Answer:
19656J
Explanation:
Step 1:
Data obtained from the question.
Mass (M) = 78g
Initial temperature (T1) = 20°C
Final temperature (T2) = 80°C
Change in temperature (ΔT) = T2 – T1 =
80°C – 20°C = 60°C
Specific heat capacity (C) = 4.2J/g°C
Heat (Q) =...?
Step 2:
Determination of the heat required for the reaction.
Q = MCΔT
Q = 78 x 4.2 x 60
Q = 19656J
Therefore, 19656J of heat is required.
Answer:
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Explanation:
Electronegativity values generally increase from left to right across the periodic table. Electronegativities generally decrease from top to bottom of a group. The highest electronegativity value is for fluorine.
Nitrous acid, hno2, has an acid dissociation constant - ka of 7. 1 ✕ 10-4. what are [h3o ], [no2-], and [oh -] in 0. 40 m hno2 - 4829 M [OH^-] = 1.439 x 10^-14 M
The acid dissociation constant (Ka) is used to differentiate between strong and weak acids. Strong acids have very high Ka values. The Ka value is determined by examining the equilibrium constant for acid dissociation. The acid dissociates more readily as the Ka increases.
The original molecular definition of an acid, according to Arrhenius, is a molecule that dissociates in an aqueous solution, releasing the hydrogen ion H+ (a proton): HA A + H+. acid dissociation constant is an equilibrium constant for this dissociation reaction.
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The reaction between the reactants would be:
CH₃NH₂ + HCl ↔ CH₃NH₃⁺ + Cl⁻
Let the conjugate acid undergo hydrolysis. Then, apply the ICE approach.
CH₃NH₃⁺ + H₂O → H₃O⁺ + CH₃NH₂
I 0.11 0 0
C -x +x +x
E 0.11 - x x x
Ka = [H₃O⁺][CH₃NH₂]/[CH₃NH₃⁺]
Since the given information is Kb, let's find Ka in terms of Kb.
Ka = Kw/Kb, where Kw = 10⁻¹⁴
So,
Ka = 10⁻¹⁴/5×10⁻⁴ = 2×10⁻¹¹ = [H₃O⁺][CH₃NH₂]/[CH₃NH₃⁺]
2×10⁻¹¹ = [x][x]/[0.11-x]
Solving for x,
x = 1.483×10⁻⁶ = [H₃O⁺]
Since pH = -log[H₃O⁺],
pH = -log(1.483×10⁻⁶)
<em>pH = 5.83</em>
Answer: 2. cannot be an element.
Explanation:
Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Copper 
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: methane 
Thus as it can be decomposed into its constituent elements, it is a compound.
Mixture is a substance which has two or more components which do not combine chemically and do not have any fixed ratio in which they are present.
Thus methane cannot be an element.
