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lora16 [44]
2 years ago
12

A Teacher had her students write down hypothesis about an experiment. Which is a valid hypothesis? (1 point)

Chemistry
1 answer:
just olya [345]2 years ago
7 0

Answer:

You need to add the options to this question.

Explanation:

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Janice bought 40 shares of stock at $31.82 per share. She received dividends of $1.11 per share for 1 year. (Do not use commas,
Alborosie

Answer:

  • $30.71 per share

Explanation:

The <em>purchase price</em> is what Janice invested for every share.

Since the stock was priced at $31.82 per share and she received a $1.11 dividend per share, her investment was:

  • $31.82 - $1.11 = $30.71 per share ← answer

This price is the cost for Janice, over which she shall calculate their returns (gains or losses) on the future, when she sells the shares, for instance.

The total investment of Janice was the number of shares multipled by the purchase price:

  • 40 shares × ($31.82 -  $1.11)/ share
  • 40 shares × ($30.71) / share = $1,228.40 (total investment)
5 0
2 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
2 years ago
Speed is the ratio between distance and <br><br> Pls answer ASP!!
natulia [17]

Answer: Explanation: Speed is simply velocity without a specified direction (speed is the magnitude of the velocity vector). Regardless of the two measurements, they both relate distance to time, but are slightly different. Instantaneous speed is the derivative of the total distance covered with respect to time.

Explanation: I hope this helps!

8 0
2 years ago
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Which type of molecule is shown below?
zubka84 [21]

Answer:

\boxed{\mathrm{Alkene}}

Explanation:

The hydrocarbon shown has a double bond. Hydrocarbons with double bonds are known as alkenes.

Cyclic alkanes have cyclic structure.

Alkanes only have single bonds.

Alkynes have triple bonds.

8 0
3 years ago
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As an electron in an atom moves from a higher energy state to a lower energy state, the atom
Verdich [7]

Answer:B

Explanation:

5 0
2 years ago
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