Answer:
Theoretical yield: 13.9 g
Percent yield: 94 %
Explanation:
The reaction is:
CaCO₃ → CaO + CO₂
We see that the reaction is correctly balanced.
1 mol of calcium carbonate can decompose to 1 mol of calcium oxide and 1 mol of carbon dioxide.
We convert the mass to moles: 24.8 g . 1mol / 100.08g = 0.248 moles
As ratio is 1:1, 0.248 moles of salt can decompose to 1 mol of oxide.
We convert the moles to mass: 0.248 mol . 56.08g /1mol = 13.9 g
That's the theoretical yield.
To determine the percent yield we think:
(Determined yield / Theoretical yield) . 100 → (13.1 / 13.9) . 100 = 94 %
Answer:
n = 0.01302 moles
Explanation:
Pressure = 1.3 atm
Temperature = 31 °C + 273 = 304 K ( Converting to kelvin temperature)
Number of moles = ?
Volume = 250 mL = 0.250 L
These quantities are related by the equation below;
PV = nRT
n = PV / RT
n = (1.3 * 0.250) / (0.0821 * 304)
n = 0.01302 moles
Answer:
igneous rocks
Explanation:
igneous rocks forms from lava, such as obsidian, basalt, plumice, etc
There are 6.022145E+23 atom per one mole.
Answer:
A chemical change
Explanation:
The marshmallow turning brown and bubbling implies that a chemical change has taken place.
For chemical changes to occur, we observe any of the following:
- a new kind of matter is formed.
- it is always accompanied by energy changes
- the process is not easily reversible
- it involves a change in mass
- requires considerable amount of energy.
ii. Two signs that shows a chemical change has taken place is that:
- bubbles are being formed as it is roasted and it implies that new substances have been formed.
- also, significant amount of heat energy is supplied for the roasting.
