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2 years ago

The estimate obtained from a sample of which size is likely to be closest to

Chemistry

2 answers:

zubka84 [21]2 years ago

8 0

The answer is C, 85.

Leokris [45]2 years ago

5 0

the closest value is C, 85.

hope it helps!!!!

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Radioactive decay can be described by the following equation where is the original amount of the substance, is the amount of the

soldi70 [24.7K]

Answer:

Iron remains = 17.49 mg

Explanation:

Half life of iron -55 = 2.737 years (Source)

$t_{1/2}=\frac {ln\ 2}{k}$

Where, k is rate constant

So,

$k=\frac {ln\ 2}{t_{1/2}}$

$k=\frac {ln\ 2}{2.737}\ year^{-1}$

The rate constant, k = 0.2533 year⁻¹

Time = 2.41 years

$[A_0]$ = 32.2 mg

Using integrated rate law for first order kinetics as:

$[A_t]=[A_0]e^{-kt}$

Where,

$[A_t]$ is the concentration at time t

$[A_0]$ is the initial concentration

So,

$[A_t]=32.2\times e^{-0.2533\times 2.41}\ mg$

$[A_t]=32.2\times e^{-0.610453}\ mg$

$[A_t]=17.49\ mg$

Iron remains = 17.49 mg

8 0

2 years ago

Krypton-79 has a half-life of 35 hours. how many half-lives have passed after 105 hours?

Nookie1986 [14]

The number of half -lives that has passed after 105 hours for krypton-79 that has half-life of 35 hours is calculated as below

if 1 half life = 35 hours

what about 105 hours = ? half-lives

= (1 half life x105 hours) /35 hours = 3 half-lives has passed after 105 hours

6 0

2 years ago

Which statement correctly describes how the parts of a flowering plant contribute to its survival? A. Roots prepare the plant fo

bekas [8.4K]

Answer:

what

Explanation:

Which statement correctly describes how the parts of a flowering plant contribute to its survival? A. Roots prepare the plant for seed production, while the stem releases pollen for fertilization. B. Sepals prepare the plant for pollination, while the leaves collect oxygen for photosynthesis. C. Petals are involved in the reproductive cycle, while stamens protect the plant from predators. D. Ovaries are involved in fertilization and seed production, while anthers and

8 0

2 years ago

At 850 K, the equilibrium constant for the reaction

Sphinxa [80]

Answer:

Answers are in the explanation.

Explanation:

Given concentrations are:

SO₂ = 0.20M O₂ = 0.60M SO₃ = 0.60M

SO₂ = 0.14M O₂ = 0.10M SO₃ = 0.40M

And SO₂ = 0.90M O₂ = 0.50M SO₃ = 0.10M

In the reaction:

2SO₂(g) + O₂(g) ⇄ 2SO₃(g)

Kc is defined as:

Kc = 15 = [SO₃]² / [O₂] [SO₂]²

Where concentrations of each species are equilbrium concentrations.

Also, you can define Q (Reaction quotient) as:

Q = [SO₃]² / [O₂] [SO₂]²

Where concentrations of each species are ACTUAL concentrations.

If Q > Kc, the reaction will shift to the left until Q = Kc;

If Q < Kc, the reaction will shift to the right until Q = Kc

If Q = Kc, there is no net reaction because reaction would be en equilibrium.

Replacing with given concentrations:

Q = [0.60M]² / [0.60M] [0.20M]² = 15; Q = Kc → No net reaction

Q = [0.40M]² / [0.10M] [0.14M]² = 82; Q > Kc, → Reaction will shift to the left

Q = [0.10M]² / [0.50M] [0.90M]² = 0.015; Q < Kc → Reaction will shift to the right

8 0

2 years ago

Ta, Os, Th are from metal?

Alex787 [66]

Answer:

Tantalium is a Transition metal.

Osmium is a Transition metal.

Thorium is radioactive Metal.

6 0

2 years ago