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3 years ago

Which two options are examples of waves refecting

Chemistry

1 answer:

sergey [27]3 years ago

8 0

Answer:

A voice echo

Your image in a mirror

Explanation:

hope this helps

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Convert 6.35 grams of aluminum sulfate to moles

vampirchik [111]

Answer:

There are 0.0186 moles of formula units in 6.35 grams of aluminum sulfate $\rm Al_2(SO_4)_3$ .

Explanation:

What's the empirical formula of aluminum sulfate?

Sulfate is an anion with a charge of -2 per ion. When sulfate ions are bonded to metals, the compound is likely ionic.

Aluminum is a group III metal. Its ions tend to carry a charge of +3 per ion.

The empirical formula of an ionic compound shall balance the charge on ions with as few ions as possible.

The least common multiple of 2 and 3 is 6. That is:

Three sulfate ions $\rm {SO_4}^{2-}$ will give a charge of -6.
Two aluminum ions $\rm Al^{3+}$ will give a charge of +6.

Pairing three $\rm {SO_4}^{2-}$ ions with two $\rm Al^{3+}$ will balance the charge. Hence the empirical formula: $\rm Al_2(SO_4)_3$ .

What's the mass of one mole of aluminum sulfate? In other words, what's the formula mass of $\rm Al_2(SO_4)_3$ ?

Refer to a modern periodic table for relative atomic mass data:

Al: 26.982;
S: 32.06;
O: 15.999.

There are

two Al,
three S, and
twelve O

in one formula unit of $\rm Al_2(SO_4)_3$ .

Hence the formula mass of $\rm Al_2(SO_4)_3$ :

$\underbrace{2\times 26.982}_{\rm Al} + \underbrace{3\times 32.06}_{\rm S} + \underbrace{12\times 15.999}_{\rm O} = \rm 342.132\;g\cdot mol^{-1}$ .

How many moles of formula units in 6.35 grams of $\rm Al_2(SO_4)_3$ ?

$\displaystyle n = \frac{m}{M} = \rm \frac{6.35\;g}{342.132\;g\cdot mol^{-1}} = 0.0186\;mol$ .

8 0

3 years ago

If a container holds 1mol of hydrogen, 2.5mol of helium, and 2mol of oxygen at a total pressure of 4atm, what is the partial pre

nlexa [21]

Answer:

Partial pressure O₂ = 1.78 atm

Explanation:

We can apply the mole fraction to solve the question:

Moles of gas / Total moles = Partial pressure of gas / Total pressure

Total moles = 1 H₂ + 2.5 He + 2O₂ = 4.5 moles

2 mol O₂ / 4.5 mol = Partial pressure O₂ / 4 atm

(2 mol O₂ / 4.5 mol ) . 4 atm = Partial pressure O₂ → 1.78 atm

7 0

3 years ago

Read 2 more answers

The conversion of chemical energy to mechanical energy is best described by which example? A. sunlight warming the ground B. ele

prohojiy [21]

I believe the best response would be C. Fuel being combusted to power a rocket.

4 0

4 years ago

Read 2 more answers

What information does a food web reveal that a food chain does not? A. A food web shows the actual number of joules of energy th

stira [4]

B because food web show when grass is consumed cows and horses both eat same thing with other food sources
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7 0

3 years ago

What is the mass of a 3.5 l sample of a liquid that has a density of 1.2 g/ml?

Aleks [24]

Hey there!:

Volume in mL:

3.5 * 1000 = 3500 mL

density = 1.2 g/mL

Therefore:

D = m / V

1.2 = m / 3.5

m = 1.2 * 3.5

m = 4.2 g

hope this helps!

7 0

3 years ago