(4) 220Fr, known as Francium-220, undergoes alpha decay, which emits an alpha particle, also known as a helium nucleus, which has a charge of +2.
Answer:
The percent composition of a component in a compound is the percent of the total mass of the compound that is due to that component. To calculate the percent composition of a component in a compound: Find the molar mass of the compound by adding up the masses of each atom.
The correct answer is C. Atoms are incredibly small and can bearly be seen with the most powerful electron microscopes. The nucleas of an atom contains protons and neutrons with electrons in orbitals around the nucleas. I hope this helps. Let me know if anything is unclear.
Answer:
275g
Explanation:
Depending on the molar mass you are given, you can use that to solve this.
(I'm going based on my science class' molar mass of sulphur being 32.07g/mol)
Starting off, the formula for finding moles is
n=m/M (moles = mass / molar mass)
We can manipulate this equation to solve for mass.
m=Mn
now fill in what we now.
m = 32.07*8.56
mass = 274.5192
Now round for significant digits (if you are needed to do)
mass = 275g
Answer:
67.8%
Explanation:
La reacción de descomposición del CaCO₃ es:
CaCO₃ → CO₂ + CaO
<em>Donde 1 mol de CaCO₃ al descomponerse produce 1 mol de CO₂ y 1 mol de CaO.</em>
Usando la ley general de los gases, las moles de dioxido de carbono son:
PV = nRT.
<em>Donde P es presión (1atm), V es volumen (20L), n son moles de gas, R es la constante de los gases (0.082atmL/molK) y T es temperatura absoluta (15 + 273.15 = 288.15K). </em>Reemplazando los valores en la ecuación:
PV / RT = n
1atmₓ20L / 0.082atmL/molKₓ288.15K = 0.846 moles
Como 1 mol de CO₂ es producido desde 1 mol de CaCO₃, las moles iniciales de CaCO₃ son 0.846moles.
La masa molar de CaCO₃ es 100.087g/mol. Así, la masa de 0.846moles de CaCO₃ es:
0.846moles ₓ (100.087g / mol) = <em>84.7g de CaCO₃</em>
Así, la pureza del marmol es:
(84.7g de CaCO₃ / 125g) ₓ 100<em> = </em>
<h3>67.8%</h3>
