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faust18 [17]
2 years ago
8

What is the mass of an original 5.60-gram sample of iron-53 that remains unchanged after 25.53 minutes? 0.35 g 0.70 g 1.40 g 2.8

0 g?
Chemistry
1 answer:
djverab [1.8K]2 years ago
3 0
Answer: 0.70g

The half-life of iron-53 would be 8.51 minutes. So, in 25.53 minutes would be equal to: 25.53 min/ (8.51 minutes/ half-life)= 3 half-life.

Every half-life will reduce the original weight into half. So, the final weight would be:
final weight = original weight * 1/2 ^(time)
final weight = 5.6g * (1/2)^(3 half-life)
final weight = 5.6g * 1/8= 0.7g
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What is the total mass of a mixture of 3.50x10^22 formula units na2so4, 0.500 mol h2o, and 7.23 g agcl?
Crazy boy [7]
Answer is: mass of the mixture is 24,47 g.
1) N(Na₂SO₄) = 3,5·10²².
n(Na₂SO₄) = 3,5·10²² ÷ 6·10²³ 1/mol.
n(Na₂SO₄) = 0,058 mol.
m(Na₂SO₄) = 0,058 mol · 142 g/mol.
m(Na₂SO₄) = 8,24 g.
2) n(H₂O) = 0,500 mol.
m(H₂O) = 0,5 mol · 18 g/mol.
m(H₂O) = 9 g.
3) m(total) = 8,24 g + 9 g + 7,23 g.
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n - amount of substance.
5 0
2 years ago
Analyze: The first shell can hold a maximum of two electrons. How does this explain the valence of hydrogen
chubhunter [2.5K]

Answer:

See explanation

Explanation:

Hydrogen has a valency of +1 or -1. Its electronic configuration is 1s1.

The 1s sub-level (first shell) is known to hold two electrons. This means that hydrogen may either loose this one electron in the 1s level to yield H^+ or accept another electron into this 1s level to form H^- (the hydride ion).

The formation of the hydride ion completes the 1s orbital.

4 0
2 years ago
The equilibrium constant, Kc, for the reaction H2 (g) + I2 (g) ⇄ 2HI (g) at 425°C is 54.8. A reaction vessel contains 0.0890 M H
Mars2501 [29]

Answer: The reaction is not at equilibrium and will proceed to make more products to reach equilibrium.

Explanation:  

Equilibrium constant is defined as the ratio of concentration of products to the concentration of reactants each raised to the power their stoichiometric ratios. It is expressed as K_{eq}

K is the constant of a certain reaction when it is in equilibrium, while Q is the reaction  quotient of activities of products and reactants at any stage other than equilibrium of a reaction.

For the given chemical reaction:

H_2(g)+I_2(g)\rightarrow 2HI(g)

The expression for Q is written as:

Q=\frac{[HI]^2}{[H_2]^1[I_2]^1}

Q=\frac{[0.0890]^2}{[0.215]^1[0.498]^1}

Q=0.074

Given : K_{eq} = 54.8

Thus as Q, the reaction will shift towards the right i.e. towards the product side.

4 0
2 years ago
What is the concentration of x2??? in a 0.150 m solution of the diprotic acid h2x? for h2x, ka1=4.5??10???6 and ka2=1.2??10???11
lutik1710 [3]
The first dissociation for H2X:
                        H2X +H2O ↔ HX + H3O
initial                0.15                     0      0
change             -X                     +X      +X
at equlibrium 0.15-X                  X        X
because Ka1 is small we can assume neglect x in H2X concentration
     Ka1      = [HX][H3O]/[H2X]
4.5x10^-6 =( X )(X) / (0.15)
X = √(4.5x10^-6*0.15) 
∴X = 8.2 x 10-4 m
∴[HX] & [H3O] = 8.2x10^-4
the second dissociation of H2X
        HX + H2O↔ X^2 + H3O
    8.2x10^-4          Y         8.2x10^-4
Ka2 for Hx = 1.2x10^-11
Ka2       = [X2][H3O]/[HX]
1.2x10^-11= y (8.2x10^-4)*(8.2x10^-4)
∴y = 1.78x10^-5
∴[X^2] = 1.78x10^-5 m


4 0
2 years ago
In the reaction 2Li(s) + 2H2O(l) 2LiOH(aq) + H2(g), what compound is in the gaseous state?
ipn [44]
Answer is: C. H₂, molecule of hydrogen, g is c<span>hemistry abbreviations or physical state symbol for gas.</span>
<span>
Lithium (Li) is solid (s) element (metal).
Water (H</span>₂O) is liquid (l) compound or molecule.
Lithium hydroxide (LiOH) is aqueous solution (aq). It dissociates in water on lithium cation (Li⁺) and hydroxy anion (OH⁻).
<span>


</span>
6 0
2 years ago
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