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2 years ago

Can someone help me ????

Chemistry

2 answers:

agasfer [191]2 years ago

7 0

Answer:

$\boxed {\boxed {\sf Cobalt, Iron, and \ Copper}}$

Explanation:

The Stock System states that In a chemical formula or equation, some metals need a roman numeral after their symbol. If a metal has <u>multiple oxidation states</u>, it needs a roman numeral.

Use the Periodic Table to see the oxidation states for each metal.

Cobalt (Co): +3, +2
Lithium (Li): +1
Barium (Ba): +2
Iron (Fe): +3, +2
Copper (Cu): +2, +1
Potassium (K): +1

We can see that <u>cobalt, iron, and copper</u> have more than one oxidation state, so they would require a roman numeral.

Alexandra [31]2 years ago

4 0

Answer:

B) Lithium

C) Barium

F) Potassium

Explanation:

All of the above are Inorganic Compounds.

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Caleb has a 860-kilogram car sitting in his back yard, gathering rust.

emmasim [6.3K]

<h3>Answer:</h3>

A. 860 kg

<h3>Explanation:</h3>

To answer the question we need to understand that;

Mass refers to the amount of matter in an object.
Weight, on the other hand, refers to the gravitational pull of an object to a given surface.
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Chlorine can be prepared in the laboratory by the reaction of manganese dioxide with hydrochloric acid. HCl(aq), as described by

melisa1 [442]

Answer:

0.88 g

Explanation:

Using ideal gas equation to calculate the moles of chlorine gas produced as:-

$PV=nRT$

where,

P = pressure of the gas = 805 Torr

V = Volume of the gas = 235 mL = 0.235 L

T = Temperature of the gas = $25^oC=[25+273]K=298K$

R = Gas constant = $62.3637\text{torr}mol^{-1}K^{-1}$

n = number of moles of chlorine gas = ?

Putting values in above equation, we get:

$805torr\times 0.235L=n\times 62.3637\text{ torrHg }mol^{-1}K^{-1}\times 298K\\\\n=\frac{805\times 0.235}{62.3637\times 298}=0.01017\ mol$

According to the reaction:-

$MnO_2+4HCl\rightarrow MnCl_2+2H_2O+Cl_2$

1 mole of chlorine gas is produced when 1 mole of manganese dioxide undergoes reaction.

So,

0.01017 mole of chlorine gas is produced when 0.01017 mole of manganese dioxide undergoes reaction.

Moles of $MnO_2$ = 0.01017 moles

Molar mass of $MnO_2$ = 86.93685 g/mol

So,

$Mass=Moles\times Molar\ mass$

Applying values, we get that:-

$Mass=0.01017moles \times 86.93685\ g/mol=0.88\ g$

<u>0.88 g of $MnO_2(s)$ should be added to excess HCl (aq) to obtain 235 mL of $Cl_2(g)$ at 25 degrees C and 805 Torr.</u>

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2 years ago

I’LL MAKE YOU BRAINLIEST+ FREE POINTS

Pavel [41]

Answer:

The solution's new volume is 1.68 L

Explanation:

Dilution is the procedure to prepare a less concentrated solution from a more concentrated one, and simply consists of adding more solvent. So, in a dilution the amount of solute does not vary, but the volume of the solvent varies.

In summary, a dilution is a lower concentration solution than the original.

The way to do the calculations in a dilution is through the expression:

Ci*Vi=Cf*Vf

where C and V are concentration and volume, respectively; and the i and f subscripts indicate initial and final respectively.

In this case, being:

Ci= 7 M
Vi= 0.60 L
Cf= 2.5 M
Vf=?

Replacing:

7 M*0.60 L= 2.5 M* Vf

Solving:

$Vf=\frac{7 M*0.60 L}{2.5 M}$

Vf= 1.68 L

<u><em>The solution's new volume is 1.68 L</em></u>

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2 years ago