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3 years ago

Sadie knows that the school record for the 100-meter dash is 18 seconds. During last weekend's race, the track coach time

Chemistry

2 answers:

posledela3 years ago

4 0

Answer:

JUAN AND KEITH ONLY!!!

Explanation:

Tju [1.3M]3 years ago

3 0

Answer: Keith and Aaron only

Explanation:

Since the school record for the 100-meter dash is 18 seconds, while

Juan did 19 seconds;

Hans did 16 seconds;

Keith did 17 seconds; and

Aaron did ILELE (unknown value)

Based on this illustration, only Keith and Aaron finished the 100-meter race at a lesser time than the school record.

Thus, Keith and Aaron only are the students that have broken the school record.

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A chemical reaction produces 138 mol of HBr gas. What volume will that gas occupy at STP?

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A buffer solution contains 0.479 M NaHCO3 and 0.342 M Na2CO3. Determine the pH change when 0.091 mol HNO3 is added to 1.00 L of

pshichka [43]

Answer:

ΔpH = 0.20

Explanation:

The buffer of HCO₃⁻ + CO₃²⁻ has a pka of 10.2

HCO₃⁻ ⇄ H⁺ + CO₃²⁻

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0.091 moles of NaOH produce the same moles of CO₃²⁻ and consume HCO₃⁻. Moles of these species are:

CO₃²⁻: 0.342mol + 0.091mol: 0.433mol

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Using Henderson-Hasselbalch formula:

pH = pka + log [Base] / [Acid]

pH = 10.2 + log 0.433mol / 0.388mol

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I hope it helps!

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2 years ago

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What pressure is exerted on the bottom of a 0.500-m-wide by 0.900-m-long gas tank that can hold 50.0 kg of gasoline by the weigh

Natasha_Volkova [10]

Answer:

1088.89 Pa

Explanation:

According to the Newton's second law of motion:-

$Force=Mass\times Acceleration$

Mass = 50.0 kg

Acceleration = g = 9.81 m/s²

So,

$Force=50.0\times 9.8\ kgm/s^2$

Force = 490 N

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Pressure = Force/Area = $\frac{490\ N}{0.45\ m^2}$ = 1088.89 Pa

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