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gladu [14]
3 years ago
11

Which is NOT a control in the following experiment?: An experiment was performed to determine how the amount of coffee grounds c

ould affect the taste of coffee. The same kind of coffee, the same coffee maker, the same amount and type of water, and the same electrical sources were used. While experimenting, the scientists notes that the more coffee grounds there were, the longer it took to brew.
Chemistry
1 answer:
Alexandra [31]3 years ago
7 0

Answer:

The same kind of coffee, the same coffee maker, the same amount and type of water, and the same electrical sources were used.

Explanation:

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A student is given a 2.002 g sample of unknown acid and is told that it might be butanoic acid, a monoprotic acid (HC4H7O2, equa
Elina [12.6K]

<u>Answer:</u> The identity of the unknown acid is butanoic acid or ascorbic acid.

<u>Explanation:</u>

To calculate the number of moles for given molarity, we use the equation:

\text{Molarity of the solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (in L)}}

Molarity of NaOH solution = 0.570 M

Volume of solution = 39.55 mL

Putting values in above equation, we get:

0.570M=\frac{\text{Moles of NaOH}\times 1000}{39.55}\\\\\text{Moles of NaOH}=\frac{0.570\times 39.55}{1000}=0.0225mol

The chemical equation for the reaction of NaOH and monoprotic acid follows:

NaOH+HX\rightarrow NaX+H_2O

By Stoichiometry of the reaction:

1 mole of NaOH reacts with 1 mole of HX

So, moles of monoprotic acid = 0.0225 moles

The chemical equation for the reaction of NaOH and diprotic acid follows:

2NaOH+H_2X\rightarrow 2NaX+2H_2O

By Stoichiometry of the reaction:

2 moles of NaOH reacts with 1 mole of diprotic acid

So, moles of diprotic acid = \frac{0.0225}{2}=0.01125moles

To calculate the number of moles, we use the equation:

\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}

  • <u>For butanoic acid:</u>

Mass of butanoic acid = 2.002 g

Molar mass of butanoic acid = 88 g/mol

Putting values in above equation, we get:

\text{Moles of butanoic acid}=\frac{2.002g}{88g/mol}=0.02275mol

  • <u>For L-tartaric acid:</u>

Mass of L-tartaric acid = 2.002 g

Molar mass of L-tartaric acid = 150 g/mol

Putting values in above equation, we get:

\text{Moles of L-tartaric acid}=\frac{2.002g}{150g/mol}=0.0133mol

  • <u>For ascorbic acid:</u>

Mass of ascorbic acid = 2.002 g

Molar mass of ascorbic acid = 176 g/mol

Putting values in above equation, we get:

\text{Moles of ascorbic acid}=\frac{2.002g}{176g/mol}=0.01137mol

As, the number of moles of butanoic acid and ascorbic acid is equal to the number of moles of acid getting neutralized.

Hence, the identity of the unknown acid is butanoic acid or ascorbic acid.

5 0
3 years ago
Sylvanite is a mineral that contains 28.0% gold by mass. How much sylvanite would you need to dig up to obtain 73.0 g of gold?
Scorpion4ik [409]

You would have to dig up 261 g of sylvanite.

Mass of sylvanite = 73.0 g Au × (100 g sylvanite/28.0 g Au) = <em>261 g</em> sylvanite.


3 0
3 years ago
The metalloid that has three valence electrons is?
bezimeni [28]
The metalloid that has three valence electrons is Boron~
8 0
3 years ago
Read 2 more answers
Which segement of the heating curve shown above represents an increase in the potential energy, but no change in the kinetic ene
Ede4ka [16]

Answer: Option (b) is the correct answer.

Explanation:

Kinetic energy is defined as the energy obtained by the molecules of an object due to their motion.

Also, it is known that kinetic energy is directly proportional to temperature.

Mathematically,       K.E = \frac{3}{2}kT

where,             T = temperature

Whereas potential energy is defined as the energy obtained by an object due to its position.

Mathematically,      P.E = mgh

where,             m = mass

                        g = acceleration due to gravity

                        h = height

Therefore, in the given curve when temperature remains constant then kinetic energy of molecules will also remain.

Hence, we can conclude that the segment QR represents an increase in the potential energy, but no change in the kinetic energy.

7 0
3 years ago
Which label belongs in the region marked X?
lubasha [3.4K]

Answer:

A) involves changes in temperature

Explanation:

The figure is missing, but I assume that the region marked X represents the region in common between Gay-Lussac's law and Charle's Law.

Gay-Lussac's law states that:

"For an ideal gas kept at constant volume, the pressure of the gas is directly proportional to its absolute temperature"

Mathematically, it can be written as

p\propto T

where p is the pressure of the gas and T its absolute temperature.

Charle's Law states that:

"For an ideal gas kept at constant pressure, the volume of the gas is directly proportional to its absolute temperature"

Mathematically, it can be written as

V\propto T

where V is the volume of the gas and T its absolute temperature.

By looking at the two descriptions of the law, we see immediately that the property that they have in common is

A) involves changes in temperature

Since the temperature is NOT kept constant in the two laws.

7 0
3 years ago
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