Think of it this way: it is a distribution problem in which you are multiplying the 2 on the outside with each element in the parentheses. Oxygen does not have a number in front of it, so put an imaginary one in front of it to help you. Do the same with Hydrogen since it doesn't have a number in front of it either. Now you know that hydrogen has one ion and oxygen has one... but you must now multiply each of the elements' ions by two. You should now know that Oxygen has 2 ions in Calcium Hydroxide and that there are also 2 ions of Hydrogen in Calcium Hydroxide. Does this make sense?
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.
The correct answer is C.
Most of the time, double replacements produce one product that is soluble and one that is insoluble
This results in a precipitate within a liquid or aqueous solution
Hope this helps
The compound ch3ch2-sh is in the organic family know as c. thiols
Number of significant figures will be 1
Given:
weight of acetylsalicylic acid = 0. 4g
To Find:
significant figures
Solution: Significant figures are the digits of value which carry meaning towards the resolution of the measurement. They are also called significant figures in chemistry. All the experimental measurements have some kind of uncertainty associated with them.
When we convert 0.4g acetylsalicylic acid to mg we get value 400mg
when we convert 400mg to gram we get value of 0.4 gram
Since 0 before a decimal is not significant so there is only one significant figure that is 4
Learn more about Significant figure here:
brainly.com/question/24491627
#SPJ4