what is the molarity of a solution made by dissolving 21.2 g of sodium hydroxide in enough water to make 7.92 L of solution

1. Find the number of protons, neutrons, electrons and electronic structure of flourine 919F.

77julia77 [94]

1. ₉¹⁹F

2. Mg(OH)₂

3. 2H₂ + O₂ ⇒ 2H₂O

<h3>Further explanation</h3>

1. Fluorine, atomic number : 9 , mass number = 19

Symbol : ₉¹⁹F

protons=electrons=atomic number = 9

neutrons = mass number - atomic mass

$\tt n=19-9=10$

Configuration : [He] 2s² 2p⁵

2. Magnesium hydroxide is an ionic compound and is a strong base consisting of 2 ions:

Positive ion: Magnesium: Mg²⁺

negative ion: Hydroxide: OH⁻

The charges of the two are crossed, so that the compound becomes:

Mg(OH)₂

3. Reaction :

H₂ + O₂ --------> H₂O

give coefficient :

aH₂ + bO₂ --------> H₂O

H, left = 2a, right 2⇒2a=2⇒a=1

O, left = 2b, right 1⇒2b=1⇒b=0.5

Reaction becomes :

H₂ + 0.5O₂ --------> H₂O x 2

2H₂ + O₂ --------> 2H₂O

4 0

3 years ago

What is the molarity of a solution that contains 17 g of nh3 in 0.50 l of solution?

Sauron [17]

Answer:

2.0 M

Explanation:

a) M = ?

b) mass of solue = 17 g

c) solute: NH₃

d) V = 0.5o liter

<u>2) Formulae:</u>

a) number of moles, n = mass in grams / molar mass

b) M = n / V (in liters)

<u>3) Solution</u>

a) Molar mass of NH₃ = 17.03 g/mol

b) n = mass in grams / molar mass = 17 g / 17.03 g/mol = 0.998 mol NH₃

c) M = n / V (in liters) = 0.998 mol / 0.50 liter = 1.996 M

d) Round to the appropiate number of significant figures, 2: 2.0 M.

Answer: 2.0 M

8 0

3 years ago

Please help! Ionic and covalent compound.

mrs_skeptik [129]

21) Ionic
22) Ionic
23) Covalent
24) Ionic ?
25) Ionic
26) Ionic
27) Ionic ?
28) Covalent
29) Ionic ?
30) Covalent
31) Ionic ?
32) Ionic ?
33) Covalent
34) Ionic ?
35) Ionic ?
36) Covalent ?
37) Covalent
38) Ionic ?
39) Ionic ?
40) Covalent

These answers are based on if there was a nonmetal and nonmetal it’s Covalent and if there was a metal and nonmetal it was Ionic I didn’t use the electro negativity for the answers that has more than two elements, if the answers had more than two elements they have a ? Next to their answer.

I HOPE THIS HELPS AND IF IM WRONG FEEL FREE TO COMMENT AND TELL ME SO

3 0

2 years ago

An x-ray beam with wavelength 0.170 nm is directed at a crystal. As the angle of incidence increases, you observe the first stro

xeze [42]

The distance between the scattering planes in the crystal is d = 0.95 A°

<u>Explanation</u>:

The Bragg's equation is given by

2d sinθ = nλ

where,

d is the distance between the scattering planes in the crystal.

θ is the angle of diffraction.

n is the order of diffraction.

λ is the wavelength of X rays.

Given λ = 0.17 nm = 1.7 A°, angle = 62.5

2 $\times$ d $\times$ sin(62.5) = 1 $\times$ 1.7 A°

d = 0.95 A°

The distance between the scattering planes in the crystal is d = 0.95 A°

3 0

3 years ago

Hydrazine (n2h4) is used as rocket fuels. it reacts with oxygen to form nitrogen and water. write the balanced equation for this

FrozenT [24]

The answer is: volume of nitrogen is 70L.

Chemical reaction: N₂H₄ + O₂ → N₂ + 2H₂O.

m(N₂H₄) = 100 g; mass of hydrazine.

M(N₂H₄) = 32 g/mol; molar mass of hydrazine.

n(N₂H₄) = m(N₂H₄) ÷ M(N₂H₄).

n(N₂H₄) = 100 g ÷ 32 g/mol.

n(N₂H₄) = 3.125 mol; amount of hydrazine.

m(O₂) = 100 g; mass of oxygen.

M(O₂) = 32 g/mol; molar mass of oxygen.

n(O₂) = 100 g ÷ 32 g/mol.

n(O₂) = 3.125 mol; amount of oxygen.

From chemical reaction: n(O₂) : n(N₂) = 1 : 1; n(O₂) = n(N₂).

n(N₂) = 3.125 mol; amount og nitrogen gas.

V(N₂) = n(N₂) · Vm.

Vm = 22.4 L/mol; molar volume.

V(N₂) = 3.125 mol · 22.4 L/mol.

V(N₂) = 70 L.

There is not excess reagent, because hydrazine and oxygen are all used in chemical reaction.

5 0

3 years ago