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Trava [24]
3 years ago
15

Identify the elements that have the following electron configurations: 1s²2s²2p⁶3s²3p⁶3d⁷4s² *

Chemistry
1 answer:
Leto [7]3 years ago
6 0
That would be calcium (Ca)
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In a reaction A --> B, when C is added it reacts irreversibly with A. What can we say about C? A. C will make the reaction sp
pav-90 [236]
The answer is C. For C, it can react irreversibly with A. That means when adding C, the concentration of A will decrease. For reaction A-->B. if A decrease, then the reaction rate will decrease.
8 0
3 years ago
Be sure to answer all parts. Consider the reaction 2SO2(g) + O2(g) ⇌ 2SO3(g)ΔH = −198.2 kJ/mol How would the concentrations of S
andrew-mc [135]

Answer:

a)

[SO2]: The concentration increases

[O2]: The concentration increases.

[SO3]: The concentration decreases.

b)

[SO2]: The concentration decreases.

[O2]: The concentration decreases.

[SO3]: The concentration increases.

c)

[SO2]:There is no change.

[O2]: There is no change.

[SO3]: There is no change

Explanation:

For an exothermic reaction, increase in temperature decreases the concentration of products and increases the concentration of reactants since increase in temperature shifts the equilibrium position to the left hand side.

Increase in pressure and decrease in volume will shift the equilibrium position towards the right hand side which means more SO3 in the system.

Catalyst increases the rate of forward and reverse reaction simultaneously hence at equilibrium, the concentration of reactants and products remain unchanged.

4 0
4 years ago
Calculate the molecular weight when a gas at 25.0 ∘C and 752 mmHg has a density of 1.053 g/L . Express your answer using three s
stiks02 [169]

Answer:

26.0 g/mol is the molar mass of the gas

Explanation:

We have to combine density data with the Ideal Gases Law equation to solve this:

P . V = n . R .T

Let's convert the pressure mmHg to atm by a rule of three:

760 mmHg ____ 1 atm

752 mmHg ____ (752 . 1)/760 =  0.989 atm

In density we know that 1 L, occupies 1.053 grams of gas, but we don't know the moles.

Moles = Mass / molar mass.

We can replace density data as this in the equation:

0.989 atm . 1L = (1.053 g / x ) . 0.082 L.atm/mol.K . 298K

(0.989 atm . 1L) / (0.082 L.atm/mol.K . 298K) = 1.053 g / x

0.0405 mol = 1.053 g / x

x =  1.053 g / 0.0405  mol = 26 g/mol

7 0
4 years ago
Aluminum metal reacts with aqueous cobalt(II) nitrate to form aqueous aluminum nitrate and cobalt metal. What is the stoichiomet
Lelu [443]

Answer:

the stoichiometric coefficient for cobalt is 3

Explanation:

the unbalanced reaction would be

Co(NO₃)₂+ Al → Al(NO₃)₃ + Co

One way to solve is to build a system of linear equations for each element (or group as NO₃) , knowing that the number of atoms of each element is conserved.

For smaller reactions a quick way to solve it can be:

- First the Co as product and as reactant needs to have the same stoichiometric coefficient

- Then the Al as product and as reactant needs to have the same stoichiometric coefficient

- After that we look at the nitrates . There are 2 as reactants and 3 as products . Since the common multiple is 6 then multiply the reactant by 3 and the product by 2.

Finally the balanced equation will be

3 Co(NO₃)₂+ 2 Al → 2 Al(NO₃)₃ + 3 Co

then the stoichiometric coefficient for cobalt is 3

7 0
4 years ago
At 25°C 12 M H202 is decomposed after 30 minutes the concentration of the H2O2 is found to be 9.5 M what is the average reaction
Bess [88]
The decomposition reaction of hydrogen peroxide:
2 H₂O₂(aq) →  2 H₂O(l) + O₂(g)
The order of reaction is : first order reaction.
[H₂O₂]₀ = 12 M at time = 0
[H₂O₂] = 9.5 M at time = 30 minutes
Average reaction rate = - (Δ[reactants] / Δt) 
                   = - (final reactants conc. - initial reactants conc.) / Δt
                   = - (9.5 M -12 M) / (30 min - 0 min) 
                   = 0.083 mol / L.min
8 0
3 years ago
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