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3 years ago

Question 4

Chemistry

1 answer:

mixer [17]3 years ago

5 0

Answer:

pH = 10.87

Explanation:

You can find pH of a buffer (Mixture of a weak base, X, and its conjugate acid, HX) by using H-H equation:

pH = pKa + log [X] / [HX]

pKb is -log Kb = 3.13

Using Hint pKw = pKa + pKb (pKw = 14)

pKw = pKa + pKb

14 - 3.13 = pKa

10.87 = pKa

Replacing in H-H equation:

pH = 10.87 + log [0.42M] / [0.42]

pH = 10.87 + log 1

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When determining the density of a pure liquid or solution the temperature of the sample must be measured what is the density of

Whitepunk [10]

Idk I just need points sorry man

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3 years ago

The nucleus’ pull on its electrons, taking into account any attractions weakened by shielding is called the:

Sever21 [200]

Answer:

It's called the shielding effect

Explanation:

It describes the decrease in attraction between an electron and the nucleus in any atom with more than one electron shell. (I hope this helps)

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2 years ago

Calculate the molar solubility of CaF2 at 25°C in a solution that is 0.010 M in Ca(NO3)2. The Ksp for CaF2 is 3.9 x 10-11.

madreJ [45]

Answer:

$Molar \ solubility=3.12x10^{-5}M$

Explanation:

Hello,

In this case, for the dissociation of calcium fluoride:

$CaF_2(s)\rightleftharpoons Ca^{2+}+2F^-$

The equilibrium expression is:

$Ksp=[Ca^{2+}][F^-]^2$

In such a way, via the ICE procedure, including an initial concentration of calcium of 0.01 M (due to the calcium nitrate solution), the reaction extent $x$ is computed as follows:

$3.9x10^{-11}=(0.01+x)(2*x)^2\\\\x=0.0000312M$

Thus, the molar solubility equals the reaction extent $x$ , therefore:

$Molar \ solubility=3.12x10^{-5}M$

Regards.

4 0

3 years ago

When .080 moles of propane burn at STP, what volume of carbon dioxide is produced?

ahrayia [7]

Taking into account the reaction stoichiometry and the definition of STP, 5.4 L of carbon dioxide is produced.

<h3>Reaction stoichiometry</h3>

In first place, the balanced reaction is:

C₃H₈ + 5 O₂ → 3 CO₂ + 4 H₂O

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

C₃H₈: 1 mole
O₂: 5 moles
CO₂: 3 moles
H₂O: 4 moles

<h3>Moles of CO₂ formed</h3>

The following rule of three can be applied: if by reaction stoichiometry 1 mole of C₃H₈ form 3 moles of CO₂, 0.080 moles of C₃H₈ form how many moles of CO₂?

$amount of moles of CO_{2} =\frac{0.080 moles of C_{3} H_{8}x3 moles of CO_{2} }{1 mole of C_{3} H_{8} }$

<u><em>amount of moles of CO₂= 0.24 moles</em></u>

<h3>Definition of STP condition</h3>

The STP conditions refer to the standard temperature and pressure. Pressure values at 1 atmosphere and temperature at 0 ° C are used and are reference values for gases. And in these conditions 1 mole of any gas occupies an approximate volume of 22.4 liters.

<h3>Volume of CO₂ produced</h3>

You can apply the following rule of three: If by definition of STP 1 mole of CO₂ occupies 22.4 L, 0.24 moles of CO₂ how much volume does it occupy?

$volume of CO_{2} =\frac{0.24 molesx22.4 L}{1 mole}$

<u><em>volume of CO₂= 5.376 L ≅ 5.4 L</em></u>

Finally, 5.4 L of carbon dioxide is produced.

Learn more about

the reaction stoichiometry:

<u>brainly.com/question/24741074</u>

<u>brainly.com/question/24653699</u>

STP conditions:

<u>brainly.com/question/26364483</u>

<u>brainly.com/question/8846039</u>

<u>brainly.com/question/1186356</u>

6 0

2 years ago

Which types of electron orbitals will have higher energy than a 4d orbital?

alexdok [17]

Answer:

D) 4f

Explanation:

To determine which electron orbital that will have higher energy than a 4d orbital, we write the electron configuration starting with s-orbital.

2s 2p

3s 3p 3d 3f

4s 4p 4d 4f

5s 5p 5d 5f

6s 6p 6d 6f

7s 7p 7d 7f

In ascending order, 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 3f, <u>4d</u><em>,</em> 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p, 6f, 7d, 7f.

From the electronic configuration formula above, the electron orbitals that have higher energy than a 4d orbital are 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p, 6f, 7d, 7f.

Therefore, 4f is the correct answer.

8 0

2 years ago