The electrons are electrically charged
Answer: A symmetry element is a line, a plane or a point in or through an object, about which a rotation or reflection leaves the object in an orientation indistinguishable from the original.
Answer:
66800 J
Explanation:
From the question given above, the following data were obtained:
Mass (m) = 200 g
Heat (Q) required =?
The heat required to melt the 200 g sample of water can be obtained as:
Mass (m) = 200 g
Latent heat of water (L) = 334 J/g
Heat (Q) required =?
Q = mL
Q = 200 × 334
Q = 66800 J
Thus, 66800 J of heat energy is required to melt the sample of water.
Answer:- 3.84 grams
Solution:- Volume of the sample is 44.8 mL and the density is 1.03 gram per mL.
From the density and volume we calculate the mass as:
mass = volume*density

= 46.1 g
From given info, potassium bromide solution is 8.34% potassium bromide by mass. It means if we have 100 grams of the solution then 8.34 grams of potassium bromide is present in. We need to calculate how many grams of potassium bromide are present in 46.1 grams of the solution.
The calculations could easily be done using dimensional analysis as:

= 3.84 g KBr
Hence, 3.84 grams of KBr are present in 44.8 mL of the solution.
Find the mass of the empirical formula.
You must be given a sample of some kind to calculate the weight or know how many moles are present. Then you figure out what one mol would be. The key step is multiplying the empirical formula numbers by what it takes to make 1 mol.
It would be clearer if we were working from some choices.