Which of these is NOT a colloid?

A solution containing 3.90 g of an unknown nonelectrolyte liquid and 9.60 g water has a freezing point of −3.33 °C. The Kf = 1.8

pantera1 [17]

Answer:

The molar mass is 227 g/mol

Explanation:

Step 1: Data given

Mass of unknown nonelectrolyte = 3.90 grams

Mass of water = 9.60 grams

Freezing point of the solution = -3.33 °C

Kf = 1.86°C/m

Nonelectrolyte has a van't Hoff factor = 1

Step 2:

If you know the number of moles, and you know that is equivalent to 1.00 g, you can get molar mass.

∆T =i*m*K f

⇒ ∆T = difference in temperature between freezing point of solution and pure water = 3.33 °C

⇒ Van't hoff factor of the nonelectrolyte = 1

⇒ molality = moles nonelectrolyte / mass water

⇒ Kf = freezing point constant = 1.86 °C/m

3.33 = (1)(m)(1.86)

m = 1.79 molal = 1.79 moles / kg H2O

Step 3: Calculate moles nonelectrolyte

molality = moles / mass H2O

moles = molality * mass H2O

Moles = 1.79 molal * 0.0096

Moles = 0.017184‬ moles

Step 4: Calculate molar mass of nonelectrolyte

Molar mass = mass / moles

Molar mass = 3.90 grams / 0.017184 moles

Molar mass = 227 g/mol

The molar mass is 227 g/mol

5 0

2 years ago

What are some of the body external defenses

tekilochka [14]

<span>these include your skin, tears, mucus, cilia, stomach acid, urine flow, 'friendly' bacteria and white blood cells called neutrophils.</span>

4 0

3 years ago

Produced by the stomach to destroy bacteria

dalvyx [7]

Answer:

Your stomach lining also secretes hydrochloric acid, which creates the ideal conditions for the protein-digesting enzymes to work. The potent hydrochloric acid kills bacteria, protecting your body from harmful microbes which can enter your body in food.

4 0

3 years ago

What is the ph of a buffer prepared by adding 0.809 mol of the weak acid ha to 0.608 mol of naa in 2.00 l of solution? The disso

Anarel [89]

The pH of the buffer is 6.1236.

Explanation:

The strength of any acid solution can be obtained by determining their pH. Even the buffer solution strength of the weak acid can be determined using pH. As the dissociation constant is given, we can determine the pKa value as the negative log of dissociation constant value.

$pKa=-log[H] = - log [ 5.66 * 10^{-7}]\\ \\pka = 7 - log (5.66)=7-0.753=6.247\\\\pka = 6.247$

The pH of the buffer can be known as

$pH = pK_{a} + log[\frac{[A-]}{[HA]}}]$

The concentration of $[A^{-}] = Moles of [A]/Total volume = 0.608/2 = 0.304 M\\$

Similarly, the concentration of [HA] = $\frac{Moles of HA}{Total volume} = \frac{0.809}{2} = 0.404$

Then the pH of the buffer will be

pH = 6.247 + log [ 0.304/0.404]

$pH = 6.247 + log 0.304 - log 0.404=6.247-0.517+0.3936=6.1236$

So, the pH of the buffer is 6.1236.

5 0

3 years ago

Which type of wires (copper, aluminum, or string) are ferromagnetic metals and why?

nalin [4]

Answer: Copper isn't ferromagnetic,

Aluminum isn't ferromagnetic,

String has a ferromagnetic property

Explanation: first of all it is important to understand that all materials have diamagnetic effect.

From this we can explain two distinct property which is Paramagnetism and Ferromagnetism.

1.What do we understand by a paramagnetic material?

Ans- this describes a material that doesn't retain it's magnetic property even when the magnetic field has been removed, an example is Aluminum.

2. Ferromagnetic materials describes those type of materials that even after the removal of magnetic field retains it's magnetism. A good example of this is Iron, nickel etc.

By definition ferromagnetism is a basic property ( which depends on temperature, crystal Structure, chemical composition, etc.) That gives a material that attraction to magnet's and can form permanent magnet.

So from the examples listed in the question,

1. copper doesn't follow as a ferromagnetic material because it requires so much magnetic field to operate and is so weakly magnetized.

2. We already established aluminium as a paramagnetic material because of its weak ability to retain magnetism in the absence of magnetic field.

3. String because of its component which is (iron+carbon) has the ability to form ferrous metals.

4 0

3 years ago