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3 years ago

7

Which of the following statements is true? Sound waves create areas of high and low pressure, Areas of high pressure are called

compressions. Areas of low pressure are called rarefactions. All of the above. .

1 answer:

ankoles [38]3 years ago

7 0

Answer:

all i think

Explanation:

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If you have a solution that contains 46.85 g of codeine, C18H21NO3, in 125.5 g of ethanol, C2H5OH, what is the mole fraction of

irakobra [83]

Answer:

0.22

Explanation:

Given, Mass of $C_{18}H_{21}NO_3$ = 46.85 g

Molar mass of $C_{18}H_{21}NO_3$ = 299.4 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$Moles= \frac{46.85\ g}{299.4\ g/mol}$

$Moles\ of\ C_{18}H_{21}NO_3= 0.1565\ mol$

Given, Mass of $C_{2}H_{5}OH$ = 125.5 g

Molar mass of $C_{2}H_{5}OH$ = 46.07 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$Moles= \frac{125.5\ g}{46.07\ g/mol}$

$Moles\ of\ C_{2}H_{5}OH= 0.5535\ mol$

So, according to definition of mole fraction:

$Mole\ fraction\ of\ codeine=\frac {n_{codeine}}{n_{codeine}+n_{ethanol}}$

$Mole\ fraction\ of\ codeine=\frac{0.1565}{0.1565+0.5535}=0.22$

4 0

2 years ago

. How many grams of NaOH would you need to make 450 mL of a 0.250 M NaOH solution

Stella [2.4K]

You have molarity and you have volume. Use the formula :
Molarity(M)= Moles(N)/Liter(L) to get the solution.
450 ml= .450 L
.250 = N/.450
N=.1125 moles of NaOH.
And since you know the moles, use the molar mass to figure out the grams.
<span> (40g/mol NaOH) x (.1125 mol) =
4.5g of NaOH.
</span>
Hope it helps. Good luck on chemistry.

7 0

3 years ago

Which block of elements do the halogens belong to?<br> a. p block<br> c. d block<br> b. s block?

kykrilka [37]

A. p block

from 3a-8a are in the p block including halogen

4 0

2 years ago

We are given that when θ = 38.7°, the angle of refraction in the liquid is θ = 26.3°. Thus, from Snell's law, the index of refra

oee [108]

Answer:1.4

Explanation:

Angle of incidence= 38°

Angle of refraction=26.3°

From Snell's law: n= sin i/sinr

sin i= 0.6157

sin r= 0.4430

n= 0.6157/0.4430=1.4

Note, n is dimensionless

5 0

2 years ago

How many moles of H2O are in 359 grams of H2O

solong [7]

Answer:

359

i think

Explanation:

4 0

2 years ago