then its dissociation is as follows.

[tex]HClO + H_{2}O \rightarrow H_{3}O^{+} + Cl^{-}[/tex]

When we write the equilibrium constant for this reaction then it is called acid acid dissociated constant.

Hence, the expression for acid dissociation constant of this reaction is as follows.

[tex]K_{a} = \frac{[H_{3}O^{+}][OCl^{-}]}{[HClO]}[/tex]

Thus, we can conclude that the Ka expression for an aqueous solution of hypochlorous acid is [tex]K_{a} = \frac{[H_{3}O^{+}][OCl^{-}]}{[HClO]}[/tex].

Answer:

% yield = 200%

Explanation:

By using 145 gram of aluminium

Using 26.982 g/mol of Al, 101.96 g/mol of Aluminium oxide is produced

Using 145 grams of aluminium, the yield of Aluminium oxide  would have been = (101.96 g/mol/26.982 g/mol)/145 grams

= 547.9282485 gram

Now % yield = actual yield /theoretical yield * 100

Substituting the given values, we get -

% yield = (547.928/270) *100

% yield = 200%

Answer: The balanced equation is [tex]2SO_{2} + O_{2} + 2H_{2}O \rightarrow 2H_{2}SO_{4}[/tex].

Explanation:

A chemical equation which contains same number of atoms on both reactant and product side is called a balanced chemical equation.

For example, [tex]SO_{2} + O_{2} + H_{2}O \rightarrow H_{2}SO_{4}[/tex]

Here, number of atoms present on reactant side are as follows.

Number of atoms present on product side are as follows.

To balance this equation, multiply [tex]SO_{2}[/tex] by 2 and [tex]H_{2}O[/tex] by 2 on reactant side. Also, multiply [tex]H_{2}SO_{4}[/tex] by 2 on product side.

Hence, the equation can be re-written as follows.

[tex]2SO_{2} + O_{2} + 2H_{2}O \rightarrow 2H_{2}SO_{4}[/tex]

Now, the number of atoms present on reactant side are as follows.

Number of atoms present on product side are as follows.

Since, the atoms present on both reactant and product side are equal. Hence, the equation is now balanced.

Thus, we can conclude that the balanced equation is [tex]2SO_{2} + O_{2} + 2H_{2}O \rightarrow 2H_{2}SO_{4}[/tex].

Answer:

a. molecules that gain or lose an atom to develop a bonding charge

Explanation:

Answer:

See explanation and image attached

Explanation:

2‑methylhept‑3‑yne can be made by the reaction of the compound shown in the image attached with soidamide in liquid ammonia and 1‑bromopropane.

The first step in the reaction is the deprotonation of the alkyne starting material by the amide ion.

This step is followed a nucleophilic substitution reaction of the alkyne with 1‑bromopropane to yield the 2‑methylhept‑3‑yne product.

Answer:

Explanation:

The chemical reaction of the well-balanced equation is as follows:

[tex]\mathbf{2NiCl_{2(aq)}+2Na_2S_{(aq)} \to 4NaCl_{(aq)}+2NiS_{s}}[/tex]

The aforementioned reaction's ionic equation is:

[tex]\mathbf{2Ni^{2+}_{(aq)}+4Cl^-_{(aq)}+ 4Na^+_{(aq)}+2S^{2-}_{(aq)} \to 4Na^+_{(aq)}+4Cl^-_{(aq)}+2NiS_{(s)}}[/tex]

From above; Na⁺ and Cl⁻ appear on both sides;

Hence, the net ionic equation is:

[tex]\mathbf{2Ni^{2+}_{(aq)}+2S^{2-}_{(aq)} \to 2NiS_{(s)}}[/tex]

Explanation:

Magnesium reacts with dilute hydrochloric acid in a conical flask which is connected to an inverted measuring cylinder in a trough of water. The volume of hydrogen gas produced is measured over a few minutes, and the results are used to plot a graph

This is intended as a class practical. It is best if the students work in pairs because setting up and starting the experiment requires more than one pair of hands. One student can add the magnesium ribbon to the acid and stopper the flask, while the other starts the stopclock. During the experiment, one student can take the readings while the other records them. The experiment itself takes only a few minutes. But allow at least 30 minutes to give students time to set up, take readings and draw graph.

please mark as brainliest

Answer:

Chloroform.

Explanation:

Given,

Solvent requires 1g of compound per 100 mL

For water,

= 1g/47ml

= 2.1

For Chloroform,

= 1 g/8.1 mL

= 12.345679

For Diethyl ether,

= 1 g/370 mL

= 0.27

For Benzene,

=  1 g/86 mL

= 1.2

Partition coefficients:

Water = -

chloroform = 5.9

Diethyl = .13

Benzene  = .57

The solvent chloroform would be chosen for drawing out the compound out of an aqueous solution as it has the maximum solubility.

Answer:

Sodium arachidate; Sodium palmitate and Sodium palmitate

Explanation:

Triglycerides are esters of fatty acids with glycerol. In triglycerides, three fatty acid molecules are linked by ester bonds to each of the three carbon atoms in a glycerol molecule. The fatty acids may be same or different fatty acid molecules. Hydrolysis of triglycerides yields the three fatty acid molecules and glycerol.

Saponification is the process by which a base is used to catalyst the hydrolysis of the ester bonds in glycerides. The products of this base-catalyzed hydrolysis of triglycerides are the metallic salts of the three fatty acids and glycerol. The salts of the fatty acids are known as soaps.

For a triglyceride that has the fatty acid chains arachidic acid, palmitic acid and palmitic acid attached to the three backbone carbons glycerol, the saponification of the triglyceride with NaOH will yield the sodium salts or soaps of the three fatty acids as well as glycerol.

Arachidic acid will react with NaOH to yield sodium arachidate.

The two palmitic acid molecules will each react with NaOH to yield sodium palmitate.

Answer:

See explanation.

Explanation:

Hello there!

In this case, for this titration problem, we first need to set up the undergoing chemical equation between barium chloride and hydrochloric acid:

[tex]2HCl+Ba(OH)_2\rightarrow BaCl_2+2H_2O[/tex]

Which occurs in a 2:1 mole ratio of acid to base and thus, we can write the following:

[tex]2n_{base}=n_{acid}[/tex]

Which can be written in molarities and volumes:

[tex]2M_{base}V_{base}=M_{acid}V_{acid}[/tex]

And we solve for the molarity of the acid:

[tex]M_{acid}=\frac{2M_{base}V_{base}}{V_{acid}}[/tex]

Unfortunately, the molarity of the base was not given:

"The molarity of an aqueous solution of hydrochloric acid, , is determined by titration with a M barium hydroxide, , solution. If 31.2 mL of barium hydroxide are required to neutralize 15.4 mL of the acid, what is the molarity of the hydrochloric acid solution?"

Yet we can assume an arbitrary value, say 1.0 M in order to show you the solution so that you can modify it according to your given value:

[tex]M_{acid}=\frac{2(1.0M)(31.2mL)}{(15.4mL)}=4.05M[/tex]

So you just need to modify the (1.0 M) by the actually given molarity of the acid.

Regards!

Answer:

c = π/T*R

c = 0.199M

Explanation:

Is measured to be 5.1 atm at an absolute temperature of 312. K. Write an equation that will let you calculate the molarity c of this solution. Your equation should contain only symbols. Be sure you define each symbol other than R.

The osmotic pressure of a solution, π, is defined as:

π = c*T*R

As we know osmotic pressure π = 5.1atm, T = 312K and R = 0.082atmL/molK

we can replace in the equation as follows:

π= c*T*R

c = 5.1atm/312K*0.082atmL/molK

Answer:

=64.73..

Explanation:

0.750=5L

9.71=x

0.750*x÷0.750=5L*9.71÷0.750

x=48.55÷0.750

x=64.73..

Answer: For the given reaction [tex]Pb(NO_{3})_{2} + AlBr_{3}[/tex] the products are [tex]PBr_{2} + Al(NO_{3})_{3}[/tex].

Explanation:

A reaction in which two substances chemically combine together and results in the formation of a new substance is called a chemical reaction.

For example, [tex]3Pb(NO_{3})_{2} + 2AlBr_{3} \rightarrow 2Al(NO_{3})_{3} + 3PbBr_{2}[/tex]

Products are the species that are written on the right side of an arrow in a chemical reaction equation.

Hence, we can conclude that for the given reaction [tex]Pb(NO_{3})_{2} + AlBr_{3}[/tex] the products are [tex]PBr_{2} + Al(NO_{3})_{3}[/tex].

A distillation column is a process unit in which a feed mixture is separated by multiple partial vaporizations.

It should be noted that distillation simply means a process that has to do with the conversion of liquid into vapor.

In this case, distillation column is a process unit in which a feed mixture is separated by multiple partial vaporizations.

Learn more about distillation on:

brainly.com/question/24553469

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Answer:

136 KJ

Explanation:

We'll begin by calculating the heat required to melt the ice. This can be obtained as follow:

Mass (M) = 250 g

Heat of fusion (Hբ) = 334 J/gºC

Heat (Q₁) required to melt the ice =?

Q₁ = MHբ

Q₁ = 250 × 334

Q₁ = 83500 J

Next, we shall determine the heat required to change the temperature. This can be obtained as follow:

Mass (M) = 250 g

Initial temperature (T₁) = 0 °C

Final temperature (T₂) = 50 °C

Specific heat capacity (C) = 4.184 J/gºC

Heat (Q₂) required to change the temperature =?

Q₂ = MC(T₂ – T₁)

Q₂ = 250 × 4.184 (50 – 0)

Q₂ = 1046 × 50

Q₂ = 52300 J

Next, we shall determine the total heat required.

Heat (Q₁) required to melt the ice = 83500 J

Heat (Q₂) required to change the temperature = 52300 J

Total heat (Qₜ) required =?

Qₜ = Q₁ + Q₂

Qₜ = 83500 + 52300

Qₜ = 135800 J

Finally, we shall convert 135800 J to KJ. This can be obtained as follow:

1000 J = 1 KJ

Therefore,

135800 J = 135800 J × 1 KJ / 1000 J

135800 J ≈ 136 KJ

Thus, the total heat required is 136 KJ.