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3 years ago

How would someone describe a passing grade

Chemistry

1 answer:

aliya0001 [1]3 years ago

8 0

A passing grade is a grade that makes a person eligible to go to the next grade.

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125 ml of nitrogen gas is collected at 70.0 degrees Celsius. The pressure

dybincka [34]

Answer: Volume of the gas at STP is 22.53 L.

Explanation:

Given : Volume = 125 mL (as 1 mL = 0.001 L) = 0.125 L

Temperature = $70^{o}C = (70 + 273) K = 343 K$

Pressure = $125 kPa = 125 kPa \times \frac{0.01 atm}{1 kPa} = 1.25 atm$

According to the ideal gas equation, the volume of given nitrogen gas is calculated as follows.

PV = nRT

where,

P = pressure

V = volume

n = number of moles

R = gas constant = 0.0821 L atm/mol K

T = temperature

Substitute the values into above formula as follows.

$1.25 atm \times V = 1 mol \times 0.0821 L atm/mol K \times 343 K\\V = \frac{1 mol \times 0.0821 L atm/mol K \times 343 K}{1.25 atm}\\= \frac{28.1603}{1.25} L\\= 22.53 L$

Hence, volume of the gas at STP is 22.53 L.

5 0

3 years ago

What do the individual spheres represent in the model!

Trava [24]

Answer:

the individual atom in the molecule

Explanation:

In chemistry, the ball-and-stick model is a molecular model of a chemical substance. Invidual spheres there represent atoms in the molecule. The bigger atomic number the atom has, the larger diameter of the spheres this atom has in this model.

I hope this answer will help you. Have a nice day !

5 0

3 years ago

What are the observable properties of salt and rocks, and explain how you used empirical evidence to explain that mixtures of so

777dan777 [17]

Answer:

Appearance. Pure rock salt is colorless. However, when found underground it is generally not completely pure, so may have yellow, red, gray or brown hues. It is either transparent or translucent and when you shine a light on it, its luster is vitreous, meaning it appears shiny and glassy.

Explanation:

6 0

3 years ago

If acetic acid is the only acid that vinegar contains (ka=1.8×10−5), calculate the concentration of acetic acid in the vinegar.

kicyunya [14]

Ethanoic (Acetic) acid is a weak acid and do not dissociate fully. Therefore its equilibrium state has to be considered here.

$CH_{3}COOH \ \textless \ ---\ \textgreater \ H^{+} + CH_{3}COO^{-}$

In this case pH value of the solution is necessary to calculate the concentration but it's not given here so pH = 2.88 (looked it up)

pH = 2.88 ==> $[H^{+}]$ = $10^{-2.88}$ = 0.001 $moldm^{-3}$

The change in Concentration Δ $[CH_{3}COOH]$ = 0.001 $moldm^{-3}$

  CH3COOH H+ CH3COOH
Initial   $moldm^{-3}$      $x$ 0 0

Change $moldm^{-3}$ -0.001 +0.001 +0.001

Equilibrium $moldm^{-3}$ $x$ - 0.001 0.001 0.001


Since the $k_{a}$ value is so small, the assumption
$[CH_{3}COOH]_{initial} = [CH_{3}COOH]_{equilibrium}$ can be made.

$k_{a} = [tex]= 1.8*10^{-5} = \frac{[H^{+}][CH_{3}COO^{-}]}{[CH_{3}COOH]} = \frac{0.001^{2}}{x}$

Solve for x to get the required concentration.

note: 1.)Since you need the answer in 2SF don&t round up values in the middle of the calculation like I've done here.

2.) The ICE (Initial, Change, Equilibrium) table may come in handy if you are new to problems of this kind

Hope this helps!

8 0

3 years ago

Due in minutes! Please Help Solve!

stiks02 [169]

Step by step equation

5 0

3 years ago