Significant figures communicates the level of precision in measurements.
The percent by mass sugar of a solution : 11.07%
<h3>Further explanation</h3>
Given
mass of sugar = 12.45 g
mass of water = 100 g
Required
The percent by mass
Solution
Mass of solution :

Percent mass of sugar :

Answer/Explanation:
We cannot see the passage, but SAD stands for Seasonal Affective Disorder. SAD is a type of depressive disorder related to lack of light, and therefore changes with the seasons. It is a severe version of the "winter blues"
In the winter months, where the days are shorter, individuals who suffer from SAD suffer from mood changes. They get depressed, have a reduction in energy levels, and withdraw socially. They may also gain weight. This causes problems with relationships, work, and school.
Since SAD is linked to light, SAD is likely more common in the Northern areas of the United States, where winter days are shorter.
Answer:
grams of sodium phosphate must be added to 1.4 L of this solution to completely eliminate the hard water ions
Explanation:
We will first write the balanced equation for this scenario
3 CaCl2 + 2 Na3PO4 ----> 6 NaCl + Ca3 (PO4)2
3 Mg(NO3)2 + 2 Na3PO4 -----> 6 NaNO3 + Mg3 (PO4)2
The ratio here for both calcium chloride and magnesium nitrate is 
The number of moles of each compound is equal to
Using the mole ratio of 3:2, convert each to moles of sodium phosphate.
mole of CaCl2 is equal to
Na3PO4
mole of CaCl2 is equal to
Na3PO4
Converting moles of sodium phosphate to grams of sodium phosphate we get
g/mol
grams of sodium phosphate must be added to 1.4 L of this solution to completely eliminate the hard water ions
Answer:
in disodium phosphate = 4 oxygen atoms
in phosphoric acid = 1 oxygen atom