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3 years ago

Which of the following is a pure substance? Choose all that apply.

Chemistry

2 answers:

worty [1.4K]3 years ago

7 0

Nickel is a pure substance

Rust is also a pure substance

Brums [2.3K]3 years ago

6 0

Nickel is a pure substance:
Final answer: B

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How many grams of water are produced when 4.50 L of

MA_775_DIABLO [31]

The answer for the following problem has been mentioned below.

Therefore the mass of the water is 5.802 grams.

Explanation:

Given:

volume of oxygen (V) = 4.50 L

Temperature (T) = 425 K

pressure of oxygen (P) = 2.50 atm

Gram molecular mass of oxygen (M) = 16.0 grams

To calculate:

mass of water (m)

We know;

According to the ideal gas equation;

P × V = n × R × T

As we know;

no of moles = $\frac{m}{M}$

m represents the mass of oxygen (m)

M represents the Gram molecular mass (M)

According to above mentioned equation;

P × V = n × R × T

P represents the pressure of the oxygen

V represents the volume of the oxygen

n represents the no of moles of the oxygen

R represents the universal gas constant

where,

the value of R is 0.0821 L atm/K moles

Substituting the values in the above equation;

2.50 × 4.50 = $\frac{m}{16.0}$ × 0.0821 × 425

11.25 = $\frac{m}{16.0}$ × 34.8925

180 = m × 34.8925

m = $\frac{180}{34.8925}$

m = 5.158 grams

Therefore the mass of the of oxygen is 5.158 grams

Now;

As we know;

$\frac{m_{1} }{M_{1} } = \frac{m_{2} }{M_{2} }$

where;

$m_{1}$ represents the mass of the oxygen

$M_{1}$ represents the gram molecular mass of the oxygen

$m_{2}$ represents the mass of the water

$M_{2}$ represents the gram molecular mass of water

From the above given formula,

$\frac{5.158}{16.0}$ = $\frac{m_{2} }{18}$

where;

Gram molecular weight of water = 18.0 u

$m_{2}$ = 5.802 grams

Therefore the mass of the water is 5.802 grams.

5 0

3 years ago

What is 1 item that is a compound? Give an example of how the 1 item is a compound :D

spayn [35]

Water

Water is a compound because it is made from more than one kind of element (oxygen and hydrogen).

3 0

3 years ago

Opal is a hydrated form of silica. If a laboratory analysis of a sample of opal reveals it to contain29.2% Si, 33.3%O, and 37.5%

ZanzabumX [31]

Let us assume that there is a 100g sample of Opal. The masses of each element will be:
29.2g Si
33.3g O
37.5g H2O
Now we divide each constituent's mass by its Mr to get the moles present
Si: (29.2 / 28) = 1.04
O: (33.3 / 16) = 2.08
H2O: (37.5 / 18) = 2.08
Now we divide by the smallest number and obtain:
Si: 1
O: 2
H2O: 2
Thus, the empirical formula of Opal is:
SiO2 . 2H2O

8 0

3 years ago

Physical changes occur when matter changes its property but not its

NNADVOKAT [17]

This statement is true

8 0

3 years ago

Difference between reactants and products.

Arisa [49]

Answer:

a reactant is a substance that is at the beginning of a Chemical reaction while a product is a substance that is present at the end of a chemical reaction.in other words a reactant is a substance used up in a chemical reaction to produce something while a reactant is what is produced after a chemical reaction.

I hope this helps

5 0

3 years ago