Answer:
That unknown substance is water
Explanation:
H2O is a compound. So it's second one.
Which of the following measurements is expressed to three significant figures?
C. 5.60 km
Hope this helps!
Answer:
0.11mole
Explanation:
Let us assume that the condition is at standard temperature and pressure(STP);
Given parameters:
Volume of water = 2.45L
Unknown:
Number of moles found in this volume of water = ?
Solution;
At STP;
Number of moles = 
Input the parameters and solve;
Number of moles of water =
= 0.11mole
The number of moles of water found is 0.11mole