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laiz [17]
3 years ago
15

Which of the following are considered pure substances?

Chemistry
1 answer:
Helen [10]3 years ago
8 0
B.Elements

Explanation: they cannot be separated
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What are the similarities between DIFFUSION, FACILITATED DIFFUSION and OSMOSIS?
nalin [4]
Osmosis and diffusion are related processes that display similarities. Both osmosis and diffusion equalize the concentration of two solutions. Both diffusion and osmosis are passive transport processes, which means they do not require any input of extra energy to occur. In both diffusion and osmosis, particles move from an area of higher concentration to one of lower concentration. Osmosis and facilitated diffusion both account for movement of molecules from a region of high concentration to a region of low concentration.
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2 years ago
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Of the following elements ____ can form a rare +4 ion *
swat32

Answer:

d is the answer.........

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3 years ago
A useful single-displacement reaction involves thermite, which is a
Licemer1 [7]
The reaction of iron (III) oxide and aluminum is initiated by heat released from a small amount "starter mixture". This reaction is an oxidation-reduction reaction, a single replacement reaction, producing great quantities of heat (flame and sparks) and a stream of molten iron and aluminum oxide which pours out of a hole in the bottom of the pot into sand.

The balanced chemical equation for this reaction is:

2 Al(s) + Fe2O3(s) --> 2Fe(s) + Al2O3(s) + 850 kJ/mol

Curriculum Notes
This chemical reaction can be used to demonstrate an exothermic reaction, a single replacement or oxidation-reduction reaction, and the connection between ∆H calculated for this reaction using heats of formation and Hess' Law and calculating ∆H for this reaction using qrxn = mc∆T and the moles of limiting reactant. This reaction also illustrates the role of activation energy in a chemical reaction. The thermite mixture must be raised to a high temperature before it will react.

To determine how much thermal energy is released in this reaction, heats of formation values and Hess' Law can be used.

By definition, the deltaHfo of an element in its standard state is zero.

2 Al(s) + Fe2O3(s) --> 2Fe (s) + Al2O3 (s)

The deltaH for this reaction is the sum of the deltaHfo's of the products - the sum of the deltaHfo's of the reactants (multiplying each by their stoichiometric coefficient in the balanced reaction equation), i.e.:

deltaHorxn = (1 mol)(deltaHfoAl2O3) + (2 mol)(deltaHfoFe) - (1 mol)(deltaHfoFe2O3) - (2 mol)(deltaHfoAl)

deltaHorxn = (1 mol)(-1,669.8 kJ/mol) + (2 mol)(0) - (1 mol)(-822.2 kJ/mol) - (2mol)(0 kJ/mol)

deltaHorxn = -847.6 kJ

The melting point of iron is 1530°C (or 2790°F).
MARK ME BRAINLIEST

7 0
2 years ago
Calculate the mass percent composition of sulfur in Al2(SO4)3.
Anastaziya [24]
The molar mass of aluminum sulftae is 342.14 g/mol.

Since the subscript shows that there are 3 sulfurs within the substance, the total mass of sulfur is 96.21g/mol

Now take the mass of the sulfur and divide it by the molar mass of aluminum sulfate, then multiply by 100:
(96.21/342.15)(100) = 28.1% mass composition of sulfate
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3 years ago
How many elements in this compound: HClO<br> 1<br> 2<br> 3<br> 4
spayn [35]
There are three elements hydrogen, chlorine, and oxygen
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