Answer:
On the periodic table, metals are separated from nonmetals by a zig-zag line stepping through carbon, phosphorus, selenium, iodine, and radon. ... Elements just to the left of the line may be termed metalloids or semimetals and have properties intermediate between those of the metals and nonmetals.
Explanation:
The answer is : 17.5 liters drained and replaced by 17.5 liters of 100% solution.
x = amount drained and replaced
(70-x) = remaining amount of 20% solution
<span>.20(70-x) + 1.00(x) = .40(70)
14 - .2x + 1x = 28
1x - .2x = 28 - 14
</span><span>.8x = 14
</span><span>x = 14/.8
x= 17,5 ( 17.5 liters drained and replaced by 17.5 liters of 100% solution)
</span>
Pb(NO₃)₂ ⇒limiting reactant
moles PbI₂ = 1.36 x 10⁻³
% yield = 87.72%
<h3>Further explanation</h3>
Given
Reaction(unbalanced)
Pb(NO₃)₂(s) + NaI(aq) → PbI₂(s) + NaNO₃(aq)
Required
- moles of PbI₂
- Limiting reactant
- % yield
Solution
Balanced equation :
Pb(NO₃)₂(s) + 2NaI(aq) → PbI₂(s) + 2NaNO₃(aq)
mol Pb(NO₃)₂ :
= 0.45 : 331 g/mol
= 1.36 x 10⁻³
mol NaI :
= 250 ml x 0.25 M
= 0.0625
Limiting reactant (mol : coefficient)
Pb(NO₃)₂ : 1.36 x 10⁻³ : 1 = 1.36 x 10⁻³
NaI : 0.0625 : 2 = 0.03125
Pb(NO₃)₂ ⇒limiting reactant(smaller ratio)
moles PbI₂ = moles Pb(NO₃)₂ = 1.36 x 10⁻³(mol ratio 1 : 1)
Mass of PbI₂ :
= mol x MW
= 1.36 x 10⁻³ x 461,01 g/mol
= 0.627 g
% yield = 0.55/0.627 x 100% = 87.72%
Answer:
moles
Explanation:
We are given:
Vapor pressure of water = 19.8 torr
Total vapor pressure = 752 torr
Vapor pressure of oxygen gas = Total vapor pressure - Vapor pressure of water = (752 - 19.8) torr = 732.2 torr
To calculate the amount of oxygen gas collected, we use the equation given by ideal gas which follows:
where,
P = pressure of the gas = 732.2 torr
The conversion of P(torr) to P(atm) is shown below:
So,
Pressure = 732.2 / 760 atm = 0.9634 atm
V = Volume of the gas = 23 mL = 0.023 L
T = Temperature of the gas = ![22^oC=[22+273]K=295K](https://tex.z-dn.net/?f=22%5EoC%3D%5B22%2B273%5DK%3D295K)
R = Gas constant = 
n = number of moles of oxygen gas = ?
Applying the equation as:
0.9634 atm × 0.023 L = n × 0.0821 L.atm/K.mol × 295.15 K
⇒n = moles
Answer:
Each colour has a purpose. Black is generally used for insulating wires. Other colours are known as 'phasing tapes'. These colours indicate the voltage level and phase of the wire.
Explanation:
