The letters Cu, C, and Ca are all chemicals for elements<br> True or false

We expect the enthalpy of cumbustion of two isomers to be _________. The molecular formulas of two molecules are _____, so the b

Alex777 [14]

Answer:

We expect the enthalpies of combustion of two isomers to be different.

The molecular formular of the two molecules are very similar.

So the balanced chemical equation for the two combustion reactions are the same.

Explanation:

In calculation of the combustion enthalpiesfrom the isomers of the products and reactant.

The difference will be in the standard enthalpies of formation of the two combustion products.

The rod-shaped n- octane has vibrational and rotational motion possible more than the almost spherical neoprene.

4 0

3 years ago

Why is phenolphthalein not a good indicator to use for a titration that has a ph of 6.0 at the equivalence point?

vekshin1

Phenolphthalein is not a good indicator to use for a titration for a solution that has a ph of 6.0 at the equivalence point because the color change of the solution at this pH level is not sharp. It changes the color of the solution to pink starting from pH 8.3 to 10. A pH level lower than 8.3 would only show a colorless solution. Thus, you would not be able to distinguish whether the solution has reached its equivalence point at pH 6.0. It is best to use this indicator for a system that is using a strong base titrated with a weak acid.

5 0

3 years ago

a student uses universal pH paper to find the pH of three solutions . solution A has a pH of 5 solution B has a pH of 11 and sol

Andreas93 [3]

Universal pH paper turns red if it is very strongly acidic, turns orange if it is strongly acidic, turns yellow if it is weakly acidic, green if it is weakly alkali and blue if it is strongly alkali.

Solution A will turn orange as it is strongly acidic

Solution B will turn blue as it is strongly alkali

Solution C will turn yellowish green as it is neutral

5 0

3 years ago

If 21.42g of KMnO4 is actually produced what is the percent yield

mrs_skeptik [129]

Answer:

Percentage yield = 6.776%

Explanation:

Data Given:

Actual yield of KMnO₄ = 21.42g

Percentage Yield = ?

Formula Used to find Percent yield

Percentage yield = Actual yield/ theoretical yield x 100 (1)

For this Pupose First step is

We have to know the theoretical yield KMnO₄

Potasium permagnate form from MnO₄ and KOH in the presence of Oxygen by heating, in 1st step in second 2K₂MnO₄ react with HCl and give KMnO₄ .

The Reactions of formation of KMnO₄

1st Step

2MnO₄ + 4KOH + O₂ ------------> 2K₂MnO₄ + 2H₂O

2nd Step

2K₂MnO₄ + 4HCl ------------->2 KMnO₄ + H₂O + 4KCl

So form the above equation we come to know it produced 2 Mole of KMnO₄

Now we will calculate the mass of KMnO₄ by mass formulae

mass of KMnO₄ = Number of mole of KMnO₄ x Molar Mass of KMnO₄

Molar Mass of KMnO₄ = 158.034g /mol

Put value in Mass Formula

mass of KMnO₄ = 2 mol x 158.034g/mol

mass of KMnO₄ = 316.1 g

So the theoratical yield per standard reaction = 316.1 g

Now put all values in equation 1

Percentage yield = Actual yield/ theoretical yield x 100

Percentage yield = 21.42g / 316.1 g x 100

Percentage yield = 0.0678 x 100

Percentage yield = 6.776%

4 0

3 years ago

What is the number after an elements name, representing the sum of its protons and neutrons

vagabundo [1.1K]

The answer is electrons

6 0

4 years ago

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The letters Cu, C, and Ca are all chemicals for elements True or false