Answer: The empirical formula is 
Explanation:
If percentage are given then we are taking total mass is 100 grams.
So, the mass of each element is equal to the percentage given.
Mass of Br= 58.37 g
Mass of F = (100-58.37) = 41.63 g
Step 1 : convert given masses into moles.
Moles of Br=
Moles of F =
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For Br = 
For F = 
The ratio of Br: F= 1 : 3
Hence the empirical formula is 
The five strategies could include; 1) research the question of clean water availability on line and in books (2 strategies), 2) interview or ask those affected by lack of availability of clean water and find out how it affects them 3) consult with other groups ie political groups also concerned with this question and find out what they did to ensure availability to clean water and lastly to take actions to fight for the accessibility of clean water for certain groups of people like the First Nations people on reserves in Canada.
One of the defining features of an element is it's density. Calculate that and verify which substance this would be.
p=m/v
p=25g/2.38 cm^3
p=10.50 g/cm^3
Density of Silver is 10.5 g/cm^3
Hope I helped :)