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4 years ago

Classify each process according to direction of heat flow.

Chemistry

2 answers:

MrRissso [65]4 years ago

6 0

Answer:

heat flows in

heat flows out

Explanation:

Pavlova-9 [17]4 years ago

4 0

Answer: heat flows in

heat flows out

Explanation:

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In chemistry, to be classified as an organic substance, a substance must contain

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In chemistry, to be classified as an organic substance, a substance must contain carbon atoms

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Why does your heart rate increase while exercising?

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During exercise, your body may need three or four times your normal cardiac output, because your muscles need more oxygen when you exert yourself. During exercise, your heart typically beats faster so that more blood gets out to your body.

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One of the hazards of nuclear explosions is the generation of 90Sr andits subsequent incorporation in place of calcium in bones.

Illusion [34]

Explanation:

Initial mass of the isotope 90-Sr in baby= 1.00 μg

Formula used :

$N=N_o\times e^{-\lambda t}\\\\\lambda =\frac{0.693}{t_{\frac{1}{2}}}$

where,

$N_o$ = initial mass of isotope

N = mass of the parent isotope left after the time, (t)

$t_{\frac{1}{2}}$ = half life of the isotope = 28.1 years

$\lambda$ = rate constant

$N=N_o\times e^{-(\frac{0.693}{t_{1/2}})\times t}$

a) Time taken by the sample, t = 18 years

$N=1.00 \mu g\times e^{-\frac{0.693}{28.1 years}\times 18 years}$

$N = 0.6415 \mu g$

0.6415 μg will remain after 18 years.

b) Time taken by the sample, t = 70 years

$N=1.00 \mu g\times e^{-\frac{0.693}{28.1 years}\times 70 years}$

$N = 0.1779\mu g$

0.1779 μg will remain after 70 years.

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4 years ago

A sample of gas has a pressure of 3.2 atmospheres at a temperature of 301 Kelvin. What would be the pressure of the same sample

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P1/T1=P2/T2 Gay Lussac's Law

3.2/301=P2/285

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Ethylenediamine (en) forms an octahedral complex with Ni2+(aq) with the formula [Ni(en)3]2+. Ni2+(aq) + 3 en ⇌ [Ni(en)3]2+(aq) K

yawa3891 [41]

Answer:

$3.125\times 10^{-19} mol/L$ is the concentration of $Ni^{2+}(aq)$ in the solution.

Explanation:

$Ni^{2+}(aq) + 3 en\rightleftharpoons [Ni(en)_3]^{2+}(aq)$

Concentration of nickel ion = $[Ni^{2+}]=x$

Concentration of nickel complex= $[[Ni(en)_3]^{2+}]=\frac{0.16 mol}{2 L}=0.08 mol/L$

Concentration of ethylenediamine = $[en]=\frac{0.80 mol}{2 L}=0.40 mol/L$

The formation constant of the complex = $K_f=4.0\times 10^{18}$

The expression of formation constant is given as:

$K_f=\frac{[[Ni(en)_3]^{2+}]}{[Ni^{2+}][en]^3}$

$4.0\times 10^{18}=\frac{0.08 mol/L}{x\times (0.40 mol/L)^3}$

$x=\frac{0.08 mol/L}{4.0\times 10^{18}\times (0.40 mol/L)^3}$

$x=3.125\times 10^{-19} mol/L$

$3.125\times 10^{-19} mol/L$ is the concentration of $Ni^{2+}(aq)$ in the solution.

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4 years ago