Answer:
the correct answer is D
Explanation:
The density of gold is 19.4g/cm
54.15 g
First you start out with the equation n=cv (n= moles, c=molarity, v= volume)
You’re going to multiply 0.10M by 3.30L to get an answer of 0.33 moles of Ca(NO3)2
From there you’re gonna convert the moles to grams to get your answer, first you have to find the molar mass of Ca(NO3)2
This can be done by finding adding the molar mass of each individual substance
The answer you should get for the molar mass is 164.1 g
From there just multiply the number of moles you calculated (0.33 mol) by the molar mass (164.1 g) and your answer is going to be 54.15 g Ca(NO3)2
Answer:

Explanation:
To convert from moles to grams, we must use the molar mass.
Recall that water's molecular formula is H₂O. It contains hydrogen and oxygen. Look up the two elements masses on the Periodic Table.
- Hydrogen (H): 1.008 g/mol
- Oxygen (O): 15.999 g/mol
Now, use these masses to find water's mass. The subscript of 2 tells us there are 2 atoms of hydrogen, so we multiply hydrogen's mass by 2 and add oxygen's.
- H₂O= 2(1.008 g/mol) + 15.999 g/mol = 18.015 g/mol
Use the molar mass as a ratio.

Multiply by the given number of moles.

The moles of water will cancel.



Round to the nearest whole number. The 0 in the tenth place tells us to leave the number as is.

There are about <u>54 grams</u> of water in 3 moles.
I think it’s D, I could be wrong though
Answer:
6.33×10¯²² g
Explanation:
From the question given above, the following data were obtained:
Number of atoms = 6 atoms
Mass of copper (Cu) =?
From Avogadro's hypothesis, we understood that:
6.02×10²³ atoms = 1 mole of Cu
But 1 mole of Cu = 63.5 g
Thus,
6.02×10²³ atoms = 63.5 g of Cu
Finally, we shall determine the mass of 6 atoms of copper. This can be obtained as illustrated below:
6.02×10²³ atoms = 63.5 g of Cu
Therefore,
6 atoms = (6 × 63.5) / 6.02×10²³
6 atoms = 6.33×10¯²² g of Cu
Therefore, the mass of 6 atoms of copper is 6.33×10¯²² g.