Water is a pure substance because it is not refined like the other materials. Hope this helps!!!
The statement which best describes the law of conservation of mass is A) when a physical or a chemical change occurs, matter is not created or destroyed. The law states that matter cannot be created or destroyed by ordinary chemical or physical changes, which means that <span>the mass of all the components of a chemical reaction can be measured before and after the change in order prove that the mass is constant. So, keep in mind that </span><span>the mass of participating products is always the same as the mass of all the reactants.</span>
The molarity of a solution equals to the mole number of the solute/the volume of the solution. For NH4Br, we know that the mole mass is 98. So the molarity is (14/98) mol /0.15 L=0.95 mol/L.
Answer:
7.12 mm
Explanation:
From coulomb's law,
F = kqq'/r².................... Equation 1
Where F = force, k = proportionality constant, q and q' = The two point charges, r = distance between the two charges.
Make r the subject of the equation,
r = √(kqq'/F).......................... Equation 2
Given: q = q' = 75.0 nC = 75×10⁻⁹ C, F = 1.00 N
Constant: k = 9.0×10⁹ Nm²/C².
Substitute into equation 2
r = √[ (75×10⁻⁹ )²9.0×10⁹/1]
r = 75×10⁻⁹.√(9.0×10⁹)
r = (75×10⁻⁹)(9.49×10⁴)
r = 711.75×10⁻⁵
r = 7.12×10⁻³ m
r = 7.12 mm
Hence the distance between the point charge = 7.12 mm
Not sure about any others but I believe 3 goes with B
