All categories

2 years ago

Which of the following solutions would have [Fe3+] = 0.020 M?

Chemistry

1 answer:

Shalnov [3]2 years ago

7 0

Answer:

None of the given options

Explanation:

Let's go case by case:

A. No matter the volume, the concentration of Fe(NO₃)₃ (and thus of [Fe³⁺] as well) is 0.050 M.

B. We can calculate the moles of Fe₂(SO₄)₃:

0.020 M * 0.80 L = 0.016 mol Fe₂(SO₄)₃

Given that there are two Fe⁺³ moles per Fe₂(SO₄)₃ mol, in the solution we have 0.032 moles of Fe⁺³. With that information in mind we can calculate [Fe⁺³]:

0.032 mol Fe⁺³ / 0.80 L = 0.040 M

C. Analog to case A., the molar concentration of Fe⁺³ is 0.040 M.

D. Similar to cases A and C., [Fe⁺³] = 0.010 M.

Thus none of the given options would have [Fe⁺³] = 0.020 M.

You might be interested in

Vanadium crystallizes in a body-centered cubic lattice, and the length of the edge of a unit cell is 305 pm. What is the density

Anestetic [448]

Answer:

5.96 g/cm^3

Explanation:

Corner atom = 1/8

Atoms in center = 1

Atoms in face of the cube= 1/2

Molar mass of V = 50.94 g/mol (from period table)

1 mole = 6.02x10^23

In BCC unit cell:

(8 x 1/8)+ 1=2 per 1 unit cell

Mass: 2(50.94g)/6.02x10^23 = 1.69x10^-22 g/unit cell

305pm=(305x10^-12m÷10^-2m) x (1mL÷1cm^3)

= 2.837 x 10^-23 mL

1pm=10^-12m

1cm=10^-2m

1mL=1cm^3

density=mass/volume

density of V = 1.69x10^-22g÷2.837x10^-23mL

=5.957g/mL

=5.96g/cm^3

5 0

2 years ago

How many milliliters of 0.500 M NaOH should be added to 10.0 g of tris hydrochloride (FM 121.135) to give a pH of 7.60 in a fina

liubo4ka [24]

Answer:

41.64mL of NaOH 0.500M must be added to obtain the desire pH

Explanation:

It is possible to find pH of a buffer by using H-H equation, thus:

pH = pka + log [A⁻] / [HA]

Where [HA] is concentration of the weak acid TRIS-HCl and [A⁻] is concentration of its conjugate acid.

Replacing in H-H equation:

7.60 = 8.072 + log [A⁻] / [HA]

0.3373 = [A⁻] / [HA] (1)

10.0g of TRIS-HCl (Molar mass: 121.135g/mol) are:

10.0g ₓ (1mol / 121.135g) = 0.08255 moles of acid. That means moles of both the acid and conjugate base are:

[A⁻] + [HA] = 0.08255 (2)

Replacing (1) in (2):

0.3373 = 0.08255 - [HA] / [HA]

0.3373[HA] = 0.08255 - [HA]

1.3373[HA] = 0.08255

[HA] = 0.06173 moles

Thus:

[A⁻] = 0.08255 - 0.06173 = 0.02082 moles [A⁻]

The moles of A⁻ comes from the reaction of the weak acid with NaOH, that is:

HA + NaOH → A⁻ + H₂O + K⁺

Thus, you need to add 0.02082 moles of NaOH to produce 0.02082 moles of A⁻. As NaOH solution is 0.500M:

0.02082 moles NaOH ₓ (1L / 0.500mol) = 0.04164L of NaOH 0.500M =

<h3>41.64mL of NaOH 0.500M must be added to obtain the desire pH</h3>

3 0

2 years ago

What’s the fastest way to balance chemical equations

Anon25 [30]

Hey there!

The best way to balance chemical equations is to first start by balancing polyatomic ions such as OH and SO₄.

Next, balance other elements, but save elements that are by themselves for last, such as H₂ or Fe. Once you balance everything else you can do the ones by themselves, it's much easier.

Hope this helps!

6 0

2 years ago

Which type of volcano forms when eruptions contain mostly dush ashes and cinders?

Alisiya [41]

Stratovolcanoes, or composite volcanoes, mostly erupt dust, ash, and cinders.

6 0

2 years ago

How many moles are contained in 2.0 L of N2 at standard temperature and pressure.

GuDViN [60]

0.091 moles are contained in 2.0 L of N2 at standard temperature and pressure.

Explanation:

Data given:

volume of the nitrogen gas = 2 litres

Standard temperature = 273 K

Standard pressure = 1 atm

number of moles =?

R (gas constant) = 0.08201 L atm/mole K

Assuming nitrogen to be an ideal gas at STP, we will use Ideal Gas law

PV = nRT

rearranging the equation to calculate number of moles:

PV = nRT

n = $\frac{PV}{RT}$

putting the values in the equation:

n = $\frac{1X2}{0.08201 X 273}$

n = 0.091 moles

0.091 moles of nitrogen gas is contained in a container at STP.

6 0

2 years ago