Answer:- 0.138 M
Solution:- The buffer pH is calculated using Handerson equation:
acts as a weak acid and 
as a base which is pretty conjugate base of the weak acid we have.
The acid hase two protons(hydrogen) where as the base has only one proton. So, we could write the equation as:
Phosphoric acid gives protons in three steps. So, the above equation is the second step as the acid has only two protons and the base has one proton.
So, we will use the second pKa value. The acid concentration is given as 0.10 M and we are asked to calculate the concentration of the base to make a buffer of exactly pH 7.00.
Let's plug in the values in the equation:
Taking antilog:
On cross multiply:
[base] = 1.38(0.10)
[base] = 0.138
So, the concentration of the base that is required to make the buffer is 0.138M.
Answer:
If fixed amount of gas is heated then the volume will increase because the heat will cause the molecules of gas to move freely and increase the kinetic energy.
Explanation:
If fixed amount of gas is heated then the volume will increase because the heat will cause the molecules of gas to move freely and increase the kinetic energy.
According to the Charle's law
The volume of given amount of gas is directly proportional to the temperature at constant pressure and number of moles of gas.
Mathematical expression;
V ∝ T
V = kT
V/T = k
if volume is changed from V1 to V2 and temperature change from T1 to T2 then,
V1/T1 = k V2/T2= k
V1/T1 = V2/T2
1) Calcium carbonate contains 40.0% calcium by weight.
M(CaCO₃)=100.1 g/mol
M(Ca)=40.1 g/mol
w(Ca)=40.1/100.1=0.400 (40.0%)!
2) Mass fraction of this is excessive data.
3) The solution is:
m(Ca)=1.2 g
m(CaCO₃)=M(CaCO₃)*m(Ca)/M(Ca)
m(CaCO₃)=100.1g/mol*1.2g/40.1g/mol=3.0 g
Reaction is producing more reactants than products
Answer:
D = 28.2g
Explanation:
Initial temperature of metal (T1) = 155°C
Initial Temperature of calorimeter (T2) = 18.7°C
Final temperature of solution (T3) = 26.4°C
Specific heat capacity of water (C2) = 4.184J/g°C
Specific heat capacity of metal (C1) = 0.444J/g°C
Volume of water = 50.0mL
Assuming no heat loss
Heat energy lost by metal = heat energy gain by water + calorimeter
Heat energy (Q) = MC∇T
M = mass
C = specific heat capacity
∇T = change in temperature
Mass of metal = M1
Mass of water = M2
Density = mass / volume
Mass = density * volume
Density of water = 1g/mL
Mass(M2) = 1 * 50
Mass = 50g
Heat loss by the metal = heat gain by water + calorimeter
M1C1(T1 - T3) = M2C2(T3 - T2)
M1 * 0.444 * (155 - 26.4) = 50 * 4.184 * (26.4 - 18.7)
0.444M1 * 128.6 = 209.2 * 7.7
57.0984M1 = 1610.84
M1 = 1610.84 / 57.0984
M1 = 28.21g
The mass of the metal is 28.21g
