The answer is the el second one since it is a physical change
True, bc each element emits lights that have an unique wavelength and frequency
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.
Mas of H = 1.8 g
Mass of S = 56.1 g
Mass of O = 42.1 g
Step 1 : convert given masses into moles.
Moles of H =
Mass of S =
Moles of O=
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For H =
For S =
For O =
Converting to whole number ratios
The ratio of H: S: O= 2: 2: 3
Hence the empirical formula is 
Metals have high density. They are always solids at room temperature.
Metalloids have intermediate density. They are generally solids at room temperature.
Non-metals have low density. They can be solids, liquids or gases at room temperature.
Based on this, the <span>class of elements that includes all of the elements that are gases at room temperature is the non-metals</span>
Answer:
0.508 L of solution.
Explanation:
Always a safe bet to convert to moles:

Where n is moles, m is mass, and MM is molar mass.
Now remember the equation for concentration (molarity):

Where C is the concentration, n is moles, and V is volume.
To make this easy, combine the two equations (note n appears in both, so you can do a substitution) and solve for V as the question asks:

Therefore we can make 0.508 L of solution.