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Fudgin [204]
3 years ago
13

Which of the following happened first?

Chemistry
2 answers:
Liono4ka [1.6K]3 years ago
7 0
What do you mean which of the following happened first. You have to give the example
Alexxandr [17]3 years ago
4 0
Im sorry ma'am or sir you need to be more specific


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A hydrate of CoCl2 has a mass of 17.40 g before heating. After heating, the mass of the anhydrous compound is found to be 10.27
melisa1 [442]

Mass CoCl2 = 10.27 g
moles CoCl2 = 10.27 g/ 129.839 g/mol=0.07910

mass water = 17.40 - 10.27=7.13 g
moles water = 7.13 / 18.02 g/mol=0.396

0.396/ 0.07910=5

CoCl2 * 5 H2O

moles CaF2 = 85.8 g/ 78.0748 g/mol=1.10
moles Ca = 1.10
mass Ca = 1.10 x 40.078 g/mol=44.1 g
V = 44.1 / 1.55 =28.5 mL

Greetings!!
5 0
3 years ago
This decomposition is first order with respect to phosphine, and has a half‑life of 35.0 s at 953 K. Calculate the partial press
Solnce55 [7]

Answer:

0.57 atm

Explanation:

When a a reaction is first order, we have from calculus the following relation:

ln[A]t/[A]₀ = - kt

where [A]t is the concentration of A ( phosphine in this case ) after a time, t

           [A]₀ is the initial concentration of A

           k is the rate constant, and

           t is the time

We also know that for a first order reaction

           k = 0.693/ t 1/2

wnere t 1/2 is the half-life.

This equation is derived for the case when A]t/= 1/2 x [A]₀ which occurs at the half-life.

Thus, lets first find k from the half life time, and then solve for t = 70.5 s

k = 0.693 /  35.0 s = 0.0198 s⁻¹

ln [ PH₃ ]t / [ PH₃]₀ = - kt

from the ideal gas law we know pV = nRT, so the volumes cancel:

ln (pPH₃ )t / p(PH₃)₀ = - kt

taking inverse log to both sides of the equation:

(pPH₃ )t / p(PH₃)₀  = - kt

thus:

(pPH₃ )t  = 2.29 atm x e^(- 0.0198 s⁻¹ x 70.5 s ) = 0.57 atm

3 0
3 years ago
A particular chemical reaction is exergonic. What can you say about the relationship between the reactants and the products in t
ozzi

Answer:

Products have a lower total Gibbs free energy in comparison with the reagents total Gibbs free energy.

Explanation:

Hello,

Exergonic chemical reactions are those that the overall Gibbs free energy is negative, it means that the products have a lower total Gibbs free energy, turning out into a spontaneous chemical reaction. Such reactions are thermodynamically possible under standard conditions and they usually release heat.

Best regards.

7 0
3 years ago
In Part A, you found the amount of product (1.80 mol P2O5 ) formed from the given amount of phosphorus and excess oxygen. In Par
Finger [1]

First step is to balance the reaction equation. Hence we get P4 + 5 O2 => 2 P2O5

Second, we calculate the amounts we start with

P4: 112 g = 112 g/ 124 g/mol – 0.903 mol

O2: 112 g = 112 g / 32 g/mol = 3.5 mol

Lastly, we calculate the amount of P2O5 produced.

2.5 mol of O2 will react with 0.7 mol of P2O5 to produce 1.4 mol of P2O5.

This is 1.4 * (31*2 + 16*5) = 198.8 g

3 0
3 years ago
A sample of a substance has these characteristics: melting point of 984 K hard, brittle solid at room temperature poor conductor
ANEK [815]

The correct answer is option 4, that is, an ionic compound.  

The mentioned features belong to an ionic compound. The ionic compounds exhibit strong bonds in between their atoms, that is, an ionic bond is the strongest molecular bond, this confirms that ionic compounds exhibit a high melting point.  

The ionic compounds do not transmit current, as they do not possess free electrons, like metals, thus, they are poor conductors as solid. The ionic compounds get dissolve in water and form ions that are the charges, which can move, making them good conductors as a liquid. The composition of the ionic compound is a set of crystals that makes them brittle and hard.  

7 0
3 years ago
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