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4 years ago

The atomic mass of an element most nearly reflects the elements total number of

Chemistry

2 answers:

Harman [31]4 years ago

4 0

The answer is A I hope

klemol [59]4 years ago

3 0

Answer:

it's a

Explanation:

<h3> the atomic mass is the number of protons and neutrons in an element added together</h3>

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How much energy is evolved during the reaction of 51.2 g of al, according to the reaction below? assume that there is excess fe2

sesenic [268]

Answer : The amount of energy evolved during the reaction is, $-807.696KJ$ .

Solution : Given,

$\Delta H=-852KJ$

Mass of Al = 51.2 g

Molar mass of Al = 27 g/mole

First we have to calculate the moles of Al.

$\text{ Moles of Al}=\frac{\text{ Mass of Al}}{\text{ Molar mass of Al}}=\frac{51.2g}{27g/mole}=1.896moles$

The balanced combustion reaction is,

$Fe_2O_3+2Al\rightarrow Al_2O_3+2Fe$

From the given reaction, we conclude that

As, 2 moles of Al evolved energy = $-852KJ$

So, 1.896 moles of Al evolved energy = $\frac{-852KJ}{2moles}\times 1.896moles=-807.696KJ$

Therefore, the amount of energy evolved during the reaction is, $-807.696KJ$ .

8 0

3 years ago

Modern atomic theory states that atoms are neutral. How is this neutrality achieved?

leva [86]

Well, in an atom, there are an equal number of protons and electrons so they cancel each other out.

7 0

3 years ago

Read 2 more answers

At STP, both diamond and graphite are solids composed of carbon atoms. These solids have(1) the same crystal structure and same

maksim [4K]

The answer is (4). The crystal structure of diamond is a strong network of atoms. And structure of graphite is organized in layers. Due to the different crystal structure, they have the different properties.

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4 years ago

8. Draw the structural formula for isoprene (the building block of rubber). It should satisfy the molecular formula for isoprene

jeka57 [31]

Here are two options use the one you need :)

6 0

3 years ago

6. A 1.07 mg sample of a compound was dissolved in 78.1 mg of camphor. The resulting solution melted at 176.0 °C. What is the mo

Mice21 [21]

Answer:

The molecular mass of the compound is 156,7 g/m

Explanation:

We have to apply the freezing-point depression formula

ΔT = kf . m

where ΔT = Melting Tº of solvent pure - Melting Tº on solution

Kf is the freezing-point-depression constant

m is molality (moles of solute in 1kg of solvent)

Let's put the values on the formula

179,5º - 176º = 40 °C/m . m

3,5ºC = 40°C/m . m

3,5ºC / 40 m/ºC = m

0,0875 m

0,0875 moles of the compound in 1kg of camphor, but you don't have 1 kg, you have just 78,1 mg, so let's convert mg into kg for the rule of three.

78,1 mg / 1x10*6 = 7,81 x10*-5 kg

So if in 1kg ___ we have ____ 0,0875 moles of the compound

in 7,81 x10*-5 kg we have .... (7,81 x10*-5 kg . 0,0875 m) / 1kg

6,83x10-6 moles of compound

The moles are the mass for 1,07 mg, but for the molar mass, we should convert the mg into g so

1,07 mg / 1000 = 1,07x10*-3 g

For the molecular mass we should divide g/m so

1,07x10*-3 g / 6,83x10-6 moles = 156,7 g/m

8 0

4 years ago