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3 years ago

How many moles are in 25.0 grams of KMnO4?

Chemistry

1 answer:

ElenaW [278]3 years ago

6 0

The answer is: 0.158 mol
You find this by doing:
number of moles (n) = mass (m) / molar mass (M)
n=158.034/25.0

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Which of these is NOT true about electromagnets?

Alex17521 [72]

Answer:

Permanent = false

Explanation:

All of the other choices are true

4 0

2 years ago

An element has ccp packing with a face-centered cubic unit cell. its density is 8920 kg/m3 and the unit cell volume is 4.72 x 10

ziro4ka [17]

63.4 g/mol
First, let's determine how many atoms per unit cell in face-centered cubic. There is 8 corners, each of which has 1 atom, and each of those atoms is shared between 8 other unit cells. So 8*1/8 = 1 atom per unit cell. Additionally, there are 6 faces, each of which has 1 atom that's shared between 2 unit cells. So 6*1/2 = 3 atoms per unit cell. So each unit cell has the mass of 1+3 = 4 atoms. Since there is 1000 liters per cubic meter, the mass per liter is 8920 kg/1000 = 8.920 kg/L. Now the mass per unit cell is 8920 g * 4.72x10^-26 = 4.21024x10^-22 g per unit cell. The mass per atom is 4.21024x10^-22 g / 4 = 1.05256x10^-22 g/atom, Finally, multiply by Avogadro's number, getting 1.05256x10^-22 g/atom * 6.0221409x10^23 atom/mol = 63.38664625704 g/mol.
Rounding to 3 significant digits gives 63.4 g/mol.

5 0

4 years ago

Do all forms of radioactive decay change the identity of the original element?

hoa [83]

Explanation:

<h3>yes, Radioactive decay involves the emission of a particle and/or energy as one atom changes into another. In most instances, the atom changes its identity to become a new element.</h3>

5 0

2 years ago

Equation balancing

meriva

Answer:

For a: The balanced equation is $2S(s)+3O_2(g)\rightarrow 2SO_3(g)$

For c: The balanced equation is $2NaOH(s)+H_2SO_4(aq)\rightarrow Na_2SO_4(aq)+2H_2O(l)$

Explanation:

A balanced chemical equation is one where all the individual atoms are equal on both sides of the reaction. It follows the law of conservation of mass.

For (a):

The given unbalanced equation follows:

$S(s)+O_2(g)\rightarrow SO_3(g)$

To balance the equation, we must balance the atoms by adding 2 infront of both $S(s)$ and $SO_3$ and 3 in front of $O_2$

For the balanced chemical equation:

$2S(s)+3O_2(g)\rightarrow 2SO_3(g)$

For (b):

The given balanced equation follows:

$2Al(s)+3Cl_2(g)\rightarrow 2AlCl_3(s)$

The given equation is already balanced.

For (c):

The given unbalanced equation follows:

$2NaOH(s)+H_2SO_4(aq)\rightarrow Na_2SO_4(aq)+H_2O(l)$

To balance the equation, we must balance the atoms by adding 2 infront of $H_2O(l)$

For the balanced chemical equation:

$2NaOH(s)+H_2SO_4(aq)\rightarrow Na_2SO_4(aq)+2H_2O(l)$

For (d):

The given balanced equation follows:

$C_3H_8(g)+5O_2(g)\rightarrow 3CO_2(g)+4H_2O(g)$

The given equation is already balanced.

4 0

3 years ago

When comparing the two chair conformations for a monosubstituted cyclohexane ring, which type of substituent shows the greatest

Aleksandr [31]

Answer:

See the explanation

Explanation:

In this case, we have to keep in mind that in the monosubstituted product we only have to replace 1 hydrogen with another group. In this case, we are going to use the methyl group $CH_3$ .

In the axial position, we have a more steric hindrance because we have two hydrogens near to the $CH_3$ group. If we have more steric hindrance the molecule would be more unstable. In the equatorial positions, we don't any interactions because the $CH_3$ group is pointing out. If we don't have any steric hindrance the molecule will be more stable, that's why the molecule will the equatorial position.

See figure 1

I hope it helps!

6 0

3 years ago