Buffer is composed of weak acid and its conjugate base or weak base and it is conjugate acid. so The correct answer is:
0.21 M hydrofluoric acid + 0.20 M potassium Fluoride
due to the first choice contain NaOH which is strong base not weak
second choice both salts no acid or base
Third choice contain HNO₃ which is considered as strong acid
Fourth choice contain ammonia but without its conjugate acid like (NH₄Cl for example) instead it has different salt
Fifth Choice contain HF which is weak acid and KF which is its conjugate base so this is the correct one
Answer:
Volume is 1.065L
Explanation:
Hello,
We can easily solve this problem by using general gas equation.
PV / T = K
P1V1/T1 = P2V2/T2
Data;
P1 = 3.0atm
P2 = 1.0atm
T1 = 20°C = (20 + 273.15)K = 293.15K
T2 = 20°C = (20 + 273.15)K = 293.15K
V1 = 355mL = 0.355L
V2 = ?
From the data given, we can substitute it into the equation,
(P1 × V1) / T1 = (P2 × V2) / T2
(3.0 × 0.355) / 293.15 = (1.0 × V2) / 293.15
1.065 = 1.0V2
Divide both sides by 1.0
V2 = 1.065L
The volume of CO₂ released is 1.065L
Answer:
b. 11.90 Liters
Explanation:
- The balanced equation for the mentioned reaction is:
<em>3O₂ + 4Al → 2Al₂O₃,</em>
It is clear that 3.0 moles of O₂ react with 4.0 moles of Al to produce 2.0 Al₂O₃.
- Firstly, we need to calculate the no. of moles (n) of 36.12 g of Al₂O₃:
<em>n = mass/molar mass</em> = (44.18 g)/(101.96 g/mol) = <em>0.4333 mol.</em>
<u><em>using cross multiplication:</em></u>
3.0 mol of O₂ produces → 2.0 mol of Al₂O₃.
??? mol of O₂ produces → 0.4333 mol of Al₂O₃.
<em>∴ The no. of moles of O₂ needed to produce 36.12 grams of Al₂O₃</em> = (3.0 mol)(0.4333 mol)/(2.0 mol) = <em>0.65 mol.</em>
- Now, we can find the volume of O₂ used during the experiment:
We can use the general law of ideal gas: <em>PV = nRT.</em>
where, P is the pressure of the gas in atm (P = 1.3 atm).
V is the volume of the gas in L (V = ??? L).
n is the no. of moles of the gas in mol (n = 0.65 mol).
R is the general gas constant (R = 0.0821 L.atm/mol.K),
T is the temperature of the gas in K (T = 290 K).
<em>∴ V = nRT/P </em>= (0.65 mol)(0.0821 L.atm/mol.K)(290 K)/(1.3 atm) = <em>11.9 L.</em>
<em>So, the right choice is: b. 11.90 Liters.</em>
Answer:
New volume, V2 = 15mL
Explanation:
Given the following data;
Initial volume, V1 = 30mL
Initial pressure, P1 = 4atm
New pressure, P2 = 8atm
To find the new volume V2, we would use Boyles' law.
Boyles states that when the temperature of an ideal gas is kept constant, the pressure of the gas is inversely proportional to the volume occupied by the gas.
Mathematically, Boyles law is given by;
Substituting into the equation, we have;
V2 = 15mL
<em>Therefore, the new volume is 15 mL. </em>
Answer:
Volcanologists can predict eruptions if they have a thorough understanding of a volcano's eruptive history, if they can install the proper instrumentation on a volcano well in advance of an eruption, and if they can continuously monitor and adequately interpret data coming from that equipment.
Explanation: