19. D
20. Sorry don’t know but if I had to guess it would be B
21. A because fluorine has a higher electronegativity
22. D
23. B
24. Again don’t really know but I would guess D
25. A
Answer:
4.54 % NaOH
Explanation:
Data:
Mass of NaOH = 11.6 g
Mass of water = 38.4 g
Mass of solution = 250.0 g
Calculation:
The Rutherford–Bohr model of the hydrogen atom (Z = 1) or a hydrogen-like ion (Z > 1). In this model it is an essential feature that the photon energy (or frequency) of the electromagnetic radiation emitted (shown) when an electron jumps from one orbital to another, be proportional to the mathematical square of atomic charge (Z2). Experimental measurement by Henry Moseley of this radiation for many elements (from Z = 13 to 92) showed the results as predicted by Bohr. Both the concept of atomic number and the Bohr model were thereby given scientific credence. The atomic number is the number of _z_ an atom.
Answer:
a thing that is composed of two or more separate elements; a mixture.
Explanation: