The reaction equation may be written as:
2Li + 2H₂O → 2LiOH + H₂
A single mole of gas occupies 22,400 ml of gas at STP. Therefore, the moles of hydrogen gas are
75.5 / 22,400 = 0.0034 mol
According to the equation, the moles of lithium are twice that of hydrogen gas; thus,
0.0034 x 2 = 0.0068 mol
The mass of lithium is given by:
mass = moles x atomic mass
mass = 0.0068 x 6.9
mass = 0.047 grams
Answer:
(b) Calculate the molarity of a solution of 4.8 mole of HCl in 600 mL of solution. ... (g) Calculate the mass of Na2CO3 that must be used to make 700 mL of a 0.136 M Na2CO3 ... (h) What mass of NaOH is needed to make 200 mL of a 0.300 M NaOH solution? ... However, when we are reacting solutions we have to convert.
Explanation:
The right answer is D - mass.
Answer:
42 19 K→42 20 Ca+e−
Explanation:
Naturally-occurring potassium atoms have a weighted average atomic mass of 39.10 (as seen on most modern versions of the periodic table.) Each potassium atom contains 19 protons p+ and thus an average potassium atom contains about 39.10−19≈20 neutrons n0.
This particular isotope of potassium-42 contains 42 nucleons (i.e., protons and neutrons, combined;) Like other isotopes of potassium 19 out of these nucleons are protons; the rest 42−19=23 are therefore neutrons.
