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2 years ago

9. Imagine that one of your kitchen workers tells you that he believes your kitchen has a pest problem and

Chemistry

1 answer:

Vesnalui [34]2 years ago

3 0

Answer:

well there are many ways to prevent a pest infestation ..... as we all know ... insects such as ants love leftovers, so store food in airtight containers like Tupperware or jars with rubber seals on the lids.

Keep a tight lid on your trash can at all times and move the trash to an outside dumpster as soon as possible.

Clean your counter tops, tables, and floors on a regular basis to prevent crumbs or food buildup

Explanation:

Hope this helps:)

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MAVERICK [17]

Answer:

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Explanation:

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2 years ago

What do you think happens to the bonds between atoms when substances melt?

Eduardwww [97]

Answer:

As a substance melts, and goes from a solid to a liquid state, the kinetic energy of the molecules increases, and the molecules move faster, and they separate further and further away from each other. The intermolecluar forces holding the molecules together become weaker. This is why a liquid can take fill the shape of its container, whereas a solid has a fixed shape.

Explanation:

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2 years ago

Which element has the following electron configuration: <br> 1s22s22p63s23p64s23d104p65s24d105p5

Natasha2012 [34]

Try adding spaces next time! That's iodine. Check all of the numbers to make sure all of the orbitals are filled, then find the ones which aren't. In this one, only the 5p5 subshell isn't full. 5p5 is the fifth row on the right side, count across the nonmetals and metalloids until the fifth one (a halogen). That's iodine, and that's your answer!

4 0

2 years ago

What volume of 0.307 m naoh must be added to 200.0ml of 0.425m acetic acid (ka = 1.75 x 10-5 ) to produce a buffer of ph = 4.250

Blababa [14]

The buffer solution target has a pH value smaller than that of pKw (i.e., pH < 7.) The solution is therefore acidic. It contains significantly more protons $\text{H}^{+}$ than hydroxide ions $\text{OH}^{-}$ . The equilibrium equation shall thus contain protons rather than a combination of water and hydroxide ions as the reacting species.

Assuming that $x \; \text{L}$ of the 0.307 $\text{mol} \cdot \text{dm}^{-3}$ sodium hydroxide solution was added to the acetic acid. Based on previous reasoning, $x$ is sufficiently small that acetic acid was in excess, and no hydroxide ion has yet been produced in the solution. The solution would thus contain $0.2000 \times 0.425 - 0.307 \; x = 0.085 - 0.307 \; x$ moles of acetic acid and $0.307 \; x$ moles of acetate ions.

Let $\text{HAc}$ denotes an acetic acid molecule and $\text{Ac}^{-}$ denotes an acetate ion. The RICE table below resembles the hydrolysis equilibrium going on within the buffer solution.

$\begin{array}{lccccc}\text{R} & \text{HAc} & \leftrightharpoons & \text{H}^{+} & + & \text{Ac}^{-}\\\text{I} & 0.085 - 0.307 \; x& & 0 & & 0.307 \; x\\\end{array}$

The buffer shall have a pH of 4.250, meaning that it shall have an equilibrium proton concentration of $10^{4.250}\; \text{mol}\cdot \text{dm}^{-3}$ . There were no proton in the buffer solution before the hydrolysis of acetic acid. Therefore the table shall have an increase of $10^{-4.250}\;\text{mol}\cdot \text{dm}^{-3}$ in proton concentration in the third row. Atoms conserve. Thus the concentration increase of protons by $10^{-4.250}\;\text{mol}\cdot \text{dm}^{-3}$ would correspond to a decrease in acetic acid concentration and an increase in acetate ion concentration by the same amount. That is:

$\begin{array}{lcccccc}\text{R} & \text{HAc} & \leftrightharpoons & \text{H}^{+} & + & \text{Ac}^{-}\\\text{I} & 0.085 - 0.307 \; x& & 0 & & 0.307 \; x\\\text{C} & - 10^{-4.250} & & +10^{-4.250} & & +10^{-4.250} \\\text{E} & 0.085 - 10^{-4.250} - 0.307 \; x& & 10^{-4.250} & & 10^{-4.250} + 0.307 \; x\end{array}$

By definition:

$\text{K}_{a} = [\text{H}^{+}] \cdot [\text{Ac}^{-}] / [\text{HAc}]\\\phantom{\text{K}_{a}} = 10^{-4.250} \times (10^{-4.250} + 0.307 \; x) / (0.085 - 10^{-4.250} - 0.307 \; x)$

The question states that

$\text{K}_{a} = 1.75 \times 10^{-5}$

such that

$10^{-4.250} \times (10^{-4.250} + 0.307 \; x) / (0.085 - 10^{-4.250} - 0.307 \; x) = 1.75 \times 10^{-5}\\6.16 \times 10^{-5} \; x = 1.48 \times 10^{-6}\\x = 0.0241$

Thus it takes $0.0241 \; \text{L}$ of sodium hydroxide to produce this buffer solution.

6 0

2 years ago

If a balloon is filled with a mixture of helium and oxygen, which gas will escape faster? Why?

Serjik [45]

Answer:

The rate of leakage will be higher for helium; its molecules move about 3 times faster than oxygen’s

Explanation:

Step 1: Data given

Molar mass helium = 4.0 g/mol

Molar mass O2 = 32 g/mol

Step 2: Graham's law

Graham's Law of Effusion states that the rate of effusion of a gas is inversely proportional to the square root of the molecular mass : 1/(Mr)^0.5

Rate of escape for He = 1/(4.0)^0.5 = 0.5

Rate of escape for O2 = 1/(32)^0.5 = 0.177

The rate of leakage will be higher for helium; its molecules move about 3 times faster than oxygen’s

4 0

3 years ago