True or False<br> All cells are the same on the inside<br><br> HELP ME!

How many grams of C are there in 0.234 moles of caffeine?

elixir [45]

Solo lo ago para obtener puntos jejeje

8 0

3 years ago

10. What could the pH of a solution be if a cyanidin indicator turned blue? What is used to determine the endpoint of a titratio

Leviafan [203]

Answer:

The cyanidin indicator turns blue within a pH range of 5 - 7. The pH of the solution could be 5, 6 or 7.

An indicator is used to determine the endpoint of a titration.

Explanation:

Cyanidin indicator changes colour with each change in pH. In acidic solutions (pH < 7) cyanidin indicator will turn red, through to purple and blue, while in basic solutions (pH > 7), cyanidin indicator will change colour from aquamarine through to green and yellow. The cyanidin indicator turns blue within a pH range of 5 - 7.

Titration is a technique used in analytical chemistry to determine the unknown concentration of a solution. A solution of known concentration is added from a burette to the solution of unknown concentration until the reaction between the two solutions is complete. This known as the endpoint of the experiment. The endpoint of a titration is determined using an indicator which is added to reaction mixture. A colour charge is produced by the indicator at the endpoint of the reaction.

Note: An indicator is a dye of weak organic acids or bases which changes colour with changes in the pH of a solution. Some common indicators are methyl orange, methyl red, phenolphthalein, etc. These indicators are used to monitor the changes in the pH of solutions during a reaction.

7 0

3 years ago

The part of the electromagnetic spectrum that is necessary for the sense of sight in humans is__________

scoray [572]

Answer:

visible light

Explanation:

6 0

3 years ago

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The reaction of 2-methylbutane with chlorine would yield how many monochloro derivatives (include stereoisomers)?

zimovet [89]

The reaction of 2 methylbutane with chlorine yield 5 monochloro derivative. Methylbutane has four carbon atoms which react with chlorine. The carbon with antibonding will be chiral and it will react with chlorine. there will be four difference group around chiral carbon hence it will have stereoisomers.

7 0

3 years ago

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An object at 20∘C absorbs 25.0 J of heat. What is the change in entropy ΔS of the object? Express your answer numerically in jou

nevsk [136]

Question:

Part D) An object at 20∘C absorbs 25.0 J of heat. What is the change in entropy ΔS of the object? Express your answer numerically in joules per kelvin.

Part E) An object at 500 K dissipates 25.0 kJ of heat into the surroundings. What is the change in entropy ΔS of the object? Assume that the temperature of the object does not change appreciably in the process. Express your answer numerically in joules per kelvin.

Part F) An object at 400 K absorbs 25.0 kJ of heat from the surroundings. What is the change in entropy ΔS of the object? Assume that the temperature of the object does not change appreciably in the process. Express your answer numerically in joules per kelvin.

Part G) Two objects form a closed system. One object, which is at 400 K, absorbs 25.0 kJ of heat from the other object,which is at 500 K. What is the net change in entropy ΔSsys of the system? Assume that the temperatures of the objects do not change appreciably in the process. Express your answer numerically in joules per kelvin.

Answer:

D) 85 J/K

E) - 50 J/K

F) 62.5 J/K

G) 12.5 J/K

Explanation:

Let's make use of the entropy equation: ΔS = $\frac{Q}{T}$

Part D)

Given:

T = 20°C = 20 +273 = 293K

Q = 25.0 kJ

Entropy change will be:

ΔS = $\frac{25*1000}{293}$

= 85 J/K

Part E)

Given:

T = 500K

Q = -25.0 kJ

Entropy change will be:

ΔS = $\frac{-25*1000}{500}$

= - 50 J/K

Part F)

Given:

T = 400K

Q = 25.0 kJ

Entropy change will be:

ΔS = $\frac{25*1000}{400}$

= 62.5 J/K

Part G:

Given:

T1 = 400K

T2 = 500K

Q = 25.0 kJ

The net entropy change will be:

ΔS = $(\frac{25*1000}{400}) + (\frac{-25*1000}{500}$

= 12.5 J/K

7 0

3 years ago

True or False All cells are the same on the inside HELP ME!