The grams of Fe₂O₃ that are formed is 47.68 g
<u><em>calculation</em></u>
Step 1: write the equation for reaction
4 Fe +3O₂ → 2 Fe₂O₃
Step 2: find the moles of Fe
moles = mass÷ molar mass
= 33.4 g÷55.8 g/mol =0.5986 moles
Step 3 : use the mole ratio to determine the moles of Fe₂O₃
That is from equation above Fe:Fe₂O₃ is 4:2 therefore the moles of Fe₂O₃ is = 0.5986 moles x 2/4 =0.2993 moles
Step 4 : find the mass of Fe₂O₃
mass = mass x molar mass
The molar mass of Fe₂O₃ = (55.8 x 2 +(15.9 x3) = 159.3 g/mol
mass is therefore = 0.2993 moles x 159.3 g/mol =47.68 g
Answer:
a - carbon is not toxic to living things
Explanation:
The reason carbon dating works is that the fresh carbon-14 gets mixed in with the rest of the carbon in the atmosphere and, since it's chemically identical to regular carbon, gets worked into whatever is presently absorbing atmospheric carbon
Answer:
20.2 kJ
Explanation:
Based on the information in the reaction, the amount of heat released per mole of Na₂O₂ (the molar enthalpy) is calculated as follows:
126 kJ / 2 mol = 63 kJ/mol Na₂O₂
The number of moles in 25.0g of Na₂O₂ must be calculated using the molecular weight of Na₂O₂ (77.978 g/mol):
(25.0 g)/(77.978 g/mol) = 0.32060 mol Na₂O₂
Thus, the heat released will be:
(63 kJ/mol)(0.32060 mol) = 20.2 kJ
Answer:
30 moles of ethanol are needed to prepare a 25 m solution, using 1200 g of water
Explanation:
This a short problem of solutions:
Our solute is ethanol: C₂H₅OH
Our solvent is water-
25 m, is our solution's concentration. m means molality (moles of solute contained in 1kg of solvent).
Our solvent mass is 1200g. We convert them to kg
1200 g . 1kg / 1000g = 1.2 kg
m = mol/kg → mol = m . kg
mol = 25 mol/kg . 1.2kg →30 moles
