This is really confusing

Water flows over Niagara Falls at the average rate of 2,400,000 kg/s, and the average height of the falls is about 50 m. Knowing

Zinaida [17]

Answer:

1) The power of Niagara Falls is 1.176 × 10⁹ W

2) The number of 15 W LED light bulbs it could power is 78.4 × 10⁶ light bulbs

Explanation:

1) The Niagara falls water mass flow rate = 2,400,000 kg/s

The height of the fall = 50 meters

The gravitational potential energy = Mass (kg) × height (m) × gravity (9.8 m/s²)

The power = The energy converted per second = Mass flow rate (kg/s) × height (m) × gravity (9.8 m/s²)

Therefore;

The power of Niagara Falls= 2,400,000 kg/s × 50 m ×9.8 m/s²= 1.176 × 10⁹ W

The power of Niagara Falls = 1.176 × 10⁹ W

2) The number, n, of 15 W LED light bulbs it could power is given by the relation;

n × 15 W = 1.176 × 10⁹ W

∴ n = 1.176 × 10⁹ W/(15 W) = 78.4 × 10⁶ light bulbs

The number of 15 W LED light bulbs it could power = 78.4 × 10⁶ light bulbs.

6 0

3 years ago

A first-order reaction is 45% complete at the end of 43 minutes. What is the length of the half-life of this reaction

shtirl [24]

The half-life of the reaction is 50 minutes

Data;

Time = 43 minutes
Type of reaction = first order
Amount of Completion = 45%

<h3>Reaction Constant</h3>

Let the initial concentration of the reaction be X $_0$

The reactant left = (1 - 0.45) X $_0$ = 0.55 X $_0$ = X

For a first order reaction

$\ln(\frac{x}{x_o}) = -kt\\ k = \frac{1}{t}\ln (\frac{x_o}{x}) \\ k = \frac{1}{43}\ln (\frac{x_o}{0.55_o})\\ k = 0.013903 min^-^1$

The half-life of a reaction is said to be the time required for the initial amount of the reactant to reach half it's original size.

$x = \frac{x_o}{2} \\t = t_\frac{1}{2} \\t_\frac{1}{2} = \frac{1}{k}\ln(\frac{x_o}{x_o/2})\\$

Substitute the values

$t_\frac{1}{2} = \frac{1}{k}\ln(2)=\frac{0.6931}{0.013903}\\t_\frac{1}{2}= 49.85 min = 50 min$

The half-life of the reaction is 50 minutes

Learn more on half-life of a first order reaction here;

brainly.com/question/14936355

4 0

2 years ago

How does evolution work

sergey [27]

Billions of years ago, according to the theory of evolution, chemicals randomly organized themselves into a self-replicating molecule. This spark of life was the seed of every living thing we see today (as well as those we no longer see, like dinosaurs). That simplest life form, through the processes of mutation and natural selection, has been shaped into every living species on the planet.

4 0

3 years ago

Which of the following has the strongest buffering capacity? A. H2O B. 0.1 M HCl C. 0.1 M carbonic/bicarbonate (H2CO3/HCO3-) at

enyata [817]

Explanation:

(A) As we know that carbonic acid ( $H_{2}CO_{3}$ ) and Sodium bicarbonate ( $NaHCO_{3}$ ) forms an acidic buffer.

Therefore, pH of an acidic buffer is given by Hendeerson-Hasselbalch equation as follows.

pH = $pK_{a} + log(\frac{[Salt]}{[Acid]})$ ........... (1)

So mathematically, if [Salt] = [Acid] then $\frac{[Salt]}{[Acid]}$ = 1 .

And, $log (\frac{[Salt]}{[Acid]})$ = 0

Therefore, equation (1) gives us the following.

pH = $pK_{a}$ (when acid and salt are equal in concentration)

Hence, $pK_{a}$ of $H_{2}CO_{3}$ (carbonic acid) is 6.35.

And, with this we have following results.

In (A) and (D) we have the case \frac{[NaHCO_{3}]}{[H_{2}CO_{3}]}[/tex] i.e. [Salt] = [Acid].

Hence, for the cases pH = $pK_{a}$ = 6.35.

(B) $[NaHCO_{3}]$ = 0.045 M and, $[H_{2}CO_{3}]$ = 0.45 M

Hence, pH = $6.35 + log([NaHCO_{3}][[H_{2}CO_{3}])$

= $6.35 + log(\frac{0.045}{0.45})$

= 6.35 + (-1)

= 5.35

Therefore, it means that this buffer will be most suitable buffer as it has pH on acidic side and addition of slight excess base will not affect much of its pH value.

(C) $[NaHCO_{3}]$ = 0.45 M $[H_{2}CO_{3}]$

= 0.045 M

So, pH = $6.35 + log(\frac{[NaHCO_{3}]}{[H_{2}CO_{3}]})$