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2 years ago

Predict which of the following transition metal ions has a color Cr3+, Cd2+, Hg2+, V2+

Chemistry

2 answers:

ANEK [815]2 years ago

8 0

Answer:Cr3+ and V2+

Explanation:

Cd and Hg belong to group 12 which is sometimes referred to as post transition elements. They possess a filled d subshell (d10). Remember that the colour of transition elements is attributed to the presence of partially filled d orbitals leading to transition between the three degenerate lower energy t2g orbitals and two higher energy degenerate eg orbitals. If the element has a d10 configuration, such transition is impossible, hence its ions will be colourless.

Delicious77 [7]2 years ago

4 0

Answer:

Cr3+ is green and V2+ is purple. Cr3+ and V2+ are both d3 so there can be a lot of movement between energy levels to produce colored light. Cd2+ and Hg2+ are both d10 (full d orbital, much less electron movement).

Explanation:

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What is the pH of a Koh solution that has [H+]=1.87×10^-13M

xenn [34]

PH=-log[H⁺]
pH=-log(1.87×10⁻¹³)
pH=12.72

I hope this helps. Let me know if anything is unclear.

7 0

2 years ago

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The mass of sodium chloride in (g) is 14.19 The volume of ammonia solution in (mL) is 36.15 Calculate the following: What is the

Svetach [21]

This is an incomplete question, here is a complete question.

A weighed amount of sodium chloride is completely dissolved in a measured volume of 4.00 M ammonia solution at ice temperature, and carbon dioxide is bubbled in. Assume that sodium bicarbonate is formed util the limiting reagent is entirely used up. the solubility of sodium bicarbonate in water at ice temperature is 0.75 mol per liter. Also assume that all the sodium bicarbonate precipitated is collected and converted quantitatively to sodium carbonate.

Data to be used for calculating the results

-The mass of sodium chloride in (g) is 14.19

-The volume of ammonia solution in (mL) is 36.15

Calculate the following: What is the theoretical yield of sodium bicarbonate in grams?

Answer : The theoretical yield of sodium bicarbonate in grams is, 20.4 grams.

Explanation :

First we have to calculate the moles of NaCl and $NH_3$ .

$\text{ Moles of }NaCl=\frac{\text{ Mass of }NaCl}{\text{ Molar mass of }NaCl}=\frac{14.19g}{58.5g/mole}=0.243moles$

$\text{ Moles of }NH_3=\text{ Concentration of }NH_3\times \text{ Volume of solution}=4.00M\times 0.3615L=1.446moles$

Now we have to calculate the limiting and excess reagent.

The balanced chemical reaction will be:

$NH_3+NaCl+CO_2+H_2O\rightarrow NaHCO_3+NH_4Cl$

From the balanced reaction we conclude that

As, 1 mole of $NaCl$ react with 1 mole of $NH_3$

So, 0.243 mole of $NaCl$ react with 0.243 mole of $NH_3$

From this we conclude that, $NH_3$ is an excess reagent because the given moles are greater than the required moles and $NaCl$ is a limiting reagent and it limits the formation of product.

Now we have to calculate the moles of $NaHCO_3$

From the reaction, we conclude that

As, 1 mole of $NaCl$ react to give 1 mole of $NaHCO_3$

So, 0.243 moles of $NaCl$ react to give 0.243 moles of $NaHCO_3$

Now we have to calculate the mass of $NaHCO_3$

$\text{ Mass of }NaHCO_3=\text{ Moles of }NaHCO_3\times \text{ Molar mass of }NaHCO_3$

Molar mass of sodium bicarbonate = 84 g/mol

$\text{ Mass of }NaHCO_3=(0.243moles)\times (84g/mole)=20.4g$

Thus, the theoretical yield of sodium bicarbonate in grams is, 20.4 grams.

4 0

2 years ago

Using the periodic table entry of iron below, match the numbers with what they represent.

evablogger [386]

Answer:

Answers:

1. The number 26 ↔ atomic number

2. The number 56 ↔ mass number

3. The number 4 ↔ the number of orbits

4. The number 30 ↔ number of neutrons.

5. The number 14 ↔ number of electrons in n = 3

6. The number 2 ↔ number of valence electrons.

Explanation:

The same relevant information to deal with the data reported can be found in many periodic tables.

Herewith, I copy the mentioned entry. Please see the image attached.

This is the explanation of the information shown in the entry:

1) Symbol: in the centre of the picture: Fe. It is the symbol of iron.

2) Superscript to the lef of the symbol: 26. It is the atomic number, i.e. the number of protons. Hence, this is the first match:

1. The number 26 ↔ atomic number

3) The number 55.845 below the symbol and name of the element is the atomic mass of the element.

The atomic mass is the avereage mass of the several isotopes of the same element that exist in nature.

The particles that count for the atomic mass are the neutrons and protons, and that is reason of the called mass number, which is the sum of the neutrons and protons of a particular isotope.

An atomic mass of 55.845 means that likely there exist isotopes with mass number 56. This is, with a total number of 56 nucleons (protons and neutrons).

Since, as explained above, Fe has 26 protons, you can calcualte the number of neutrons of the 56 mass number isotope as: n = 56 - 26 = 30 neutrons.

Hence, you can match these:

2. The number 56 ↔ mass number

4. The number 30 ↔ number of neutrons

5. The numbers 2, 8, 14, and 2, that appear in the upper right corner of the image are the number of electrons in the different main energy levels, which is the principal quantum number (n)

They mean:

energy level (n) number of electrons

1 2

2 8

3 14

4 2

Hence you can match this:

5. The number 14 ↔ number of electrons in n = 3

6. The number 2 ↔ number of valence electrons

The valence electrons are the electrons in the last main energy level (here n = 4).

3. The number 4 ↔ the number of orbits

Note: orbits is not a good name for the energy levels, since orbits implies fixed paths around the nucleus and that is an overcome model.

3 0

2 years ago

Read 2 more answers

PLEASE HELP WITH THESE TWO QUESTIONS

adelina 88 [10]

1. Q=112.8 kJ

2. Q=5.01 kJ

<h3>Further explanation</h3>

The heat required for phase change :

melting/freezing :

Q = mLf

Lf=latent heat of fusion

vaporization/condensation

Q = mLv

Lv=latent heat of vaporization

m=50 g=0.05 kg

Lv (water) = 2256 kJ/kg

$\tt Q=0.05\times 2256=112.8~kJ$

m=15 g=0.015 kg

Lf for water = 334 kj/kg

$\tt Q=0.015\times 334=5.01~kJ$

3 0

2 years ago

Based on the name, which substance is a covalent compound?

jek_recluse [69]

Compounds that has two elements on the formula can be bonded by ionic or covalent bond. If the compound is a metal and a non-metal then it will be ionic bonding. However, when it involves two non-metals, then it will have covalent bonding.

3 0

2 years ago