Need help asap !!!!!!

Calculate the number of molecules in 100. g of O2 *

Sindrei [870]

I am pretty sure the answer is 6.25 molecules
See picture for explanation

6 0

3 years ago

5. A penny weighs about 2.5 g. How many moles of pennies would be required to equal the mass of the moon (7.3x10^24 kg)

schepotkina [342]

5. 1.16 x $10^{26}$ moles moles of pennies would be required to equal the mass of the moon.

6. 12.86 moles of ethanol are in a 750 ml bottle of vodka.

Explanation:

5 .Data given:

mass of penny = 2.5 grams

atomic mass of penny = 62.93 grams/mole

moles present in mass of the moon given as = 7.3 x $10^{24}$ kg

number of moles = $\frac{mass}{atomic mass of 1 mole}$

number of moles = $\frac{2.5}{62.93}$

0.039 moles of penny is present in 2.5 grams

0.039 moles of penny in 2.5 grams of it

so, x moles in 7.3 X $10^{27}$ grams

$\frac{0.039}{2.5} =\frac{x}{7.3 X 10^{27} }$

x = 1.16 x $10^{26}$ moles

so when the mass of the penny given is equal to the mass of moon, number of moles of penny present is 1.1 x $10^{26}$ .

6.

Given:

vodka = 40% ethanol

volume of vodka bottle = 750 ml

moles of ethanol =?

density of ethanol =0.79 g/ml

atomic mass of ethanol = 46.07 grams/mole

so, from the density of ethanol given we can calculate how much ethanol is present in the solution.

density = $\frac{mass}{volume}$

density x volume = mass

0.79 x 750 = 592.5 grams

number of moles = $\frac{mass}{atomic mass of 1 mole}$

number of moles of ethanol = $\frac{592.5}{46.07}$

= 12.86 moles of ethanol

6 0

3 years ago

A first-order reaction is 81omplete in 264s. A. What is the half-life for this reaction? b. How long will it take for the reacti

Arlecino [84]

A first-order reaction is 81omplete in 264s.The half-life for this reaction (i) t 1/2 = =3.465×10 −3 s.to reach 95% Completion = 285 s.

To measure reaction rates, chemists initiate the reaction, measure the concentration of the reactant or product at different times as the reaction progresses,

For a 0-order response, the mathematical expression that may be employed to determine the half of life is: t1/2 = [R]0/2k. For a first-order reaction, the half of-existence is given by: t1/2 = zero.693/ok. For a 2d-order response, the method for the half-life of the response is: 1/okay[R]0

The 1/2-life of a response (t1/2), is the quantity of time needed for a reactant concentration to lower via half of compared to its initial awareness. Its software is used in chemistry and medicine to are expecting the awareness of a substance over time

Half of the lifestyles is the time required for exactly 1/2 of the entities to decay 50%.

Learn more about first order reaction here:-

#SPJ4

5 0

1 year ago

Creating a prototype and troubleshooting o

lys-0071 [83]

D. a new technology.

6 0

3 years ago

Read 2 more answers

A person produces two sound waves with a flute, one immediately after the other. Both sound waves have the same pitch, but the s

Nitella [24]

Answer:

A) wavelength

Explanation:

6 0

3 years ago