Here is an acid-base reaction. Hydrochloric acid (HCl) reacts with strontium hydroxide [ Sr(OH)2 ]
Ions H+ and OH- neutralize each other. If the amounts are not equal, one of them will be in excess.
Follow the steps as
1. Find moles of ions: mole= Molarity * Volume (in liter) ; n= M * V OR millimole = Molarity * Volume (in ml) ;
2. Write the equation
3. Find out excess ion
4. Use final volume (V acid + V base ) to calculate concentration of excess ion.
n HCI = 28 ml * 0.10 M = 0.28 mmol, releases 0.28 mmol H+ ions
n Sr(OH)2= 60 ml * 0.10 M= 0.60 mmol, releases 2* 0.60=1.20 mmol OH- ions
since Sr(OH)2⇒ Sr2+ + 2OH-
Neutralization reaction is OH- + H+ ---> H2O. The ratio is 1:1. That means 1 mmol hydroxide ions will neutralize 1 mmol hydrogen ions. Since OH- ions are greater in amount, they will be in excess
n(OH-) - n(H+)= 1.20 - 0.28 = 0.92 mmol OH- ions UNREACTED.
Total volume= V acid + V base= 28 ml + 60 ml = 98 ml
Molarity of OH- ions= mole / Vtotal = 0.92/98= 0.009 M
The answer is 0.009 M.
Answer:
141 mL is the volume of a 2.30 mol/L solution of Na₂CO₃ that contains 0.325 mol of solute.
Explanation:
Molarity is a measure of concentration of a solution that indicates the amount of moles of solute that appear dissolved in each liter of the mixture.
So 2.30 mol / L indicates that 2.30 moles dissolve in 1 L of solution. You want to know in what volume is contained 0.325 mol of solute. For this you apply the following rule of three: if 2.30 moles of solute are present in 1 L of solution, 0.325 moles in how much volume is it?

volume= 0.141 L
Being 1L=1000 mL, then 0.141 L=141 mL
<u><em>141 mL is the volume of a 2.30 mol/L solution of Na₂CO₃ that contains 0.325 mol of solute.</em></u>
Answer: The final temperature of nickel and water is
.
Explanation:
The given data is as follows.
Mass of water, m = 55.0 g,
Initial temp,
,
Final temp,
= ?,
Specific heat of water = 4.184
,
Now, we will calculate the heat energy as follows.
q = 
= 
Also,
mass of Ni, m = 15.0 g,
Initial temperature,
,
Final temperature,
= ?
Specific heat of nickel = 0.444 
Hence, we will calculate the heat energy as follows.
q = 
=
Therefore, heat energy lost by the alloy is equal to the heat energy gained by the water.

= -(
)
= 
Thus, we can conclude that the final temperature of nickel and water is
.
69. The student's skin was obviously warmer than the initial temperature of the bracelet. According to the second law of thermodynamics, heat transfers from a higher temperature to a lower temperature hence heat transfers from the student's skin to the bracelet warming up the bracelet.
70. moles of copper=mass of copper/molar mass of copper
=30.1g/(63.55g/mol)= 0.4736 moles Cu
71. Delta H( heat released) = mCp(deltaT) = 30.1g(0.385 J/gK)(33-19)K = 162.23J
72. Copper is chemically less active than iron.