To change only one variable which is very important than to test the experiment to match the hypothesis again, I think. It’s been a while since I was on that lesson♀️
Answer:
Nitrogen has 7 protons and 7 electrons and 7 neutrons.
Explanation:
The atomic number of an element is the number of electrons and protons they have. The atomic mass - the atomic number of an element equals the number of nuetrons. The atomic mass of nitrogen is 14 and the atomic number is 7 therefore we have to subract, 14-7=7.
Radio waves, microwaves, infrared rays, optical rays, ultraviolet rays, X-rays, and gamma-rays.
Answer: The concentration of unknown sample is 1.8 mg/ml
Explanation:
According to the dilution law,
where,
= concentration of stock solution = ?
= volume of stock solution = 0.25 ml
= concentration of diluted solution = 0.45 mg/ml
= volume of diluted solution = (0.25+0.75) ml = 1.00 ml
Putting in the values we get:
Therefore, concentration of unknown sample is 1.8 mg/ml