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3 years ago

How many molecules are in 7.5 mol of h2o

1 answer:

3 0

A mole refers to 6.022⋅1023 items. H2O has 2 hydrogen atoms and 1 oxygen atom...so a total of 3 atoms in each H2O.

Therefore (6.022⋅1023)⋅ (3 atoms) =18.066⋅1023

Then we need to change the answer into proper scientific notation:
18.066⋅1023=1.8066⋅1024

Lastly, change to the proper number of significant figures. There are 4 significant figures in 6.022. Due to this we need to also have 4 significant figures in the final answer, so we would round 1.8066⋅1024→1.807⋅1024

So, your final answer is 1.807⋅1024 for one mole of h2o. multiply that by 7 and your answer is 13.55 * 1024

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Which of the following provides evidence that supports the continental drift theory? PLEASE HELP 10 POINTS

Tanya [424]

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3 years ago

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The cylinder of aluminum in class was approximately 13mm in circumference and 42mm in length. What would be it's approximate mas

Roman55 [17]

Answer:

Mass, m = 1.51 grams

Explanation:

It is given that,

The circumference of Aluminium cylinder, C = 13 mm = 1.3 cm

Length of the cylinder, h = 4.2 cm

We know that the density of the Aluminium is 2.7 g/cm³

Circumference, C = 2πr

$r=\dfrac{C}{2\pi}\\\\r=\dfrac{1.3}{2\pi}\\\\r=0.206\ cm$

Density is equal to mass per unit volume.

$d=\dfrac{m}{V}$

m is mass of the cylinder

V is the volume of the cylinder

$V=\pi r^2h\\\\V=\dfrac{22}{7}\times0.206^2\times 4.2\\\\V=0.5601\ cm^3$

So,

$m=d\times V\\\\m=2.7\times 0.5601\\\\m=1.51\ g$

So, the mass of the cylinder is 1.51 grams.

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3 years ago

A solution at ph 10 contains __________ than the same amount of solution at ph 8.

Sindrei [870]

100 times less H+

A solution at ph 10 contains 100 times less H+ than the same amount of solution at ph 8.

<h3>The pH scale: How does it function?</h3>

The pH scale determines how acidic or basic water is.
The range is 0 to 14, with 7 representing neutrality.
Acidity is indicated by pH values below 7, whereas baseness is shown by pH values above 7.
In reality, pH is a measurement of the proportion of free hydrogen and hydroxyl ions in water.

<h3>How does the pH change when two acids are combined?</h3>

An acid's strength increases with the quantity of hydrogen ions it releases.
The pH of the strong acids is between 1 and 2.
We may observe that there is no response when two acids of the same strength are combined.
It's because the end product will be neutral and the pH won't change.

<h3>How is pH value determined?</h3>

There are two ways to measure pH:

colorimetrically with indicator fluids or sheets
electrochemically with electrodes and a millivoltmeter for greater accuracy (pH meter).

To learn more about pH visit:

brainly.com/question/491373

#SPJ4

8 0

2 years ago

What is the mass, in grams, of 50.0L of N2 at STP?

vodka [1.7K]

Hey there!:

Molar mass N₂ = 28.0134 g/mol

28.0134 g ------------------- 22.4 L (at STP )

mass N₂ -------------------- 50.0 L

mass N₂ = 50.0 x 28.0134 / 22.4

mass N₂ = 1400.67 / 22.4

mass N₂ = 62.529 g

Hope this helps!

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3 years ago

What causes polar bonds

yulyashka [42]

Answer:

Bonds are polar when one element in a compound is more electronegative than the other. This creates a dipole in the molecule where one end of the molecule is partially positive and one end is partially negative

Explanation:

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3 years ago