1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
yuradex [85]
3 years ago
13

I need help please and thank you!!!

Chemistry
1 answer:
iragen [17]3 years ago
6 0

Answer:

-37

Explanation:

B=-7

D=9

therefore,

=4(B)-(D)

=4(-7)-(9)

=-28-9

=-37

You might be interested in
What is the equilibrium expression for the reatcion bellow<br><br> 2SO3(g)&lt;=&gt;O2(g)+2SO2(g)
Luda [366]

Answer:

[O2(g)][SO2(g)]^2/[SO3(g)]^2

8 0
3 years ago
determine the frequency and wavelength (in nm) of the light emitted when the e- fell from n=4 and n=2
Lostsunrise [7]

Answer:

Frequency = 6.16 ×10¹⁴ Hz

λ = 4.87×10² nm

Explanation:

In case of hydrogen atom energy associated with nth state is,

En =  -13.6/n²

For n = 2

E₂ = -13.6 / 2²

E₂ = -13.6/4

E₂ = -3.4 ev

Kinetic energy of electron = -E₂ = 3.4 ev

For n = 4

E₄ = -13.6 / 4²

E₄ = -13.6/16

E₄ = -0.85 ev

Kinetic energy of electron = -E₄ = 0.85 ev

Wavelength of radiation emitted:

E = hc/λ = E₄ - E₂

hc/λ = E₄ - E₂

by putting values,

6.63×10⁻³⁴Js × 3×10⁸m/s / λ = -0.85ev   - (-3.4ev )

6.63×10⁻³⁴ Js× 3×10⁸m/s / λ = 2.55 ev

λ = 6.63×10⁻³⁴ Js× 3×10⁸m/s  /2.55ev

λ = 6.63×10⁻³⁴ Js× 3×10⁸m/s  /2.55× 1.6×10⁻¹⁹ J

λ = 19.89 ×10⁻²⁶ Jm / 2.55× 1.6×10⁻¹⁹ J

λ = 19.89 ×10⁻²⁶ Jm / 4.08×10⁻¹⁹ J

λ = 4.87×10⁻⁷ m

m to nm:

4.87×10⁻⁷ m ×10⁹nm/1 m

4.87×10² nm

Frequency:

Frequency = speed of electron / wavelength

by putting values,

Frequency = 3×10⁸m/s /4.87×10⁻⁷ m

Frequency = 6.16 ×10¹⁴ s⁻¹

s⁻¹ = Hz

Frequency = 6.16 ×10¹⁴ Hz

3 0
3 years ago
Indicate if the following statements are TRUE (T) or FALSE (F):
Aleks [24]

Answer:

a) T

b) T

c) F

d) F

e) T

f) T

g) T

h) F

I) F

j) F

k) F

l) F

Explanation:

The w/v concentration is obtained from, mass/volume. Hence;

%w/v= 50/1000= 5%

In the %w/w we have;

25g/100 g = 25% w/w

In combustion reaction, energy is given out hence it is exothermic.

Neutralization reaction yields a salt and water

% by mass of carbon is obtained from;

8× 12/114 × 100 = 84.1%

All the ionic substances mentioned have very low solubility in water.

One mole of a substance contains the Avogadro's number of each atom in the compound.

There are two iron atoms so one mole contains 2× 55.85 g of iron.

Some sulphates such as BaSO4 are insoluble in water.

Halides are soluble in water hence NaI is soluble in water.

The equation does not balance with the given coefficients because the number of atoms of each element on both sides differ.

The equation represents a decomposition of calcium carbonate as written.

3 0
3 years ago
(6.022*10^23)*2.58=<br> what’s the answer
Sladkaya [172]
The answer would be
1.553676 \times  {10}^{24}
8 0
3 years ago
Read 2 more answers
What indicator of a chemical reaction could be measured using a thermometer?
Oksana_A [137]

Answer:

heat production

Explanation:

7 0
2 years ago
Other questions:
  • Hurry will mark brainliest Study this image of lithospheric plates.
    8·2 answers
  • What's the meaning of pH indicator?
    14·2 answers
  • Draw a structural formula for an alkyne of molecular formula c8h14 that yields 3-ethylhexane on catalytic hydrogenation. click t
    13·2 answers
  • If a gas occupies a volume of 950 mL at standard temperature, what volume will it
    14·1 answer
  • How is the sun classified​
    5·2 answers
  • A 7.32 g sample of copper is contaminated with 0.81 g of zinc. Suppose an atomic mass measurement was performed on this sample.
    10·1 answer
  • What do you expect will occur as air masses move over cold locations? Hot locations? How does this movement of air masses affect
    8·1 answer
  • Glaciers also _____ materials in new places when they melt.
    12·1 answer
  • The plant on the left is growing more because it has been receiving more water
    5·1 answer
  • PLSSS HEALP ASAP!!!! WILL REWARD
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!