A sample of gold has a mass of 67.2 g and a volume of 3.5 cm3. the density of gold is

Precipitation reactions always occur when two aqueous solutions are mixed (T/F)

Studentka2010 [4]

Answer: The given statement is false.

Explanation:

Precipitation reaction is defined as the chemical reaction in which two aqueous solution upon mixing together results in the formation of an insoluble solid.

For example, $NaCl(aq) + AgNO_{3} \rightarrow NaNO_{3}(aq) + AgCl(s)$

Here AgCl is present in solid state so, it is the precipitate.

But it is not necessarily true that two aqueous solutions will always result in the formation of a precipitate.

For example, $NaCl(aq) + KNO_{3}(aq) \rightarrow KCl(aq) + NaNO_{3}(aq)$

Hence, we can conclude that the statement precipitation reactions always occur when two aqueous solutions are mixed, is false.

7 0

3 years ago

Convert 5 micrometers to meters.

k0ka [10]

Answer:

5e-6

Explanation:

7 0

3 years ago

Read 2 more answers

Materials Visible Uniform Not Visible Non- Uniform State of Matter 1. Sugar and water 2. Oil and water 3. Vinegar and water 4. S

salantis [7]

Answer:

1. Uniform, non visible

2. Visible, non uniform

3. Uniform, non visible

4. Visible, non uniform

5. Visible, non uniform

Explanation:

A heterogeneous mixture is simply any mixture that is not uniform in composition — it's a non-uniform mixture of smaller constituent parts. By contrast, a mixture that is uniform in composition is a homogenous mixture

visible state of matter is when you can easily difference two components of a mixture

non visible is when the state of the matter in the substance is not visible to the eye, it can't be differentiated

4 0

3 years ago

Read 2 more answers

Consider the titration of 1L of 0.36 M NH3 (Kb=1.8x10−5) with 0.74 M HCl. What is the pH at the equivalence point of the titrati

worty [1.4K]

Answer:

C

Explanation:

The question asks to calculate the pH at equivalence point of the titration between ammonia and hydrochloric acid

Firstly, we write the equation of reaction between ammonia and hydrochloric acid.

NH3(aq)+HCl(aq)→NH4Cl(aq)

Ionically:

HCl + NH3 ---> NH4 + Cl-

Firstly, we calculate the number of moles of the ammonia as follows:

from c = n/v and thus, n = cv = 0.36 × 1 = 0.36 moles

At the equivalence point, there is equal number of moles of ammonia and HCl.

Hence, volume of HCl = number of moles/molarity of HCl = 0.36/0.74 = 0.486L

Hence, the total volume of solution will be 1 + 0.486 = 1.486L

Now, we calculate the concentration of the ammonium ions = 0.36/1.486 = 0.242M

An ICE TABLE IS USED TO FIND THE CONCENTRATION OF THE HYDROXONIUM ION(H3O+). ICE STANDS FOR INITIAL, CHANGE AND EQUILIBRIUM.

NH4+ H2O ⇄ NH3 H3O+

I 0.242 0 0

C -X +x +X

E 0.242-X X X

Since the question provides us with the base dissociation constant value K b, we can calculate the acid dissociation constant value Ka

To find this, we use the mathematical equation below

K a ⋅ K b = K w

, where K w- the self-ionization constant of water, equal to

10 ^-14 at room temperature

This means that you have

K a = K w.K b = 10 ^− 14 /1.8 * 10^-5 = 5.56 * 10^-10

Ka = [NH3][H3O+]/[NH4+]

= x * x/(0.242-x)

Since the value of Ka is small, we can say that 0.242-x ≈ 0.242

Hence, K a = x^2/0.242 = 5.56 * 10^-10

x^2 = 0.242 * 5.56 * 10^-10 = 1.35 * 10^-10

x = 0.00001161895

[H3O+] = 0.00001161895

pH = -log[H3O+]

pH = -log[0.00001161895 ] = 4.94

7 0

3 years ago

What is the treatment and disposal of Mercury<br>

PIT_PIT [208]

<h2>Hey there! :) </h2>

<h3>The treatment and disposal of Mercury:</h3>

Heating and incineration can release the mercury vapor into atmosphere causing atmospheric pollution. The process of solidification and disposal into secured landfill, gas phase recovery of mercury, and thermal treatment is gaining interest in mercury treatment and recovery field by various researchers and industries.

4 0

2 years ago