Protons-19 because protons are equal to the atomic number which is 19 , electrons-19 electrons are equal to number of protons, neutrons-20 because the mass number of potassium is 39 so subtract 39 from 19 (atomic number) which gives us 20
Answer:
It depends on the number of significant figures you are changing to
Explanation:
6.02×1023=6158.46
1 sig fig = 6000
2 sig fig = 6200
3 sig fig = 6160
4 sig fig = 6158
5 sig fig = 6158.5
6 sig fig = 6158.46
When solving significant figures you have to consider the number after each number like in the case of changing to two sig fig the number following one is five and when the number is up to or greater than five you add a value of one to the number before it. But in a case where the number is less than five you just leave it like that like in the case of changing to one sig fig
Answer:
false; one could be in thin shape but thay doesnt always mean they are healthy, or fit...there is always a chance there can be malnutrition or they have a good metabolism, but to be in shape, there should be a good balance of fat and muscle in the body
Answer:
0.497 moles/L
Explanation:
The reaction that takes place is:
- C₃H₆O₃ + NaOH → C₃H₅ONa + H₂O
First we c<u>alculate the moles of lactic acid in 0,821 g</u>, using its molar mass:
- 0,821 g ÷ 90 g/mol = 9,122x10⁻³mol lactic acid
<em>One mole of lactic acid reacts with one mole of sodium hydroxide</em> (it is a monoprotic acid), so in 18,34 mL of NaOH solution there are 9,122x10⁻³moles of NaOH:
- 18.34 mL ÷ 1000 = 0,01834 L
- 9,122x10⁻³mol ÷ 0,01834 L = 0.497 moles/L
