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2 years ago

What is atom.

Chemistry

1 answer:

katovenus [111]2 years ago

3 0

Answer:

atom is the smallest indivisible particle of an element

Explanation:

The symbol of 20 element are H He li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca

element is the simplest pure form of a substance .

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Calculate the number of milliliters of 0.440 M KOH required to precipitate all of the Fe2+ ions in 187 mL of 0.692 M FeSO4 solut

EleoNora [17]

Answer:

588.2 mL

Explanation:

FeSO₄(aq) + 2KOH(aq) → Fe(OH)₂(s) + K₂SO₄(aq)

First we calculate how many Fe⁺² moles reacted, using the given concentration and volume of FeSO₄ solution (the number of FeSO₄ moles is equal to the number of Fe⁺² moles):

moles = molarity * volume

187 mL * 0.692 M = 129.404 mmol Fe⁺²

Then we convert Fe⁺² moles to KOH moles, using the stoichiometric ratios:

129.404 mmol Fe⁺² * $\frac{2mmolKOH}{1mmolFeSO_4}$ = 258.808 mmol KOH

Finally we calculate the required volume of KOH solution, using the given concentration and the calculated moles:

volume = moles / molarity

258.808 mmol KOH / 0.440 M = 588.2 mL

6 0

2 years ago

Why do foods and fuels have chemical potential energy?

Ainat [17]

Fuels are burned to produce energy, and your body breaks down the food to produce nutrients for your body.

6 0

2 years ago

Read 2 more answers

A scientist has a container with a substance inside. At first, the molecules in the substance move away from each other. Later,

ArbitrLikvidat [17]

The answers here is B) Before, the substance was a gas, later it was a liquid.

Gas particles move freely and away from each other. However, liquid particles move around each other.

Hope this helps! :)(

7 0

2 years ago

Calculate the molality of a 20.0% by mass ammonium sulfate (nh4)2so4 solution. the density of the solution is 1.117 g/ml.

olasank [31]

Hello!

We have the following data:

m1 (solute mass) = 20 % m/m
M1 (Molar mass of solute) (NH4)2 SO4 = ?
m2 (mass of the solvent) = ? (in Kg)

First we find the solute mass (m1), knowing that:

20% m/m = 20g/100mL

20 ------ 100 mL (0,1 L)
y g --------------- 1 L

y = 20/0,1
y = 200 g --> m1 = 200 g

Let's find Solute's Molar Mass, let's see:

M1 of (Nh4)2SO4
N = 2*14 = 28
H = (2*4)*1 = 8
S = 1*32 = 32
O = 4*16 = 64
----------------------
M1 of (Nh4)2SO4 = 28+8+32+64 => M1 = 132 g/mol

We must find the volume of the solvent and therefore its mass (m2), let us see:

d = 1,117 g/mL
m = 200 g
v (volumen of solute) = ?

$d = \dfrac{m}{V} \to V = \dfrac{m}{d}$

$V = \dfrac{200\:\diagup\!\!\!\!g}{1,117\:\diagup\!\!\!\!g/mL} \to V = 179\:mL\:(volumen\:of\:solute)$

The solvent volume will be:

1000 -179 => V = 821 mL (volumen of disolvent)

If: 1 mL = 1g

Then the mass of the solvent is:

m2 (mass of the solvent) = 821 g → m2 (mass of the solvent) = 0,821 Kg

Now, we apply all the data found to the formula of Molality, let us see:

$\omega = \dfrac{m_1}{M_1*m_2}$

$\omega = \dfrac{200}{132*0,821}$

$\omega = \dfrac{200}{108,372}$

$\boxed{\boxed{\omega \approx 1,8\:Molal}}\end{array}}\qquad\checkmark$

_________________________________
_________________________________

Another way to find the answer:

We have the following data:

W (molality) = ? (in molal)
n (number of mols) = ?
m1 (solute mass) = 20 % m/m = 20g/100mL → (in g to 1L) = 200 g
m2 (disolvent mass) the remaining percentage, in the case: 80 % m/m = 800 g → m2 (disolvent mass) = 0,8 Kg
M1 (Molar mass of solute) (NH4)2 SO4
N = 2*14 = 28
H = (2*4)*1 = 8
S = 1*32 = 32
O = 4*16 = 64
----------------------
M1 of (Nh4)2SO4 = 28+8+32+64 => M1 = 132 g/mol

Let's find the number of mols (n), let's see:

 $n = \dfrac{m_1}{M_1}$

$n = \dfrac{200}{132}$

$n \approx 1,5\:mol$

Now, we apply all the data found to the formula of Molality, let us see:

$\omega = \dfrac{n}{m_2}$

$\omega = \dfrac{1,5}{0,8}$

$
\boxed{\boxed{\omega \approx 1,8\:Molal}}\end{array}}\qquad\checkmark$

I hope this helps. =)

7 0

2 years ago

Alum is a compound used in a variety of applications including cosmetics, water purification, and as a food additive. It can be

vlabodo [156]

Answer:

The theoretical yield of alum is 19.873 grams and percent yield for this alum synthesis is 45.33%.

Explanation:

Mass of bottle = 10.221 g

Mass of bottle with aluminium pieces = 11.353 g

Mass of aluminium = 11.353 g - 10.221 g = 1.132 g

Mass of alum and bottle = 19.230 g

Mass of alum = 19.230 g - 10.221 g = 9.009 g