Answer:
9.28
Explanation:
pOH refers to a measure of hydroxide ions concentration. pOH tells about the alkalinity of a solution. If pOH is less than 7 then aqueous solutions are alkaline, acidic if pOH is greater than 7 and neutral if pOH is equal to 7.
Concentration of the hydroxide ions = 1.9 x 10-5 M
pH = 
pOH = 14 - pH
=14 - 4.72 = 9.28
Answer:
Answers in explanation.
Explanation:
30. A (A chemical changes changes the chemical properties)
31. C (rusting is an example of a chemical change
32. B (A reaction requires energy, so some energy will be expelled)
33. B (Color change is an example of a chemical change)
34. A (The law of the conservation of mass: Mass and Energy cannot be created nor destroyed)
Answer:
the answer is d
Explanation:
It migrates to coastal areas during the winter months to catch fish.
1) Chemical equation
<span>2NH4Cl(s)+Ba(OH)2⋅8H2O(s)→2NH3(aq)+BaCl2(aq)+10H2O(l)
2) Stoichiometric ratios
2 mol NH4Cl(s) : 54.8 KJ
3) Convert 24.7 g of NH4Cl into number of moles, using the molar mass
molar mass of NH4Cl = 14 g/mol + 4*1 g/mol + 35.5 g/mol = 53.5 g/mol
number of moles = mass in grams / molar mass
number of moles = 24.7 g / 53.5 g/mol = 0.462 moles
4) Use proportions:
2 moles NH4Cl / 54.8 kJ = 0.462 moles / x
=> x = 0.462 moles * 54.8 kJ / 2 moles = 12.7 kJ
Answer: 12.7 kJ
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Answer:
ml and cm3
Explanation:
millilitres and centimetres cubed or litres and metres cubed. Any unit of measuring liquid if the substance is a a liquid or a unit cubed
