Does mass<span> alone provide no information about the amount or size of a measured quantity? No, we need combine </span>mass<span> and </span>volume<span> into "one equation" to </span>determine<span> "</span>density<span>" provides more ... </span>g/mL<span>. An </span>object has<span> a mass of </span>75 grams<span> and a volume of </span>25 cc<span>. ... A </span>certain object weighs 1.25 kg<span> and </span>has<span> a </span>density of<span> </span>5.00 g/<span>mL</span>
Answer:
-125 kJ
Explanation:
You calculate the energy required to break all the bonds in the reactants. Then you subtract the energy to break all the bonds in the products.
H₂C=CH₂ + H₂ ⟶ H₃C-CH₃
Bonds: 4C-H + 1C=C 1H-H 6C-H + 1C-C
D/kJ·mol⁻¹: 413 612 436 413 347
The formula relating ΔHrxn and bond dissociation energies (D) is
ΔHrxn = Σ(Dreactants) – Σ(Dproducts)
(Note: This is an exception to the rule. All other thermochemical reactions are “products – reactants”. With bond energies, it’s “reactants – products”. The reason comes from the way we define bond energies.)
<em>For the reactant</em>s:
Σ(Dreactants) = 4 × 413 + 1 × 612 + 1 × 436 = 2700 kJ
<em>For the products:</em>
Σ(Dproducts) = 6 × 413 + 1 × 347 = 2825 kJ
<em>For the system</em>
:
ΔHrxn = 2700 - 2825 = -125 kJ
<h2>Question:</h2>
A precipitate is a solid that sometimes forms when two liquids combine.
<h2>Answer:</h2>
<u>A</u><u>.</u><u> </u><u>True</u><u> </u>
<h2>Explanation:</h2>
- <u>Because</u><u> </u><u>the</u><u> </u><u>Precipitate</u><u> </u><u>it's</u><u> </u><u>forms</u><u> </u><u>solid</u><u> </u><u>when</u><u> </u><u>two</u><u> </u><u>liquids</u><u> </u><u>combine</u><u> </u><u>to</u><u> </u><u>precipitate</u><u>.</u><u> </u>
<h2><u>#CARRYONLEARNING</u><u> </u></h2><h2><u>#STUDYWELL</u><u> </u></h2>
A, B and D should be the ones you should check
