When a substance changes from a solid to a liquid, is a new substance made?

A set of headphones produces sounds that cancel out sound waves from the

Basile [38]

Answer:

C. Destructive interference

Explanation:

Destructive interference is when there are two waves with the same frequency, and the peaks of one wave (the highest points) line up with the valleys (the lowest points) of the second one.

Constructive interference would cause the sound to be louder.

Absorption and reflection are interactions that would not take into account the fact that the headphones produce sounds.

4 0

3 years ago

Consider the single‑step, bimolecular reaction. CH3Br+NaOH⟶CH3OH+NaBr When the concentrations of CH3Br and NaOH are both 0.120 M

GarryVolchara [31]

Answer:

Explanation:

CH₃Br+NaOH⟶CH₃OH+NaBr

It is a single step bimolecular reaction so order of reaction is 2 , one for CH₃Br and one for NaOH .

rate of reaction = k x [CH₃Br] [ NaOH]

.008 = k x .12 x .12

k = .55555

when concentration of CH₃Br is doubled

rate of reaction = .555555 x [.24] [ .12 ]

= .016 M/s

when concentration of NaOH is halved

rate of reaction = .555555 x [.12] [ .06 ]

= .004 M/s

when concentration of both CH₃Br and Na OH is made 5 times

rate of reaction = .555555 x .6 x .6

= 0.2 M/s

8 0

3 years ago

Cho m gam FeO tác dụng hết với dung dịch H2SO4, thu được 200 ml dung dịch FeSO4 1M. Giá trị của m là

BaLLatris [955]

Answer: The mass of $FeO$ required is 14.37 g

Explanation:

Molarity is calculated by using the equation:

$\text{Molarity}=\frac{\text{Moles}}{\text{Volume}}$ ......(1)

We are given:

Molarity of iron (II) sulfate = 1 M

Volume of solution = 200 mL = 0.200 L (Conversion factor: 1 L = 1000 mL)

Putting values in equation 1, we get:

$\text{Moles of }FeSO_4=(1mol/L\times 0.200L)=0.200mol$

The chemical equation for the reaction of FeO with sulfuric acid follows:

$FeO+H_2SO_4\rightarrow FeSO_4+H_2O$

By stoichiometry of the reaction:

If 1 mole of iron (II) sulfate is produced by 1 mole of FeO

So, 0.200 moles of iron (II) sulfate will produce = $\frac{1}{1}\times 0.200=0.200mol$ of FeO

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

We know, molar mass of $FeO$ = 71.84 g/mol

Putting values in above equation, we get:

$\text{Mass of }FeO=(0.200mol\times 71.84g/mol)=14.37g$

Hence, the mass of $FeO$ required is 14.37 g

4 0

3 years ago

66.0g of dry ice (solid carbon dioxide)

d1i1m1o1n [39]

Answer:

Dry Ice is frozen CO2

Explanation:

we just need to convert the 10g into moles

Carbon has atomic mass of 12, and oxygen has atomic mass of 16, so molar mass = 12 + 16(2)= 44

Do 66/44 to get the moles = 1.5 (ans)

3 0

3 years ago

Calculate the pH of a solution that is 0.235M benzoic acid and 0.130M sodium benzoate, a salt whose anion is the conjugate base

lesantik [10]

Hello!

We have the following data:

ps: we apply Ka in benzoic acid to the solution.

[acid] = 0.235 M (mol/L)

[salt] = 0.130 M (mol/L)

pKa (acetic acid buffer) =?

pH of a buffer =?

Let us first find pKa of benzoic acid, knowing that Ka (benzoic acid) = $6.20*10^{-5}$

So:

$pKa = - log\:(Ka)$

$pKa = - log\:(6.20*10^{-5})$

$pKa = 5 - log\:6.20$

$pKa = 5 - 0.79$

$\boxed{pKa = 4.21}$

Now, using the abovementioned data for the pH formula of a buffer solution or (Henderson-Hasselbalch equation), we have:

$pH = pKa + log\:\dfrac{[salt]}{[acid]}$

$pH = 4.21 + log\:\dfrac{0.130}{0.235}$

$pH = 4.21 + log\:0.55$

$pH = 4.21 + (-0.26)$

$pH = 4.21 - 0.26$

$\boxed{\boxed{pH = 3.95}}\end{array}}\qquad\checkmark$

Note:. The pH <7, then we have an acidic solution.

I Hope this helps, greetings ... DexteR! =)

8 0

2 years ago