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3 years ago

Which of these are true for a hypothesis? (You can pick more than one)

1 answer:

6 0

Hypotheisis is just like an initial building block for a building. The true statements about hypothesis among the given are-

First guess- hypothesis is a proposed explanation for something which is observed. Thus the explanation is just a guess and not a proved one.
An initial idea which is assumed to be true - The whole experiment or research is based on an assumption which is supposed to be true and the scientist works to prove that true.

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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]

Answer: The identity of the unknown acid is butanoic acid or ascorbic acid.

Explanation:

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:

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

For butanoic acid:

Mass of butanoic acid = 2.002 g

Molar mass of butanoic acid = 88 g/mol

Putting values in above equation, we get:

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

For L-tartaric acid:

Mass of L-tartaric acid = 2.002 g

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

Putting values in above equation, we get:

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

For ascorbic acid:

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

____H3PO4 + ____ KOH --> ______K3PO4 + ____H2O can someone please balance that chemical equation?

Murrr4er [49]

Answer:

H3PO4 + 3KOH ----> K3PO4 + 3H2O

Explanation:

The valency of K element is + 1 while that of PO4 compound is -3

Hence, at least 3 K atoms are needed to combine with PO4 to form K3PO4 compound.

Hence, the revised equation will be

H3PO4 + 3KOH ----> K3PO4 + 3H2O

Now, the number of atoms and charges of each element is a given equation are equal on both the left and right hand side.

6 0

3 years ago

86.14 mL of an acid solution was needed to neutralize 30.24 mL of a base solution of unknown concentrations. A second trial is r

Airida [17]

Answer:

The correct answer is option B.

Explanation:

As given ,that 30.24 mL of base was neutralize by 86.14 mL of acid which means that moles of base present in 30.24 mL are neutralized by moles of acid present in 86.14 mL.

After dilution of base from 30.24 mL to 50.0 mL .Since, the moles of base are same in the solution as that of the moles in solution before dilution. Moles of acid require to neutralize the base after dilution will same as a that of present moles of acid present in 86.14 mL.

5 0

3 years ago

PLEASE HELP ME I BEG YOU

VladimirAG [237]

The average kinetic energy of 1 mole of a gas at -32 degrees Celsius is:

3.80 x 103 J

The relationship between volume and temperature of a gas, when pressure and moles of a gas are held constant, is: V*T = k.

FALSE

The relationship between moles and volume, when pressure and temperature of a gas are held constant, is: V/n = k. We could say then, that:
If the moles of gas are tripled, the volume must also triple.

If the temperature and volume of a gas are held constant, an increase in pressure would most likely be caused by an increase in the number of moles of gas.

TRUE

If the vapor pressure of a liquid is less than the atmospheric pressure, the liquid will not boil.

TRUE

35 - AB

36 - BD

33 - true

34 - False

20 - 6

21 - orthohombic

4 0

3 years ago

16 meters per hour to miles per sec

ss7ja [257]

Answer:

2.76 (full answer) 2.7617e-6

Explanation:

6 0

3 years ago