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3 years ago

What do molecular clocks have to do with reaction rates?

1 answer:

5 0

The atomic clock is a procedure that uses the change rate of biomolecules to reason the time in ancient times when at least two living things veered. A device utilized by developmental scientists to gauge the rate of speciation utilizing changes in DNA.
Change in DNA/time = biological rate

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What is the theoretical yield of fluorenone if you oxidize 175 mg of fluorene?

My name is Ann [436]

Answer:

602 mg of CO₂ and 94.8 mg of H₂O

Explanation:

The yield is measured by the amount of each product produced by the reaction.

The chemical formula of fluorene is C₁₃H₁₀, and its molar mass is 166.223 g/mol.

The oxidation, also know as combustion, of this hydrocarbon is represented by the following balanced chemical equation:

$2C_{13}H_{10}+31O_2\rightarrow 26CO_2+10H_2O$

To calculate the yield follow these steps:

1. Mole ratio

$2molC_{13}H_{10}:31molO_2:26molCO_2:10molH_2O$

2. Convert 175mg of fluorene to number of moles

$175mg/times 1g/1,000mg=0.175g$

Number of moles = mass in grams / molar mass

$\text{number of moles}=0.175g/166.223g/mol=0.0010528mol$

3. Set a proportion for each product of the reaction

a) For CO₂

i) number of moles

$2molC_{10}H_{13}/26molCO_2=0.0010528molC_{10}H{13}/x$

$x=0.0010528molC_{10}H_{13}\times 26molCO_2/2molC_{10}H_{13}=0.013686molCO_2$

ii) mass in grams

The molar mass of CO₂ is 44.01g/mol

mass = number of moles × molar mass

mass = 0.013686 moles × 44.01 g/mol = 0.602 g = 602mg

b) For H₂O

i) number of moles

$0.0010528molC_{10}H_{13}\times10molH_2O/2molC_{10}H_{13}=0.00526molH_2O$

ii) mass in grams

The molar mass of H₂O is 18.015g/mol

mass = number of moles × molar mass

mass = 0.00526 moles × 18.015 g/mol = 0.0948mg = 94.8 mg

4 0

3 years ago

Which of the following are produced when a base is dissolved in water?

Irina-Kira [14]

Answer is: B. Hydroxide ions.

An Arrhenius base is a substance that dissociates in water to form hydroxide ions (OH⁻).

For example sodium hydroxide: NaOH(aq) → Na⁺(aq) + OH⁻(aq).

Another example, balanced chemical reaction: Ba(OH)₂(aq) → Ba²⁺(aq) + 2OH⁻(aq).

According to the Arrhenius definition barium hydroxide is base.

Acids and bases when react (neutralisation) produce salt and water.

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2 years ago

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How many km is 250 m?

Alex_Xolod [135]

There are 0.25 kilometers in 250 meters

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2 years ago

True or false? To increase the concentration of a solution, add more solute.

givi [52]

Answer:

Explanation:

Increasing the solute would increase the concentration. Increasing the solvent would decrease the concentration. For instance, if your lemonade was too tart, you would add more water to decrease the concentration. If your tea was too bitter, you could add more sugar to increase the sweetness. Changing the amounts of solute and solvent directly effect the concentration of the solution.

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3 years ago

Using two spring scales, students pull on opposite sides of a dynamic cart at rest. 5 Newtons of force is pulling left and 5 new

Blababa [14]

Answer:

Explanation:

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3 years ago

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