All categories

3 years ago

Help me with 5-11 Reward - 15 points

Chemistry

2 answers:

NISA [10]3 years ago

6 0

5. is b
6. is c
7. is a
8. is d
9. is d
10.is d
11. is c

igor_vitrenko [27]3 years ago

5 0

5. C
6. C
7. B
8. B
9. A
10. A
11. D

You might be interested in

Plant use sunlight as energy to convert carbon dioxide and water into glucose and oxygen. Which best describes the reaction?

Illusion [34]

Answer:

Its the process of photosynthesis

8 0

3 years ago

Read 2 more answers

Chromium has an atomic mass of 51.9961 u and consists of four isotopes, 50 Cr , 52 Cr , 53 Cr , and 54 Cr . The 52 Cr isotope ha

Troyanec [42]

Answer : The atomic mass of $_{24}^{53}\textrm{Cr}$ isotope is 52.8367 amu

Explanation :

We know that:

Total percentage abundance of the isotope = 100 %

Percentage abundance of $_{24}^{50}\text{Cr}\text{ and }_{24}^{53}\textrm{Cr}\text{ isotopes}=[100-(83.79+2.37)]=13.84\%$

We are given:

Ratio of $_{24}^{50}\textrm{Cr}\text{ and }_{24}^{53}\textrm{Cr}$ isotopes = 0.4579 : 1

Percentage abundance of $_{24}^{50}\textrm{Cr}$ isotope = $\frac{0.4579}{(0.4579+1)}\times 13.84\%=4.37\%$

Percentage abundance of $_{24}^{53}\textrm{Cr}$ isotope = $\frac{1}{(0.4579+1)}\times 13.84\%=9.49\%$

Average atomic mass of an element is defined as the sum of masses of each isotope each multiplied by their natural fractional abundance.

Formula used to calculate average atomic mass follows: $\text{Average atomic mass }=\sum_{i=1}^n\text{(Atomic mass of an isotopes)}_i\times \text{(Fractional abundance})_i$ .....(1)

Let the mass of $_{24}^{53}\textrm{Cr}$ isotope be 'x'

For $_{24}^{50}\textrm{Cr}$ isotope:

Mass of $_{24}^{50}\textrm{Cr}$ isotope = 49.9460 amu

Percentage abundance of $_{24}^{50}\textrm{Cr}$ = 4.37 %

Fractional abundance of $_{24}^{50}\textrm{Cr}$ isotope = 0.0437

For $_{24}^{52}\textrm{Cr}$ isotope:

Mass of $_{24}^{52}\textrm{Cr}$ isotope = 51.9405 amu

Percentage abundance of $_{24}^{52}\textrm{Cr}$ isotope = 83.79 %

Fractional abundance of $_{24}^{52}\textrm{Cr}$ isotope = 0.8379

or $_{24}^{53}\textrm{Cr}$ isotope:

Mass of $_{24}^{53}\textrm{Cr}$ isotope = x amu

Percentage abundance of $_{24}^{53}\textrm{Cr}$ isotope = 9.49 %

Fractional abundance of $_{24}^{53}\textrm{Cr}$ isotope = 0.0949

For $_{24}^{54}\textrm{Cr}$ isotope:

Mass of $_{24}^{54}\textrm{Cr}$ isotope = 53.9389 amu

Percentage abundance of $_{24}^{54}\textrm{Cr}$ isotope = 2.37 %

Fractional abundance of $_{24}^{54}\textrm{Cr}$ isotope = 0.0237

Average atomic mass of chromium = 51.9961 amu

Putting values in equation 1, we get:

$51.9961=[(49.9460\times 0.0437)+(51.9405\times 0.8379)+(x\times 0.0949)+(53.9389\times 0.0237)]\\\\x=52.8367amu$

Hence, the atomic mass of $_{24}^{53}\textrm{Cr}$ isotope is 52.8367 amu

4 0

4 years ago

What is the pH of a 1.288 M solution of sodium acetate? Ka of acetic acid is 1.8*10^-5. (2 decimal places)

Shtirlitz [24]

Answer:

The pH of the solution is 9.43

Explanation:

sodium acetate = CH3COONa

after removing the spectator ion Na

CH3COO⁻ + H2O ⇄ CH3COOH + H3O⁺

since sodium acetate is a weak base, it will not react completely with water. Thus a value "x" will be used to make the products.

At equilibrium:

[CH3COO⁻] = 1.288 - x

[CH3COOH] = x

[H3O⁺] = x

Since a base is reacting with H2O, Kb is used at equilibrium: Kb=(1*10^-14)/(1.8*10^-5) = 5.6*10^-10)

Kb = [CH3COOH][H3O⁺]/[CH3COO⁻]

Kb = (x²)/(1.288-x) since the Kb is significantly lower than 1.288 we can make a mathematical assumption that x is significantly lower than 1.288.

5.6*10⁻¹⁰ = x²/1.288

x = [OH⁻] = 2.675*10⁻⁵ M

pOH = -log[OH⁻] = 4.57

pH=14-pOH = 14 - 4.57 = 9.43

4 0

3 years ago

What trend in ionization do you see going up and down?

xxTIMURxx [149]

Depending if you were going up, you would be seeing an increase in relative ionization energies in a particular group on the periodic table, and vice versa, if you go down the group, an decrease in the relative ionization energies.

5 0

3 years ago

A balloon is filled with 0.400 moles of gas. How many liters of gas at STP were pumped into the balloon?

Fynjy0 [20]

Answer:

8.96 L

Explanation:

At STP, 1 mole = 22.4 L

0.400 mole * (22.4 L. /1 mole of gas) = 8.96 L

3 0

4 years ago