Which of the following is a chemical change?I

Classify each of the following compounds as a strong acid, weak acid, strong base, or weak base, and write the Ka expression for

Katyanochek1 [597]

Answer:

See explanation below

Explanation:

There are several ways to know if an acid or base is strong. One method is calculating the pH. If the pH is really low, is a strong acid, and if it's really high is a strong base.

However we do not have a pH value here.

The other method is using bronsted - lowry theory. If an acid is strong, then his conjugate base is weak. Same thing with the bases.

Now, Looking at the 4 compounds, we can say that only two of them is weak and the other two are strong compounds. Let's see:

LiOH ---> Strong. If you try to dissociate :

LiOH ------> Li⁺ + OH⁻ The Li⁺ is a weak conjugate acid.

HF -----> Weak

HF --------> H⁺ + F⁻ The Fluorine is a relatively strong conjugate base.

HCl -----> Strong

This is actually one of the strongest acid.

NH₃ ------> Weak

Now writting the Ka and Kb expressions:

Ka = [H⁺] [F⁻] / [HF]

Kb = [NH₄⁺] [OH⁻] / [NH₃]

Finally, to calculate the [OH⁻] we need to use the following expression:

Kw = [H⁻] [OH⁻]

Solving for [OH⁻] we have:

[OH⁻] = Kw / [H⁺]

Remember that the value of Kw is 1x10⁻¹⁴. So replacing:

[OH⁻] = 1x10⁻¹⁴ / 7x10⁻⁶

[OH⁻] = 1.43x10⁻⁹ M

And now, multiplying by 10¹⁰ we have:

[OH⁻] = 1.429x10⁻⁹ * 1x10¹⁰

Hope this helps

4 0

2 years ago

How many xenon atoms are contained in 1.00 moles of xenon?

joja [24]

Answer:

6.022 x 10²³

Explanation:

The number of atoms = the number of moles x with the Avogadro's number.

(The Avogadro's number is 6.022 x 10²³ atoms / moles)

number of atoms = 1.00 moles x 6.022 x 10²³ atoms / mole

number of atoms = 6.022 x 10²³ atoms

(There is no need to simplify?) = 6.022 x 10²³

(ps. This is my first time doing this question so im sorry if i got it wrong

(つ﹏⊂)

3 0

2 years ago

Explain why world food shortages could be reduced by growing more algae.

Sonja [21]

One of the many awe-inspiring things about algae, Professor Greene explains, is that they can grow between ten and 100 times faster than land plants. In view of this speedy growth rate – combined with the fact they can thrive virtually anywhere in the right conditions – growing marine microalgae could provide a variety of solutions to some of the world’s most pressing problems.

Take, global warming. Algae sequesters CO2, as we have learned, but owing to the fact they grow faster than land plants, can cover wider areas and can be utilised in bioreactors, they can actually absorb CO2 more effectively than land plants. AI company Hypergiant Industries, for instance, say their algae bioreactor was 400 times more efficient at taking in CO2 than trees.

And it’s not just their nutritional credentials which could solve humanity’s looming food crisis, but how they are produced. Marine microalgae grow in seawater, which means they do not rely on arable land or freshwater, both of which are in limited supply. Professor Greene believes the use of these organisms could therefore release almost three million km2 of cropland for reforestation, and also conserve one fifth of global freshwater

8 0

2 years ago

The area surrounding the Pacific Ocean is often referred to as the ring of Firee due to the concentration of geologic events. De

viva [34]

Answer:

The amount of movement of tectonic plates in the area

Explanation:

The population density vary across the countries

Japan(127m), Philippines ( 103m), Indonesia (267m).

The volcanoes in Indonesia are among the most active of the pacific Ring of Fire along the north east island

5 0

3 years ago

If liquid water has a density of 1.00 g/ml at 25 °C and you allow 48 ml of water.to freeze in a 50 ml glass container, will the

tensa zangetsu [6.8K]

Can u help me :( no one is helping me

8 0

3 years ago