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3 years ago

14

A given atom has 3 protons, 4 neutrons, and 3 electrons. Describe how you can use those three values to describe the structure,

charge, and mass of the atom.

1 answer:

ELEN [110]3 years ago

3 0

Charge # = protons - electons

Mass # = protons + neutrons

so that would be

3-3= charge#
3+4= mass#

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Determine the molarity of a solution with a volume of 435. mL and 0.550 mol of solute dissolved.

lora16 [44]

Answer:

M = 1.26

Explanation:

Molarity = mole of solution/liters of solution
435mL/1000 = .435L
Plugging in the numbers into the formula, we get:
Molarity = .550 mol/.435L = 1.26 M

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2 years ago

As carbon dioxide enters systemic blood, it causes more oxygen to dissociate from hemoglobin, which in turn allows more CO2 to c

vagabundo [1.1K]

Answer:

The correct answer is "False".

Explanation:

It is false that as carbon dioxide enters systemic blood, it causes more oxygen to dissociate from hemoglobin. Once an atom of oxygen binds to hemoglobin, hemoglobin change its shape and makes easier than a second and a third atom of oxygen binds towards it. This change in conformation makes no possible that carbon dioxide can cause that oxygen dissociates from hemoglobin.

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3 years ago

. Element X has a nucleon (mass) number of 19 and a proton (atomic) number of 9.

Marina86 [1]

Answer:

C

Explanation:

it belong to that group as it needs 1 electron to be chemically stable

7 0

3 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.

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3 years ago

From the choices provided below, list the reagent(s) in order that will react with 3-pentanone to form 3-pentanol

Soloha48 [4]

3-pentanone to form 3-pentanol

Here 3-pentanone reacts with H2/Pt to given 3-pentanol

So here with one step we can convert given ketone to alcohol

The reaction will be

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3 years ago