(b) (i)

In the background information, it was stated that CaF2 has solubility, at room temperature, of 0.00160 g per 100 g of water. How

____ [38]

Answer:

2.05*10⁻⁵ moles of CF₂ can dissolve in 100 g of water.

12.82 moles of CaF₂ will dissolve in exactly 1.00 L of solution

Explanation:

First, by definition of solubility, in 100 g of water there are 0.0016 g of CaF₂. So, to know how many moles are 0.0016 g, you must know the molar mass of the compound. For that you know:

Ca: 40 g/mole
F: 19 g/mole

So the molar mass of CaF₂ is:

CaF₂= 40 g/mole + 2*19 g/mole= 78 g/mole

Now you can apply the following rule of three: if there are 78 grams of CaF₂ in 1 mole, in 0.0016 grams of the compound how many moles are there?

$moles=\frac{0.0016 grams*1 mole}{78 grams}$

moles=2.05*10⁻⁵

2.05*10⁻⁵ moles of CF₂ can dissolve in 100 g of water.

Now, to answer the following question, you can apply the following rule of three: if by definition of density in 1 mL there is 1 g of CaF₂, in 1000 mL (where 1L = 1000mL) how much mass of the compound is there?

$mass of CaF_{2}=\frac{1000 mL*1g}{1mL}$

mass of CaF₂= 1000 g

Now you can apply the following rule of three: if there are 78 grams of CaF₂ in 1 mole, in 1000 grams of the compound how many moles are there?

$moles=\frac{1000 grams*1 mole}{78 grams}$

moles=12.82

12.82 moles of CaF₂ will dissolve in exactly 1.00 L of solution

5 0

3 years ago

Which process is caused by an increase in thermal energy

Over [174]

Answer:

They're different - heat and thermal energy. ... The heat, in turn, speeds up the molecules within the pot and the water. If you place a thermometer in the water, as the water heats up, you can watch the temperature rise. Again, an increase in internal energy will result in an increase in temperature.

8 0

3 years ago

Someone please help! I will give Brainliest to who answers the best! Write an explanation of how mass determines (or affects) th

xxTIMURxx [149]

Gravity is the force of motion pulling down objects to the ground. If there was no gravity, everyone would walking as if they were on the moon.

Mass is what gravity needs. If an object has a little amount of mass, gravity will be able to easily bring it to the ground.

If an object has a very huge amount of mass, gravity will still be able to bring it to the ground but it will be hard.

For example: An airplane has a HUGE amount of mass. Gravity pulls it down but the airplane needs to be steering up in order for it to be straight. Gravity is applied on the airplane when it is landing.

BUT..... if a table is in the way of an object it depends if it will fall down to the ground or stay on the table.

If an object has little mass and a table is in the way of gravity pulling it down to the ground, the object will stay on the table. Like a plate of food on a table.

If an object has a very big amount of mass and a table is in the way of gravity pulling it to the ground, the object will break the object and make it's make to the ground. That is mostly why most of the time people have very strong tables/ anything to hold a heavy object.

Another example is if you're lifting weights and you have little amount of mass, you're most likely to get the little sized weight. It depend on you mass.

Here are some pictures I included here as well of Mass and gravity.

Glad to help! :) :D