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aleksandrvk [35]
2 years ago
7

PLEASE ANSWER ASAP NEED ANSWER!!!!!!!!!!!!!! 75 POINTS

Chemistry
2 answers:
kakasveta [241]2 years ago
5 0

Answer:

The answer to your question is A.

Pure substances can not be broken down into others, so they cannot be molecules

Explanation:

neonofarm [45]2 years ago
3 0

Answer:

<u>D. All pure substances are molecules.</u>

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The ph of a solution containing 0.818 M acetic acid<br> (ka1.76*10-5) ans 0.172 M sodium acetate is?
kvasek [131]

Explanation:

It is known that the relation between pH and pK_{a} is as follows.

              pH = pK_{a} + log \frac{[salt]}{[acid]}

and,     pK_{a} = -log K_{a}

Hence, first we will calculate the value of pK_{a} as follows.

                   pK_{a} = -log K_{a}

                               = -log (1.76 \times 10^{-5}

                               = 4.75

Now, we will calculate the value of pH as follows.

              pH = pK_{a} + log \frac{[\text{sodium acetate}]}{\text{acetic acid}}

                    = 4.75 + log \frac{0.172}{0.818}      

                    = 4.75 + (-0.677)

                    = 4.07

Therefore, we can conclude that the pH of given solution is 4.07.

5 0
3 years ago
What is the pH of a solution that is 0.40 M NaBrO and 0.50 M HBrO (hypobromous acid) (Ka for HBrO = 2.3 x 10^-9)
Pie

Answer

pH=8.5414

Procedure

The Henderson–Hasselbalch equation relates the pH of a chemical solution of a weak acid to the numerical value of the acid dissociation constant, Kₐ. In this equation, [HA] and [A⁻] refer to the equilibrium concentrations of the conjugate acid-base pair used to create the buffer solution.

pH = pKa + log₁₀ ([A⁻] / [HA])

Where

pH = acidity of a buffer solution

pKa = negative logarithm of Ka

Ka =acid disassociation constant

[HA]= concentration of an acid

[A⁻]= concentration of conjugate base

First, calculate the pKa

pKa=-log₁₀(Ka)= 8.6383

Then use the equation to get the pH (in this case the acid is HBrO)

pH=8.6383+\log_{10}(\frac{0.40\text{ M}}{0.50\text{ M}})=8.5414

8 0
1 year ago
4.3 moles of a gas are at a temperature of 28 degrees * C with a pressure of 1.631 atm. What volume does the gas occupy?
Shkiper50 [21]

Answer:

65.2L

Explanation:

Using the general gas equation;

PV = nRT

Where;

P = pressure (atm)

V = volume (Litres)

n = number of moles (mol)

R = gas law constant (0.0821 Latm/molK)

T = temperature (Kelvin)

According to the information provided in this question,

P = 1.631 atm

V = ?

n = 4.3 moles

T = 28°C = 28 + 273 = 301K

Using PV = nRT

V = nRT/P

V = 4.3 × 0.0821 × 301 ÷ 1.631

V = 106.26 ÷ 1.631

V = 65.15

Volume of the gas = 65.2L

7 0
2 years ago
The rate constant for a certain reaction is k = 5.40×10−3 s−1 . If the initial reactant concentration was 0.100 M, what will the
IceJOKER [234]

Answer : The concentration after 17.0 minutes will be, 4.05\times 10^{-4}M

Explanation :

The expression for first order reaction is:

[C_t]=[C_o]e^{-kt}

where,

[C_t] = concentration at time 't'  (final) = ?

[C_o] = concentration at time '0' (initial) = 0.100 M

k = rate constant = 5.40\times 10^{-3}s^{-1}

t = time = 17.0 min = 1020 s (1 min = 60 s)

Now put all the given values in the above expression, we get:

[C_t]=(0.100)\times e^{-(5.40\times 10^{-3})\times (1020)}

[C_t]=4.05\times 10^{-4}M

Thus, the concentration after 17.0 minutes will be, 4.05\times 10^{-4}M

4 0
3 years ago
When the Earth rotates, what happens to the constellations?
kobusy [5.1K]

Answer:

Constellations Changing Positions!!!!       :D  <----(smiley face)

Explanation:

Due to the earth's rotation, stars appear to move. As the Earth rotates from west to east, the stars appear to rise in the East, moving across south to set in the west. The Sun will appear to move through the stars, making one complete circuit of the sky in 365 days!!

(yes i'm literally 9+6 years old and idek why i'm doing this XD )

3 0
2 years ago
Read 2 more answers
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