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3 years ago

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1. One of my goals is to get 8 hours of sleep a night. If I sleep 7,259,102 second, how many hours of sleep is that (w/ proper s

ig figs)?
2. Did I meet my goal?
3. How many seconds are in 8.0000 hours?

1 answer:

soldier1979 [14.2K]3 years ago

7 0

Answer:

2016.417222 hours

Explanation: you def made your goal

28800 seconds

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Picric acid has been used in the leather industry and in etching copper. However, its laboratory use has been restricted because

olchik [2.2K]

Answer:

0.3023 M

Explanation:

Let Picric acid = $H_{picric}$

So, $H_{picric}$ + $H_2}O$ ⇄ $H_3}O^+$ + $Picric^-$

The ICE table can be given as:

$H_{picric}$ + $H_2}O$ ⇄ $H_3}O^+$ + $Picric^-$

Initial: 0.52 0 0

Change: - x + x + x

Equilibrium: 0.52 - x + x + x

Given that;

acid dissociation constant ( $K_a$ ) = 0.42

$K_a = \frac{[H_3O^+][Picric^-]}{H_{picric}}$

$0.42 = \frac{[x][x]}{0.52-x}}$

$0.42 = \frac{[x]^2}{0.52-x}}$

0.42(0.52-x) = x²

0.2184 - 0.42x = x²

x² + 0.42x - 0.2184 = 0 -------------------- (quadratic equation)

Using the quadratic formula;

$\frac{-b+/-\sqrt{b^2-4ac} }{2a}$ ; ( where +/- represent ± )

= $\frac{-0.42+/-\sqrt{(0.42)^2-4(1)(-0.2184)} }{2*1}$

= $\frac{-0.42+/-\sqrt {0.1764+0.8736} }{2}$

= $\frac{-0.42+\sqrt {1.0496} }{2}$ OR $\frac{-0.42-\sqrt {1.0496} }{2}$

= $\frac{-0.42+1.0245}{2}$ OR $\frac{-0.42-1.0245}{2}$

= $\frac{0.6045}{2}$ OR $-\frac{1.4445}{2}$

= 0.30225 OR - 0.72225

So, we go by the +ve integer that says:

x = 0.30225

x = [ $H_3}O^+$ ] = [ $Picric^-$ ] = 0.3023 M

∴ the value of [H3O+] for an 0.52 M solution of picric acid = 0.3023 M (to 4 decimal places).

6 0

3 years ago

One of the radioactive isotopes used in medical treatment or analysis is chromium-51. The half-life of chromium-51 is 28 days. H

Goryan [66]

Answer : The time required for decay is, 84 days.

Explanation :

Half-life of chromium-51 = 28 days

First we have to calculate the rate constant, we use the formula :

$k=\frac{0.693}{t_{1/2}}$

$k=\frac{0.693}{28\text{ days}}$

$k=0.0248\text{ days}^{-1}$

Now we have to calculate the time required for decay.

Expression for rate law for first order kinetics is given by:

$t=\frac{2.303}{k}\log\frac{a}{a-x}$

where,

k = rate constant

t = time taken by sample = ?

a = let initial activity of the sample = 100

a - x = amount left after decay process = 12.5

Now put all the given values in above equation, we get

$t=\frac{2.303}{0.0248}\log\frac{100}{12.5}$

$t=83.9\text{ days}\approx 84\text{ days}$

Therefore, the time required for decay is, 84 days.

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3 years ago

Kinetic energy is energy that an object possesses because of its

uysha [10]

Kinetic energy is the energy possessed by an object due to its motion. If an object is moving, then it has kinetic energy. If an object has kinetic energy, then it is moving. Many students confuse kinetic energy with potential energy.

4 0

3 years ago

The molar solubility of calcium sulfide in a 0.222 M sodium sulfide solution is:________-

timurjin [86]

Sorry I don’t get the question Buh I’m sure you’ll get it eventually

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3 years ago

A 350.0 ml sample of gas has a temperature of 22.7 C and a pressure of 0.914 atm. What temperature would be needed for the same

Rus_ich [418]

Answer:

Explanation:

We shall apply gas law formula

P₁ V₁ / T₁ = P₂V₂ / T₂

.914 x 350 / ( 273 + 22.7 ) = 1 x 220 / T₂

1.0818 = 220 / T₂

T₂ = 203.36 K

= - 69.64 ⁰ C

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3 years ago