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3 years ago

A runner completes a 400-meter race in 2.5 mins. What is the runner's average speed?

Chemistry

1 answer:

NNADVOKAT [17]3 years ago

8 0

The average speed is 160 meters a minute.

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A buffer solution is composed of 7.50 mol of acid and 4.75 mol of the conjugate base. If the pKa of the acid is 4.90 , what is t

Mamont248 [21]

Answer:

The correct answer is: pH= 4.70

Explanation:

We use the <em>Henderson-Hasselbach equation</em> in order to calculate the pH of a buffer solution:

$pH= pKa + log \frac{ [conjugate base]}{[acid]}$

Given:

pKa= 4.90

[conjugate base]= 4.75 mol

[acid]= 7.50 mol

We calculate pH as follows:

pH = 4.90 + log (4.75 mol/7.50 mol) = 4.90 + (-0.20) = 4.70

7 0

3 years ago

Among these element groups, which is least likely to form ions?

cupoosta [38]

Your answer would be 7A

3 0

4 years ago

Elements that have complete valence electron shells are mostly found in the

nika2105 [10]

Noble gases have complete valence electron shells

6 0

3 years ago

Read 2 more answers

The absorbance (????)(A) of a solution is defined as ????=log10(????0????) A=log10⁡(I0I) where ????0I0 is the incident‑light int

bulgar [2K]

Answer:

The absorbance of the myoglobin solution across a 1 cm path is 0.84.

Explanation:

Beer-Lambert's law :

Formula used :

$A=\epsilon \times c\times l$

$A=\log \frac{I_o}{I}$

$\log \frac{I_o}{I}=\epsilon \times c\times l$

where,

A = absorbance of solution

c = concentration of solution

$\epsilon$ = Molar absorption coefficient

l = path length

$I_o$ = incident light

$I$ = transmitted light

Given :

l = 1 cm, c = 1 mg/mL , $\epsilon = 15,000 M^{-1}cm^{-1}$

Molar mass of myoglobin = 17.8 kDa = 17.8 kg/mol=17800 g/mol

(1 Da = 1 g/mol)

c = 1 mg /mL = ${1mg /mL}{\text{Molar mass of myoglobin}}$

$c = \frac{1 mg/mL}{ 17800 g/mol} = 5.6179\times 10^{-5} mol/L$

1 mg = 0.001 g, 1 mL = 0.001 L

$A= 15,000 M^{-1}cm^{-1}\times 5.6179\times 10^{-5} mol/L\times 1 cm$

$A=0.8426 \approx 0.84$

The absorbance of the myoglobin solution across a 1 cm path is 0.84.

5 0

4 years ago

In order to rinse the system of exhaled C02 and meet the inspiratory flow rate requirements of infants placed on B-CPAP, the flo

LuckyWell [14K]

Answer:

In order to rinse the system of exhaled CO2 and meet the inspiratory flow rate requirements of infants placed on B-CPAP, the flow rate of humidified gas should be set at:

A. 16 to 20 L/minute

B. 6 to10 L/minute

C. at least 15 L/minute

D. 11 to 15 L/minute

B. 6 to10 L/minute

Explanation:

Bubble CPAP is a non-invasive, external ventilation technique used for newborn babies with infant respiratory distress syndrome (IRDS). Continuous positive airway pressure (CPAP) is given to a spontaneously breathing newborn baby to preserve lung volumes during expiration

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3 years ago