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Galina-37 [17]
4 years ago
6

Explain how you would make 450 mL of a .250M NaOH solution?

Chemistry
1 answer:
Neporo4naja [7]4 years ago
4 0

Answer:

Weigh 4.5 grams of sodium hydroxide and add it to the dry volumetric flask of 450 mL followed by small amount of water to dissolve all the NaOH .After this add the water upto tye mark of 450 mL.

Explanation:

Molarity of the solution is the moles of compound in 1 Liter solutions.

Molarity=\frac{\text{Mass of compound}}{\text{Molar mas of compound}\times Volume (L)}

Mass of NaOH = x

Molar mass of NaOH = 40 g/mol

Volume of the NaOH solution =  450 mL =- 0.450 L ( 1 ml = 0.450 L)

Molarity of the solution of NaOH = 0.250 M

Molarity=\frac{1.248 g}{26 g/mol\times 0.9102254 L}=0.528 mol/L

0.250 M=\frac{x}{40 g/mol\times 0.450 L}

Solving for x:

x = 4.5 g

Weigh 4.5 grams of sodium hydroxide and add it to the dry volumetric flask of 450 mL followed by small amount of water to dissolve all the NaOH .After this add the water upto tye mark of 450 mL.

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If the sample contained 2.0 moles of KClO3 at a temperature of 214.0 °C, determine the mass of the oxygen gas produced in grams
Westkost [7]

Answer : The mass of the oxygen gas produced in grams and the pressure exerted by the gas against the container walls is, 96 grams and 1.78 atm respectively.

Explanation : Given,

Moles of KCl_3 = 2.0 moles

Molar mass of O_2 = 32 g/mole

Now we have to calculate the moles of MgO

The balanced chemical reaction is,

2KClO_3\rightarrow 2KCl+3O_2

From the balanced reaction we conclude that

As, 2 mole of KClO_3 react to give 3 mole of O_2

So, 2.0 moles of KClO_3 react to give \frac{2.0}{2}\times 3=3.0 moles of O_2

Now we have to calculate the mass of O_2

\text{ Mass of }O_2=\text{ Moles of }O_2\times \text{ Molar mass of }O_2

\text{ Mass of }O_2=(3.0moles)\times (32g/mole)=96g

Therefore, the mass of oxygen gas produced is, 96 grams.

Now we have to determine the pressure exerted by the gas against the container walls.

Using ideal gas equation:

PV=nRT\\\\PV=\frac{w}{M}RT\\\\P=\frac{w}{V}\times \frac{RT}{M}\\\\P=\rho\times \frac{RT}{M}

where,

P = pressure of oxygen gas = ?

V = volume of oxygen gas

T = temperature of oxygen gas = 214.0^oC=273+214.0=487K

R = gas constant = 0.0821 L.atm/mole.K

w = mass of oxygen gas

\rho = density of oxygen gas = 1.429 g/L

M = molar mass of oxygen gas = 32 g/mole

Now put all the given values in the ideal gas equation, we get:

P=1.429g/L\times \frac{(0.0821L.atm/mole.K)\times (487K)}{32g/mol}

P=1.78atm

Thus, the pressure exerted by the gas against the container walls is, 1.78 atm.

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Increased exercise intensity means the overall need for energy increases. As we increase exercise intensity we increase our glucose uptake and oxidation which far exceeds uptake, indicating that muscle stores of glycogen are being used. At moderate intensities (65%) there is an increased need for muscle glycogen and muscle triglycerides which is fat. At higher levels of intensities (85%) there is an even greater need for energy, and this is met almost solely by an increased uptake of glucose from the blood and from muscle glycogen.

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CH4+O2—-CO2+H2O what is the best classification for the unbalanced equations reaction and why
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A sample of aluminum weighs 100 grams and has a volume of 37.03 cm. What is the density of
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Which of the following regions does NOT match its description?
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The region that does not match its description is the fourth answer choice which is Abdominal region: spine

  • For the first answer choice - Cranial region: head

The cranial region encompasses the upper part of the head.

∴ The first answer choice matches its description.

  • For the second answer choice - Axillary region: armpits

The axillary region is an anatomical region under the shoulder joint where the arm connects to the shoulder. Therefore, it encompasses the armpits.

∴ The second answer choice matches its description.

  • For the third answer choice - Thoracic region: chest

The thoracic region runs from the base of the neck down to the abdomen. Therefore, it encompasses the chest

∴ The third answer choice matches its description

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The abdominal region is divided into four quadrants which include are

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2. Right lower quadrant fossa (RLQ)

3. Left lower quadrant fossa (LLQ)

4. Left upper quadrant fossa (LUQ)

It is also divided into nine (9) areas, all of which does not include the spine.

∴ The fourth answer choice does NOT match its description.

Hence, the region that does not match its description is the fourth answer choice which is Abdominal region: spine

Learn more here: brainly.com/question/11504303

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