All categories

4 years ago

A car slows down as it approaches a traffic light. Which best describes its acceleration?

Chemistry

2 answers:

svetoff [14.1K]4 years ago

8 0

The answer is B) Negative.

tino4ka555 [31]4 years ago

7 0

It's decelerating, so it's negative.

You might be interested in

How many moles are in 579 grams of Pt

aleksandr82 [10.1K]

2.96804 moles that’s the answer. hope it helped

6 0

4 years ago

Read 2 more answers

Write the equilibrium constant expression for this reaction: 2H+(aq)+CO−23(aq) → H2CO3(aq)

MrRissso [65]

Answer:

Equilibrium constant expression for $\rm 2\; H^{+}\, (aq) + {CO_3}^{2-}\, (aq) \rightleftharpoons H_2CO_3\, (aq)$ :

$\displaystyle K = \frac{\left(a_{\mathrm{H_2CO_3\, (aq)}}\right)}{\left(a_{\mathrm{H^{+}}}\right)^2\, \left(a_{\mathrm{{CO_3}^{2-}\, (aq)}}\right)} \approx \frac{[\mathrm{H_2CO_3}]}{\left[\mathrm{H^{+}\, (aq)}\right]^{2} \, \left[\mathrm{CO_3}^{2-}\right]}$ .

Where

$a_{\mathrm{H_2CO_3}}$ , $a_{\mathrm{H^{+}}}$ , and $a_{\mathrm{CO_3}^{2-}}$ denote the activities of the three species, and
$[\mathrm{H_2CO_3}]$ , $\left[\mathrm{H^{+}}\right]$ , and $\left[\mathrm{CO_3}^{2-}\right]$ denote the concentrations of the three species.

Explanation:

<h3>Equilibrium Constant Expression</h3>

The equilibrium constant expression of a (reversible) reaction takes the form a fraction.

Multiply the activity of each product of this reaction to get the numerator. $\rm H_2CO_3\; (aq)$ is the only product of this reaction. Besides, its coefficient in the balanced reaction is one. Therefore, the numerator would simply be $\left(a_{\mathrm{H_2CO_3\, (aq)}}\right)$ .

Similarly, multiply the activity of each reactant of this reaction to obtain the denominator. Note the coefficient " $2$ " on the product side of this reaction. $\rm 2\; H^{+}\, (aq) + {CO_3}^{2-}\, (aq)$ is equivalent to $\rm H^{+}\, (aq) + H^{+}\, (aq) + {CO_3}^{2-}\, (aq)$ . The species $\rm H^{+}\, (aq)$ appeared twice among the reactants. Therefore, its activity should also appear twice in the denominator:

$\left(a_{\mathrm{H^{+}}}\right)\cdot \left(a_{\mathrm{H^{+}}}\right)\cdot \, \left(a_{\mathrm{{CO_3}^{2-}\, (aq)}})\right = \left(a_{\mathrm{H^{+}}}\right)^2\, \left(a_{\mathrm{{CO_3}^{2-}\, (aq)}})\right$ .

That's where the exponent " $2$ " in this equilibrium constant expression came from.

Combine these two parts to obtain the equilibrium constant expression:

$\displaystyle K = \frac{\left(a_{\mathrm{H_2CO_3\, (aq)}}\right)}{\left(a_{\mathrm{H^{+}}}\right)^2\, \left(a_{\mathrm{{CO_3}^{2-}\, (aq)}}\right)} \quad\begin{matrix}\leftarrow \text{from products} \\[0.5em] \leftarrow \text{from reactants}\end{matrix}$ .

<h3 /><h3>Equilibrium Constant of Concentration</h3>

In dilute solutions, the equilibrium constant expression can be approximated with the concentrations of the aqueous " $(\rm aq)$ " species. Note that all the three species here are indeed aqueous. Hence, this equilibrium constant expression can be approximated as:

$\displaystyle K = \frac{\left(a_{\mathrm{H_2CO_3\, (aq)}}\right)}{\left(a_{\mathrm{H^{+}}}\right)^2\, \left(a_{\mathrm{{CO_3}^{2-}\, (aq)}}\right)} \approx \frac{\left[\mathrm{H_2CO_3\, (aq)}\right]}{\left[\mathrm{H^{+}\, (aq)}\right]^2\cdot \left[\mathrm{{CO_3}^{2-}\, (aq)}\right]}$ .

8 0

3 years ago

Why do surfers put wax on their boards

poizon [28]

Answer:

to keep the surfer from slipping off the board

Explanation:

Surfboard wax (also known as surfwax) is a formulation of natural and/or synthetic wax for application to the deck of a surfboard, bodyboard, or skimboard, to keep the surfer from slipping off the board when paddling out or riding a wave. It is also used to increase grip on the paddle of a surf kayak or dragon boat.

5 0

3 years ago

Read 2 more answers

Milk of magnesia is often taken to reduce the discomfort associated with acid stomach or heartburn. The recommended dose is 1 te

Igoryamba

Answer:

8.61 mL of the HCl solution

Explanation:

The reaction that takes place is:

2HCl + Mg(OH)₂ → MgCl₂ + 2H₂O

From the given mass of Mg(OH)₂, we can calculate <u>the moles of HCl that are neutralized</u>:

4x10² mg = 400 mg = 0.400g

0.400g Mg(OH)₂ ÷ 58.32g/1mol = 6.859*10⁻³ mol Mg(OH)₂

6.859*10⁻³ mol Mg(OH)₂ * $\frac{1molHCl}{1molMg(OH)_{2}} =$ 3.429x10⁻³ mol HCl

Finally, to calculate the volume of an HCl solution, we need both the moles and the concentration. We can <u>calculate the concentration using the pH value</u>:

pH = -log[H⁺]

1.4 = -log[H⁺]

$10^{-1.4}$ = [H⁺]

0.0398 M = [H⁺] = [HCl] *Because HCl is a strong acid*

Thus, the volume is:

0.0398 M = 3.429x10⁻³mol HCl / Volume

Volume = 8.616x10⁻³ L = 8.62 mL

6 0

4 years ago

Read 2 more answers

Which isotope of nirtogen is more abundent?

Jobisdone [24]

<span>Nitrogen-14 should be the correct response.</span>

6 0

4 years ago