Most reasonable answer:
Observations and experimentation
Answer:
A single molecule of water has been isolated for the first time by trapping it in a fullerene cage. Water molecules are never found alone — they are always hydrogen-bonded to other molecules of water or polar compounds.
While making small volumes of pure water in a lab is possible, it's not practical to “make” large volumes of water by mixing hydrogen and oxygen together. The reaction is expensive, releases lots of energy, and can cause really massive explosions.
While making small volumes of pure water in a lab is possible, it's not practical to “make” large volumes of water by mixing hydrogen and oxygen together. The reaction is expensive, releases lots of energy, and can cause really massive explosions.
A water molecule consists of three atoms; an oxygen atom and two hydrogen atoms, which are bond together like little magnets. The atoms consist of matter that has a nucleus in the centre. The difference between atoms is expressed by atomic numbers.
Explanation:
C. Ta
Tantalum is an element with an atomic number of 63 and its electronic configuration is:
[Xe] 4f¹⁴ 5d³ 6s²
Answer:
pH = 12.65
Explanation:
From the given information:
number of moles =mass in gram / molar mass
number of moles of KOH = mass of KOH / molar mass of KOH
number of moles of KOH = 0.251 g / 56.1 g/mol = 0.004474 mol
For solution :
number of moles = Concentration × volume
concetration = number of moles/ volume
concetration = 0.004474 mol / 0.100 L
concetration = 0.04474 M
We know that 1 moles KOH result into 1 mole OH⁻ ions
Therefore, Molarity of OH⁻ = 0.04474 M
Now,
pOH = -log[OH⁻]
pOH = -log (0.04474) M
pOH = 1.35
Similarly,
pH + pOH = 14
pH = 14 - pOH
pH = 14 - 1.35
pH = 12.65
<span>0.0687 m
The balanced equation is
BaCl2 + Na2SO4 ==> BaSO4 + 2 NaCl
Looking at the equation, it indicates that there's a 1 to 1 ratio of BaCl2 and Na2SO4 in the reaction. So the number of moles of each will be equal. Now calculate the number of moles of Na2SO4 we had. Start by looking up atomic weights.
Atomic weight sodium = 22.989769
Atomic weight sulfur = 32.065
Atomic weight oxygen = 15.999
Molar mass Na2SO4 = 2 * 22.989769 + 32.065 + 4 * 15.999 = 142.040538 g/mol
Moles Na2SO4 = 0.554 g / 142.040538 g/mol = 0.003900295 mol
Molarity is defined as moles per liter, so let's do the division.
0.003900295 mol / 0.0568 l = 0.068667165 mol/l = 0.068667165 m
Rounding to 3 significant figures gives 0.0687 m</span>
