Why do different solvents affect adsorbate-surface interactions?

Substance A has the following properties.

ella [17]

It will take 1.11 min to heat the sample to its melting point.

Melting point = - 20°C

Boiling point = 85°C

∆H of fusion = 180 J/g

∆H of vap = 500 J/g

C(solid) = 1.0 J/g °C

C(liquid) = 2.5 J/g °C

C(gas) = 0.5 J/g °C

Mass of sample = 25 g

Initial temperature = - 40°C

Final temperature = 100°C

Rate of heating = 450 J/min

Specific heat capacity formula:- q = m ×C×∆T

Here, q = heat energy

m = mass

C = specific heat

∆T = temperature change

Melting point = - 20°C

C(solid) = 1.0 J/g °C

∆T = final temperature - initial temperature = -20 - (-40) = 20

Put these value in Specific heat capacity formula

q = m ×C×∆T

q = 25×1.0×20

=500J

The Rate of heating = 450 J/min

i.e. 450J = 1min

so, 500J = 1.11min

1.11 minutes does it take to heat the sample to its melting point.

The specific heat capacity is defined as the amount of heat absorbed in line with unit mass of the material whilst its temperature increases 1 °C.

Learn more about specific heat capacity here:- brainly.com/question/26866234

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3 0

1 year ago

Calculate the theoretical yield of aspirin obtained when 2.0 g of salicylic acid and 5.0 mL of acetic anhydride (density = 1.08

saw5 [17]

Answer:

The percent yield would be 73%

Explanation:

The balanced reaction for the obtention of acetylsalicylic acid (aspirin) is the following:

Salicylic acid + acetic anhydride → acetylsalicylic acid + acetic acid

C₇H₆O₃ + C₄H₆O₃ → C₉H₈O₄ + C₂H₄O₂

According to the reaction, 1 mol of salicylic acid reacts with 1 mol of acetic anhydride to give 1 mol of acetylsalicylic acid (aspirin) and 1 mol of acetic acid.

1 mol aspirin (C₉H₈O₄) = (9 x 12 g/mol) + (8 x 1 g/mol) + (4 x 16 g/mol)

= 180 g

1 mol salicylic acid (C₇H₆O₃) = (7 x 12 g/mol) + (6 x 1 g/mol) + (3 x 16 g/mol)

= 138 g

1 mol acetic anhydride (C₄H₆O₃) = (4 x 12 g/mol) + (6 x 1 g/mol) + (3 x 16 g/mol)

= 102 g

The stoichiometric ratio is = 138 g salicylic acid/102 g acetic anhydride= 1.35

We have:

2.0 g salicylic acid

acetic anhydride = 5.0 mL x 1.08 g/mL = 5.4 g

The reactants ratio is = 2.0 g salicylic acid/5.4 g acetic anhydride = 0.37

0.37 < 1.35 , therefore salicylic acid is the limiting reactant.

Now, we use the amount of salicylic acid to calculate the theoretical amount of aspirin. For this, we know that 1 mol of aspirin (180 g) is obtained from 1 mol of salycilic acid (138 g):

theoretical yield= 180 g aspirin/138 g salycilic acid x 2.0 g salycilic acid = 2.61 g aspirin

actual yield = 1.9 g

Finally, we calculate the yield:

percent yield = actual yield/theoretical yield x 100

= 1.9 g/2.6 g x 100 = 72.8% ≅ 73%

6 0

3 years ago

Hydrogen and oxygen react chemically to form water how much water would form if 14.8grams of hydrogen reacted with 34.8 grams of

pishuonlain [190]

Answer:

There will be formed 39.1935 grams H2O formed

Explanation:

Step 1: The balanced equation

2H2 + 02 → 2H20

Step 2: Given data

mass of hydrogen = 14.8 grams

Molar mass of hydrogen = 2.02 g/mole

mass of oxygen = 34.8 grams

Molar mass of oxygen = 32 g/mole

Step 3: Calculate moles

moles = mass / Molar mass

moles of hydrogen = 14.8g/ 2.02 g/mole = 7.33 moles

moles of oxygen = 34.8g / 32g/mole = 1.0875 moles

For 2 moles hydrogen consumed, we need 1 mole of oxygen.

This means oxygen is the limiting reagens and will be consumed completely. Hydrogen is the reactant in excess, there will remain 5.155 moles of hydrogen

Step 4: Calculate moles of H2O

We see that for 2 moles of H2 consumed, there is needed 1 mole of O2, to produce 2 moles of H2O.

For 1.0875 moles of oxygen consumed, there will be produced 2.175 moles of H2O

Step 5: Calculate mass of water

Mass of H2O = moles of H2O * Molar mass of H2O

Mass of H2O = 2.175 moles * 18.02 g/moles 39.1935 grams

There will be formed 39.1935 grams H2O formed

4 0

3 years ago

Which statement explains why spontaneous generation is a mistaken idea?

IceJOKER [234]

Your answer is D; Not all living things can maintain homeostasis.

8 0

3 years ago

What is the pH of a 2.5 x 10-5 M solution of HCI?

aalyn [17]

Answer:

The pH of the solution is 4.60.

Explanation:

The pH gives us an idea of the acidity or basicity of a solution. More precisely, it indicates the concentration of H30 + ions present in said solution. The pH scale ranges from 0 to 14: from 0 to 7 corresponds to acid solutions, 7 neutral solutions and between 7 and 14 basic solutions. It is calculated as:

pH = -log (H30 +)

pH= -log (2,5 x 10-5)

pH=4.60

7 0

3 years ago