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2 years ago

4.2g of cerium reacted with oxygen to form 5.16g of an oxide of cerium. Find

Chemistry

1 answer:

olganol [36]2 years ago

6 0

Answer:

CeO₂

Explanation:

Hello!

In this case, since we are given the mass of both cerium and the cerium oxide, we can first compute the moles of cerium and the moles of oxygen as shown below:

$n_{Ce}=4.2gCe*\frac{1molCe}{140.12gCe}=0.03molCe\\$

$m_O=5.16g-4.2g=0.96gO\\\\n_O=0.96g*\frac{1molO}{16.0gO} =0.06molO$

Now, we simply divide each moles by 0.03 as the fewest moles in the formula to obtain the simplest formula (empirical formula) of this oxide:

$Ce=\frac{0.03}{0.03}=1\\\\O =\frac{0.06}{0.03}=2$

Thus, the formula turns out:

$CeO_2$

Regards!

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40.0L of N₂ gas are in a sealed container at STP.How many moles of N₂ are present?9 mol

Vinvika [58]

Explanation:

We have to find the number of moles of N₂ that are present in a sample that has a volume of 40.0 L at STP.

STP means Standard Conditions of Temperature and Pressure. These conditions are 273.15 K and 1 atm. We know that 1 mol of N₂ will occupy 22.4 L. We can use that ratio to find the answer to our problem.

1 mol of N₂ = 22.4 L

moles of N₂ = 40.0 L * 1 mol/(22.4 L)

moles of N₂ = 1.79 mol

Answer: 1.79 moles of nitrogen are present.

8 0

1 year ago

How many grams of aluminum are required to react with 35 mL of 2.0 M hydrochloric acid, HCl?__ HCl + __ Al --> __ AlCl3 + __

kiruha [24]

Answer:

0.6258 g

Explanation:

To determine the number grams of aluminum in the above reaction;

determine the number of moles of HCl
determine the mole ratio,
use the mole ratio to calculate the number of moles of aluminum.
use RFM of Aluminum to determine the grams required.

Moles of HCl

35 mL of 2.0 M HCl

2 moles of HCl is contained in 1000 mL

x moles of HCl is contained in 35 mL

$x \: mol \: = \: \frac{2 \: \times \: 35}{1000} \\ = 0.07 \: moles \:$

We have 0.07 moles of HCl.

Mole ratio

Balanced equation

6HCl(aq) + 2Al(s) --> 2AlCl3(aq) + 3H2(g)

Hence mole ratio = 6 : 2 (HCl : Al

but moles of HCl is 0.07, therefore the moles of Al;

$= \frac{2}{6} \times 0.07 \\ \: = 0.0233333 \: moles$

Therefore we have 0.0233333 moles of aluminum.

Grams of Aluminum

We use the formula;

$grams \: = moles \: \times \: rfm$

The RFM (Relative formula mass) of aluminum is 26.982g/mol.

Substitute values into the formula;

$= 0.0233333 \: moles \: \times \: 26.982 \: \frac{g}{mol} \\ = 0.625799 \: grams$

The number of grams of aluminum required to react with HCl is 0.6258 g.

3 0

2 years ago

What is mass per unit volume called?

harina [27]

Answer:

The correct answer is Density

Explanation:

Hope this helps you

3 0

3 years ago

Convert 0.881 mol N2 at STP to volume in liters

Vinvika [58]

The answers will be 21.5 L N2

7 0

3 years ago

Read 2 more answers

Which way would CCI2F2 orient in an electric field?

ArbitrLikvidat [17]

Answer:

See explanation

Explanation:

In looking at molecules to determine whether they are polar or not we have to look at two things basically;

i) presence of polar bonds

ii) geometry of the molecule

Now, we know that CCI2F2 is a tetrahedral molecule, but the molecule is not symmetrical. It has four polar bonds that are not all the same hence the molecule is polar.

In an electric field, polar molecules orient themselves in such a way that the positive ends of the molecule are being attracted to the negative plate while the negative ends of the molecules are attracted to the positive plate.

So the positive ends of CCI2F2 are oriented towards the negative plate of the field while the negative ends of CCI2F2 are oriented towards the positive ends of the field.

3 0

2 years ago