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Alex787 [66]
4 years ago
10

Help please please please please

Chemistry
1 answer:
Rom4ik [11]4 years ago
7 0

Answer:

D. 18.7 grams

Explanation:

The coefficients are the key.

Create a proportion with them, and the molar mass, and then solve for x:

\frac{2}{3}  =  \frac{x}{28}  \\ 3x = 2(28) \\ 3x = 56 \\ x = 18.666... = 18.7

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The movement of one or more from one reactant to another is called
mrs_skeptik [129]

Answer: Redox Reaction

Explanation:

Redox reaction is the key chemical events in an oxidation-reduction also called Redox. It is the net movement of electrons from one reactants to another

7 0
3 years ago
Assuming equal concentrations and complete dissociation, rank these aqueous solutions by their freezing points. nh4cl cobr3 k2so
Illusion [34]
Answer: CoBr3 < K2SO4 < NH4 Cl

Justification:

1) The depression of the freezing point of a solution is a colligative property, which means that it depends on the number of particles of solute dissolved.

2) The formula for the depression of freezing point is:

ΔTf = i * Kf * m

Where i is the van't Hoof factor which accounts for the dissociation of the solute.

Kf is the freezing molal constant and only depends on the solvent

m is the molality (molal concentration).

3) Since, you are assuming equal concentrations and complete dissociation of the given solutes, the solute with more ions in the molecular formula will result  in the solution with higher depression of the freezing point (lower freezing point).

4) These are the dissociations of the given solutes:

a) NH4 Cl (s) --> NH4(+)(aq) + Cl(-) (aq) => 1 mol --> 2 moles

b) Co Br3 (s) --> Co(3+) (aq) + 3Br(-)(aq) => 1 mol --> 4 moles

c) K2SO4 (s) --> 2K(+) (aq) + SO4 (2-) (aq) => 1 mol --> 3 moles

5) So, the rank of solutions by their freezing points is:

CoBr3 < K2SO4 < NH4 Cl
4 0
3 years ago
Read 2 more answers
Which model of the atom is the most accurate
Zarrin [17]
Quantum Mechanical model (as per my knowledge)
7 0
3 years ago
What is the standard enthalphy change ΔHo, for the reaction represented above? (ΔHof of C2H2(g) is 230 kJ mol-1; (ΔHof of C6H6(g
wolverine [178]

Answer:

-608KJ/mol

Explanation:

3 C2H2(g) -> C6H6(g)

ΔHrxn = ΔHproduct - ΔHreactant

ΔHrxn= ΔHC6H6 - 3ΔHC2H2

ΔHrxn = 83 - 3(230)

ΔHrxn = -608

6 0
3 years ago
Electromagnetic radiation with a wavelength of 525 nm appears as green light to the human eye. The energy of one photon of this
Sedbober [7]

<u>Answer:</u> The energy of one photon of the given light is 3.79\times 10^{-19}J

<u>Explanation:</u>

To calculate the energy of one photon, we use Planck's equation, which is:

E=\frac{hc}{\lambda}

where,

\lambda = wavelength of light = 525nm=5.25\times 10^{-7}m        (Conversion factor:  1m=10^9nm  )

h = Planck's constant = 6.625\times 10^{-34}J.s

c = speed of light = 3\times 10^8m/s

Putting values in above equation, we get:

E=\frac{6.625\times 10^{-34}J.s\times 3\times 10^8m/s}{5.25\times 10^{-7}mm}\\\\E=3.79\times 10^{-19}J

Hence, the energy of one photon of the given light is 3.79\times 10^{-19}J

3 0
3 years ago
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