each year, one person in north america uses resources equal to how much land? A. 12 miles B. 12 acres C. 120 acres

Andrew [12]

Answer:

1977

Explanation:

Getting connected: a history of modems. Then, in 1977, Dale Heatherington and Dennis Hayes created the world's first PC modem, the 80-103A.

5 0

3 years ago

A student combines 364.6 g of HCl with 80 g of NaOH in 5 L of water. What additional volume of H2O must be added to this mixture

Jobisdone [24]

Answer:

75L of additional water to have a pH 1 solution

Explanation:

The reaction of HCl With NaOH is:

HCl + NaOH → H₂O + NaCl

By using molar mass of each reactant you can know how many moles will react, thus:

HCl: 364.6g HCl ₓ (1mol / 36.46g) = 10 moles HCl

NaOH: 80g NaOH ₓ (1mol / 40g) = 2 moles NaOH

That means after the reaction will remain in solution, 10-2 = 8 moles of HCl = 8 moles of H⁺ (In water, HCl dissociates as H⁺ and Cl⁻ ions).

A solution with pH = 1 contains:

pH = -log [H⁺]

1 = -log [H⁺]

0.1M = [H⁺]

As molarity, M is the ratio between moles and liters and you want a solution 0.1M having 8 moles of H⁺ you require:

0.1M = 8 moles H⁺ / 80L

As the student combines the solution with 5L of water, you require

<h3>75L of additional water to have a pH 1 solution</h3>

6 0

3 years ago

A house is built with a granite countertop. The heat capacity of the countertop is 158.5 kJ/°C. A hot pan of water is placed on

Svetlanka [38]

The temperature of the countertop changes by 0.032 °C

The quantity of heat transferred to the countertop is given by

Q = CΔT where Q = quantity of heat transferred to the countertop = 5000 J = 5 kJ, C = heat capacity of the countertop = 158.5 kJ/°C and ΔT = temperature change of the countertop.

Since we require the temperature change of the countertop, we make ΔT subject of the formula.

So, ΔT = Q/C

So, substituting the values of the variables into the equation, we have

ΔT = Q/C

ΔT = 5 kJ/158.5 kJ/°C

ΔT = 0.032 °C

So, the temperature of the countertop changes by 0.032 °C

Learn more about temperature change here:

brainly.com/question/16384350

8 0

3 years ago

A person weighs a different amount on other surfaces in space than they do on Earth because the gravitational pull of each surfa

Masja [62]

Answer:

A. The person weighs 56 pounds more on Mars than on the moon

Explanation:

7 0

3 years ago

Read 2 more answers

For the equilibrium

Mamont248 [21]

Answer:

Equilibrium concentrations of the gases are

$H_2S=0.596M$

$H_2=0.004 M$

$S_2=0.002 M$

Explanation:

We are given that for the equilibrium

$2H_2S\rightleftharpoons 2H_2(g)+S_2(g)$

$k_c=9.0\times 10^{-8}$

Temperature, $T=700^{\circ}C$

Initial concentration of

$H_2S=0.30M$

$H_2=0.30 M$

$S_2=0.150 M$

We have to find the equilibrium concentration of gases.

After certain time

2x number of moles of reactant reduced and form product

Concentration of

$H_2S=0.30+2x$

$H_2=0.30-2x$

$S_2=0.150-x$

At equilibrium

Equilibrium constant

$K_c=\frac{product}{Reactant}=\frac{[H_2]^2[S_2]}{[H_2S]^2}$

Substitute the values

$9\times 10^{-8}=\frac{(0.30-2x)^2(0.150-x)}{(0.30+2x)^2}$

By solving we get

$x\approx 0.148$

Now, equilibrium concentration of gases

$H_2S=0.30+2(0.148)=0.596M$

$H_2=0.30-2(0.148)=0.004 M$

$S_2=0.150-0.148=0.002 M$

3 0

3 years ago