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Agata [3.3K]
3 years ago
5

HELP ME!! THANH YOU If an atom has 80 protons and 121 neutrons, and is not in an excited state, how many electrons would Bohr sa

y the atom has? Select one: a. 41 b. 201 c. 121 d. 80
Chemistry
1 answer:
wariber [46]3 years ago
5 0
I think it might be 80
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Balance the chemical equation below: CO2 + H2O + 2678 kJ-> C6H1206 + O2 a. How many moles of H20 are involved in this reactio
11Alexandr11 [23.1K]

Answer:

a) 6 mol H2O

b) this reaction is endothermic

c) when 1 mol of CO2 is used, in the reaction they occur 0.5025 KJ

Explanation:

balanced eq:

  • 6CO2 + 6H2O + 2678 KJ ↔ C6H12O6 + 6O2

                                         6 - C - 6

                                         18 - O - 18

                                          12 - H - 12

a) mol H2O = 6 mol.......from balanced equation.

b) ΔE = 2678 KJ....... this reaction absorbs heat ( ΔE is positive )

c)    1 gramo C6H12O6 ≅ 4 cal

  • Mw C6H12O6 = 180.156 g/mol

⇒ 1mol CO2 * ( mol C6H12O6 / 6mol CO2 ) =0.166 mol C6H12O6

⇒ 0.166mol C6H12O6 * ( 180.156 g C6H12O6 / mol ) = 30.026g C6H12O6

⇒30.026 gC6H12O6 * ( 4 cal / gC6H12O6 ) * ( Kcal / 1000 cal ) * (4184 J / Kcal ) * ( KJ / 1000 J ) = 0.5025 KJ C6H12O6.

8 0
3 years ago
The cycling of carbon between the living and non-living parts of the Earth system is an important result of which of the followi
lesantik [10]

Answer:

b. Plants and animals exchanging gases with the atmosphere

Explanation:

5 0
2 years ago
Given the equation 4Al +3O2 --> 2Al2O3 if 325 grams of Al2O3 are to be formed, determine the mass of aluminum that must be re
den301095 [7]

Answer:

172 g Al

Step-by-step explanation:

We know we will need a balanced equation with masses and molar masses, so let’s <em>gather all the information</em> in one place.  

M_r:   26.98                101.96

            4Al + 3O₂ ⟶ 2Al₂O₃

m/g:                               325

(a) Calculate the <em>moles of Al₂O₃ </em>

n = 325 g Al₂O₃ × 1 mol Al₂O₃ /39.10 g Al₂O₃

n = 3.188 mol Al₂O₃

(b) Calculate the <em>moles of Al </em>

The molar ratio is (4 mol Al/2 mol Al₂O₃)

n = 3.188 mol Al₂O₃ × (4 mol Al/2 mol Al₂O₃)

n = 6.375 mol Al

(c) Calculate the <em>mass of Al</em>

m = 6.375 mol Al × (26.98 g Al/1 mol Al)

m = 172 g Al

Note: The answer can have only <em>three</em> significant figures because that is all you gave for the mass of Al₂O₃.

8 0
3 years ago
The longest day, and shortest night, of the year occurs on the
BaLLatris [955]

Answer:

This is the first answer,

winter solstice

The winter solstice occurs during the hemisphere's winter. In the Northern Hemisphere, this is the December solstice (usually December 21 or 22) and in the Southern Hemisphere, this is the June solstice (usually June 20 or 21).

and this is the second one,

the tilt of the Earth on its axis

Seasons change because of the tilt of the Earth and the planet's movement around the Sun. Did you know? It takes about 365.25 days for the Earth to orbit the Sun. We have leap years to make up for the extra ¼ day!

5 0
3 years ago
Which of the following types of mixtures exhibit the Tyndall effect?
Alekssandra [29.7K]
<span>C) <u>Colloids</u></span><span>

Colloids have small non-dissolved particles that flow around in the mixture. These particles do not settle over time. When a light is shined on colloids the scattering characteristic of the Tyndall effect are visable.</span>
4 0
3 years ago
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