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3 years ago

I need help please this is due today

Chemistry

1 answer:

jonny [76]3 years ago

8 0

Option B is correct. Average speed can be found through the equation speed = distance/time. Applying this to each person using the data in the chart:

Dennis’ speed: 60 ft/0.5 secs = 120 ft per sec

Johnny’s speed: 60 ft/0.45 secs = 133.333 ft per sec

Travis’ speed: 60 ft/0.52 secs = 115.38 ft per sec

Michael’s speed: 60 ft/0.48 secs = 125 ft per sec

As you can see, Johnny’s speed is the fastest at 133.333 ft/sec.

You might be interested in

Find the potential energy of a 2 kg ball 15 m in the air.

amm1812

Answer:

294,3

Explanation:

$E=m*g*h$

While g = 9,81 m/s^2 then:

$E=2[kg]*9,81[\frac{m}{s^2} ]*15[m]=294,3 [J]$ [J]

7 0

3 years ago

An analysis showed there is 0.001 mol/L OH in a NaOH

tresset_1 [31]

40 ppm of NaOH

<u>Explanation:</u>

ppm is nothing but the parts per million and it is represented as 1 mg solute per kg of solution.

Here, number of moles of solute (NaOH) can be found as 0.001 mol / L, so we can find the amount of solute as,

Moles = $$\frac{mass of the solute }{ molar mass}$

0.001 mol / L = $$\frac{ mass of the solute}{40 g/ mol}$

0.001 × 40 = 0.04 g of solute

1 g = 1000 mg

0.04 g = 40 mg

In 1 kg of solution 40 mg of solvent is present.

So the concentration of NaOH is 40 ppm.

5 0

3 years ago

You will need to prepare 12 mL of 25% Sodium Phosphate Buffer (pH 4) solution for Activity 2. What volume of the stock Sodium Ph

zhuklara [117]

Assuming the concentration of stock solution is 50% sodium phosphate buffer solution, the volume of stock solution required is 6 mL and the volume of water required is 6 mL.

<h3>What volume of a stock Sodium phosphate buffer and water is needed to 12 mL of 25% sodium phosphate buffer of pH 4?</h3>

The process of preparing solutions from stock solutions of higher concentration is known as dilution.

Dilution is done with the aid of the dilution formula given below:

C1V1 = C2V2

where

C1 is the concentration of stock solution
V1 is the volume of stock solution required to prepare a diluted solution
C2 is the concentration of the diluted solution prepared
V2 is the final volume of the diluted solution

From the data provided:

C1 is not given

V1 is unknown

C2 = 25%

V2 = 12 mL

Assuming C1 is 50% solution

Volume of stock, V1, required is calculated as follows:

V1 = C2V2/C1

V1 = 25 × 12 /50

V1 = 6 mL

Therefore, the volume of stock solution required is 6 mL and the volume of water required is 6 mL.

Learn more about dilution formula at: brainly.com/question/7208546

6 0

2 years ago

(b) Which solution has a higher percent ionization of the acid, a 0.10M solution of HC2H3O2(aq) or a 0.010M solution of HC2H3O2(

boyakko [2]

Answer: The percent ionization is higher for 0.010 M solution of $HC_2H_3O_2$

Explanation:

$HC_2H_3O_2\rightarrow H^+C_2H_3O_2^-$

cM 0M 0M

$c-c\alpha$ $c\alpha$ $c\alpha$

So dissociation constant will be:

$K_a=\frac{(c\alpha)^{2}}{c-c\alpha}$

a) Given c= 0.10 M and $\alpha$ = ?

$K_a=1.8\times 10^{-5}$

Putting in the values we get:

$1.8\times 10^{-5}=\frac{(0.10\times \alpha)^2}{(0.10-0.10\times \alpha)}$

$(\alpha)=0.013$

$\%(\alpha)=0.013\times 100=1.3\%$

b) Given c= 0.010 M and $\alpha$ = ?

$K_a=1.8\times 10^{-5}$

Putting in the values we get:

$1.8\times 10^{-5}=\frac{(0.010\times \alpha)^2}{(0.010-0.010\times \alpha)}$

$(\alpha)=0.041$

$\%(\alpha)=0.041\times 100=4.1\%$

The percent ionization is higher for 0.010 M solution of $HC_2H_3O_2$

6 0

3 years ago

Do you think the tectonic plates are still moving today?why?

jek_recluse [69]

Yes, The tectonic plates are always moving and interacting today. The continents are still moving today. Because sometimes of the most dynamic sites of tectonic activity are seafloor spreading zones and giant rift valleys.

3 0

2 years ago