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:
D
Explanation:
Lithium has one valence electron, so it has one to give away to have an outer shell of 8.
Sulfur has 6 valence electrons, so it needs 2 to get an outer shell of 8.
If we have two Li, that means sulfur will get 2 e- and Li will give away 2 e-, so the formula is Li₂S.
Answer:
= 1 X 10⁻⁻¹²M
Explanation:
At 25°C & 1atm [H⁺][OH⁻] = 1 x 10⁻¹⁴ => [H⁺] = 1 X 10⁻¹⁴/[OH⁻] = 1 X 10⁻¹⁴/1 X 10⁻²
= 1 X 10⁻⁻¹²M
Answer:
36.23 %
Explanation:
Let's <em>assume we have 1 mol of FeCl₂ · 4H₂O</em>. In that case we would have:
- 1 mol of FeCl₂, weighing 126.75 g (that's the molar mass of FeCl₂), and
- 4 moles of H₂O, weighing (4 * 18 g/mol) 72 g.
Now we can <u>calculate the percent by mass of water</u>:
- % mass = mass of water / total mass * 100%
- % mass =
* 100% = 36.23 %
Answer:
9kg
Explanation:
According to Newton's second law, Force=Mass x Acceleration.
Since we have the Force and the Acceleration, we can plug the values in and solve for mass using this equation:
90N = Mass x 10m/s
Divide both sides by 10:
90/10=Mass x 10/10
Mass = 9
The Mass of the object is 9kg.
Hope this helped!
