Answer:
pH = 12.8
Explanation:
HF + NaOH → F⁻ + Na⁺ + H₂O
<em>1 mole of HF reacts with 1 mole of NaOH</em>
<em />
Initial moles of HF and NaOH are:
HF = 0.018L × (0.308mol / L) = 5.544x10⁻³mol HF
NaOH = 0.023L × (0.361mol / L) = 8.303x10⁻³mol NaOH
That means moles of NaOH remains after reaction are:
8.303x10⁻³mol - 5.544x10⁻³mol = <em>2.759x10⁻³moles NaOH</em>
Total volume is 18.0mL + 23.0mL = 41.0mL = 0.0410L
Molar concentration of NaOH is
2.759x10⁻³moles NaOH / 0.0410L = 0.0673M = [OH⁻]
pOH = - log [OH⁻] = 1.17
As pH = 14 - pOH
<em>pH = 12.8</em>
<em></em>
Balancing means there are equal amount of molecules on each side, both reactant and products. This is a method I like to do.
Under, I count how many molecules are in each side.
Cr2O3+Mg -->Cr + MgO
Cr: 2 1
O: 3 1
Mg: 1 1
Let's guess and make the number of oxygens equal on both sides.
Cr2O3+Mg -->Cr + 3MgO
Cr: 2 1
O: 3 3 EQUAL
Mg: 1 3
See what we did there? We multiplied the MgO on the products side by 3 so we can have 3 oxygens. Now let's multiply the Mg on the reactants by three so Mg AND O can be equal.
Cr2O3+3Mg -->Cr + 3 MgO
Cr: 2 1
O: 3 3 EQUAL
Mg: 3 3 EQUAL
Finally, we just need to multiply the loner Cr in the products side by two to make it equal for all elements.
Cr2O3+3Mg -->2Cr + 3 MgO
A mixture of charcoal, sand, sugar, and water is a heterogeneous mixture. Sugar can easily dissolve in water. Slightly heating the mixture will ensure all of the sugar is dissolved in the water. The mixture then can be filtered to separate out sugar solution from sand and charcoal. The mixture of sand and charcoal is washed several times with water and filtered so that no traces of sugar solution remain in the mixture. To the mixture containing sand and charcoal, water is added. Charcoal being lighter floats on the surface of water, whereas sand being heavy sinks to the bottom. The charcoal floating can be removed manually. After all the charcoal is removed, the mixture of sand and water is again filtered and the sand collected on filter paper is dried. Therefore, by using the above process sand can be separated out from a mixture of charcoal, sand, sugar, and water.
Answer:
116g/mol
Explanation:
Mg=24
NO2=46
multiple 46 by 2and then add 24
<span>The chemical formula is pretty straightforward. 2KOH reacts to produce H2O and K2O. This is the balanced chemical reaction between: Solid potassium hydroxide koh decomposing into gaseous water and solid potassium.</span>
