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4 years ago

How many moles are in 8.23*10^23 molecules of Bi? Explain your Answer clearly

Chemistry

1 answer:

stich3 [128]4 years ago

3 0

Answer:

1.367 moles of Bi

Explanation:

a mole is 6.02 X 10^23 molecules of a substance

by dividing $\frac{8.23*10^{23} }{6.02*10^{23}}$

= 8.23/6.02 = 1.367 moles of Bi

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Please show all of your work! :)

Paladinen [302]

Answer:

Explanation:

To answer this, we need to use Gay-Lussac's law, which states that:

$\frac{P_1}{T_1}= \frac{P_2}{T_2}$ , where P is pressure and T is temperature

The initial pressure we're given is 4.5 atm (so P1 = 4.5) and the temperature is 45.0°C; however, we need to change Celsius to Kelvins, so add 273 to 45.0: 45.0 + 273 = 318 K (so T1 = 318).

The final pressure is what we want to find, but we do know the final temperature is 3.1°C. Converting this to Kelvins, we get: 3.1 + 273 = 276.1 K, which means T2 = 276.1.

Plug these values in:

$\frac{P_1}{T_1}= \frac{P_2}{T_2}$

$\frac{4.5}{318}= \frac{P_2}{276.1}$

Multiply both sides by 276.1:

$P_2$ ≈ 3.9 atm

The answer is thus A.

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3 years ago

How do H3O+ and OH relate to acids, bases and the pH scale?

Liula [17]

Answer: An acid is defined with having more [H₃O+] ions, and a base is defined with having more [OH-] ions. On the pH scale, an acid has a lower pH and a base has a higher pH. With this being said, the lower the pH, the more [H₃O+] ions are present and the higher the pH, the more [OH-] ions are present.

Explanation:

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2 years ago

Ob] The electrodes of a fuel cellare in contact with water and all

iogann1982 [59]

Iron rusts when in contact with water.

8 0

4 years ago

20 N force moving a box to 30 meters distance. How much work id done? if it takes 10 sec to do this work, how much power is used

dalvyx [7]

Answer:

Work done = 600 J

Power used = 60 W

Explanation:

Given:

Force acting on the box is, $F=20\ N$

Displacement of the box is, $S=30\ m$

Time taken for the work, $t=10\ s$

Now, we know that, work is said to be done by a force only when there is displacement caused by the force in its direction.

Here, the force acting on the box causes a displacement of 30 m in its direction. So, work done is equal to the product of force and displacement caused.

Therefore, work done on the box is given as:

$Work=Force\times Displacement\\Work=F\times S\\Work=(20\ N)\times (30\ m)\\Work=600\ J$

Therefore, the work done is 600 J.

Now, we know that, power is given as work done per unit time.

So, power used is given as:

$Power=\frac{Work}{Time}\\\\Power=\frac{600\ J}{10\ s}\\\\Power=60\ W$

Therefore, the power used is 60 W.

5 0

3 years ago

How many grams of copper (II) hydroxide can be prepared from 2.4 grams of copper (II) nitrate (Cu(NO3)2 ) and excess sodium hydr

andreyandreev [35.5K]

Answer:

percentage yield = 67%

Explanation:

Mass of Cu(NO₃)₂ = 15.25 g

Mass of NaOH = 12.75 g

Percentage yield = ?

Solution:

Cu(NO₃)₂ + 2NaOH → Cu(OH)₂ + 2NaNO₃

Moles of Cu(NO₃)₂:

Number of moles = mass/ molar mass

Number of moles = 15.25 g /187.56 g/mol

Number of moles = 0.08 mol

Moles of NaOH :

Number of moles = mass/ molar mass

Number of moles = 12.75 g / 40 g/mol

Number of moles = 0.32 mol

Now we will compare the moles of Cu(OH)₂ with NaOH and Cu(NO₃)₂. NaOH : Cu(OH)₂

2 : 1

0.32 : 1/2×0.32 = 0.16 mol

Cu(NO₃)₂ : Cu(OH)₂

1 : 1

0.08 : 0.08

The number of moles produced by Cu(NO₃)₂ are less so it will limiting reactant.

Mass of Cu(OH)₂:

Mass = number of moles × molar mass

Mass = 0.08 mol × 97.6 g/mol

Mass = 7.808 g

Theoretical yield = 7.808 g

Percent yield:

percentage yield = Actual yield/ theoretical yield × 100

percentage yield = 5.23 g/ 7.808 g × 100

percentage yield = 0.67 × 100

percentage yield = 67%

5 0

3 years ago