Answer:
Explanation:
- For the balanced reaction:
<em>4Fe(s) + 3O₂(g) → 2Fe₂O₃(s).</em>
It is clear that 4 mol of Fe react with 3 mol of O₂ to produce 2 mol of Fe₂O₃.
- Firstly, we need to calculate the no. of moles of 35.8 grams of Fe metal:
no. of moles of Fe = mass/molar mass = (35.8 g)/(55.845 g/mol) = 0.64 mol.
- Now, we can find the no. of moles of O₂ is needed to react with the proposed amount of Fe:
<em><u>Using cross multiplication:</u></em>
4 mol of Fe is needed to react with → 3 mol of O₂, from stichiometry.
0.64 mol of Fe is needed to react with → ??? mol of O₂.
∴ The no. of moles of O₂ needed = (3 mol)(0.64 mol)/(4 mol) = 0.48 mol.
- Finally, we can get the volume of oxygen using the information:
<em>It is known that 1 mole of any gas occupies 22.4 L at standard P and T (STP).</em>
<em></em>
<em><u>Using cross multiplication:</u></em>
1 mol of O₂ occupies → 22.4 L, at STP conditions.
0.48 mol of O₂ occupies → ??? L.
∴ The no. of liters of O₂ = (0.48 mol)(22.4 L)/(1 mol) = 10.752 L.
Freeze drying<span> (or lyophilization) removes water from the ice cream by lowering the </span>air pressure<span> to a point where ice sublimates from a </span>solid<span> to a </span>gas<span>. The ice cream is placed in a </span>vacuum chamber<span> and frozen until the water </span>crystallizes<span>. The air pressure is lowered, creating a partial vacuum, forcing air out of the chamber; next heat is applied, </span>sublimating<span> the ice; finally a freezing coil traps the vaporized water. This process continues for hours, resulting in a freeze-dried ice cream slice. </span>
For radioactive decay, we can relate current amount, initial amount, decay constant and time using:
N = No x exp(-λt)
Half-life = ln(2)/λ
λ = ln(2) / 5730
N/No = 80% = 0.8
0.8 = exp( -ln(2)/5730 x t)
t = 1844 years
Answer:
Explanation:
Anscombe is a philosopher who has approached contemporary themes, today enormously current, precisely in the ethical and social field, stimulating the development of virtue ethics as an alternative to utilitarianism, Kantian ethics and social contract theories. Anscombe argues that what we understand as a moral obligation, what we "must" do, is an obligation to God.
Answer:
You need 8,324 g of CaCl₂ yo make this solution
Explanation:
Molarity is a way to express concentration in a solution, in units of moles of solute per liter of solution.
To know the grams of CaCl₂ it is necessary to know, first, the moles of this substance with the desired volume and concentration , thus:
0,1500 L × 
= 0,075 CaCl₂ moles
Now, with the molar mass of CaCl₂ you will obtain the necessary grams, thus:
0,075 CaCl₂ moles × 
= 8,324 g of CaCl₂
So, you need <em>8,324 g of CaCl₂</em> to make 150,0 mL of a 0,500M solution
I hope it helps!
