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ahrayia [7]
3 years ago
11

Mengapa air panas maupun air dingin yang disimpan di dalam termos cenderung lebih tahan lama suhu panas atau dinginnya

Chemistry
1 answer:
Zarrin [17]3 years ago
5 0
Yes yes yes yes yes yes yes yes yes yes
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Where is glycogen stored? (choose all that apply)<br> muscles<br> bones<br> organs<br> skin
Yuliya22 [10]
Muscles bones no on organs and no on skin
6 0
3 years ago
determine the ph of a buffer that is 0.55 M HNO2 and 0.75 M KNO2. tha value of Ka for HNO2 is 6.8*10^-4
Mariana [72]

Answer:

pH = 3.3

Explanation:

Buffer solutions minimize changes in pH when quantities of acid or base are added into the mix. The typical buffer composition is a weak electrolyte (wk acid or weak base) plus the salt of the weak electrolyte. On addition of acid or base to the buffer solution, the solution chemistry functions to remove the acid or base by reacting with the components of the buffer to shift the equilibrium of the weak electrolyte left or right to remove the excess hydronium ions or hydroxide ions is a way that results in very little change in pH of the system. One should note that buffer solutions do not prevent changes in pH but minimize changes in pH. If enough acid or base is added the buffer chemistry can be destroyed.

In this problem, the weak electrolyte is HNO₂(aq) and the salt is KNO₂(aq). In equation, the buffer solution is 0.55M HNO₂ ⇄ H⁺ + 0.75M KNO₂⁻ . The potassium ion is a spectator ion and does not enter into determination of the pH of the solution. The object is to determine the hydronium ion concentration (H⁺) and apply to the expression pH = -log[H⁺].

Solution using the I.C.E. table:

              HNO₂ ⇄    H⁺   +   KNO₂⁻

C(i)        0.55M       0M      0.75M

ΔC            -x            +x          +x

C(eq)  0.55M - x       x     0.75M + x    b/c [HNO₂] / Ka > 100, the x can be                                    

                                                             dropped giving ...

           ≅0.55M        x       ≅0.75M        

Ka = [H⁺][NO₂⁻]/[HNO₂] => [H⁺] = Ka · [HNO₂]/[NO₂⁻]

=> [H⁺] = 6.80x010⁻⁴(0.55) / (0.75) = 4.99 x 10⁻⁴M

pH = -log[H⁺] = -log(4.99 x 10⁻⁴) -(-3.3) = 3.3

Solution using the Henderson-Hasselbalch Equation:

pH = pKa + log[Base]/[Acid] = -log(Ka) + log[Base]/[Acid]

= -log(6.8 x 10⁻⁴) + log[(0.75M)/(0.55M)]

= -(-3.17) + 0.14 = 3.17 + 0.14 = 3.31 ≅ 3.3

3 0
3 years ago
A 1.00 L volume of HCl reacted completely with 2.00 L of 1.50 M Ca(OH)2 according to the balanced chemical equation below. 2HCl
Zigmanuir [339]
The first step is to find the number of moles of OH⁻ that reacted with the HCl.  To do this multiply 2.00L by 1.50M to get 3 moles of Ca(OH)₂.  Then you multiply 3 by 2 (there are 2 moles of OH⁻ per every 1 mole of Ca(OH)₂) to get 6 moles of OH⁻.  That means that you needed 6 moles of HCl since 1 mole of HCl contains 1 mole of H⁺ and equal amounts H⁺ and OH⁻ reacted with each other.  To find the molarity of the HCl solution you need to divide 6mol by 1L to get 6M.  Tat means that the concentration of the acid was 6M.

I hope this helps.  Let me know if anything was unclear.
5 0
3 years ago
Read 2 more answers
What are the chemical names for KF
den301095 [7]
Um, I think it’s: k is potassium and F is fluorine so potassium Fluoride
7 0
3 years ago
Use the portion of the periodic table shown below to answer the questions
leva [86]

Answer:

Part 1:sodium

rubidium

Part 2: protons neutrons and electrons are all 12

The number of protons is equal to the no. of neutrons from the electronic arrangement of magnesium and the no. of electrons is got from the atomic no. of magnesium

8 0
3 years ago
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