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3 years ago

Is the following hypothesis testable? "If I study, I will get a better grade on a test than if I do not study."

Chemistry

1 answer:

Fudgin [204]3 years ago

4 0

Answer:

Yes

Explanation:

Yes, you can test this by comparing grades you received when you studied and when you did not study

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Two Carnot engines are operated in series with the exhaust (heat output) of the first engine being the input of the second engin

OlgaM077 [116]

Answer:

(a) 140 F

(b) The temperature rise at the point where the heat is dumped is 2.51 degC

Explanation:

(a) Considering T1 the temperature of input of the first engine, T2 the temperature of the exhaust of the first engine (and input of the second engine) and T3 the exhaust of the second engine, if both engines have the same efficiency we have:

$\eta=1-\frac{T_1}{T2}=1-\frac{T_2}{T_3}$

The temperatures have to be expressed in Rankine (or Kelvin) degrees

$1-\frac{T_1}{T2}=1-\frac{T_2}{T_3}\\\\\frac{T_1}{T2}=\frac{T_2}{T_3}\\\\(T_2)^{2} =T_1*T_3\\\\T_2=\sqrt{T_1*T_3} =\sqrt{(459.67+260)*(459.67+40)}= \sqrt{719.67*499.67}\\\\ T_2=599 \, R= (599-459.67) ^{\circ} F=140^{\circ} F$

(b) The Carnot efficiency of the cycle is

$\eta_{c}=1-Th/Ts=1-(273+20)/(273+315)=0.502$

If the efficiency of the plant is 60% of the Carnot efficiency, we have

$\eta=0.6*\eta_{c}=0.6*0.502=0.302$

The heat used in the plant can be calculated as

$Q_i=W/\eta=750MW/0.302=2483MW$

And the heat removed to the heat sink is

$Q_o=Qi-W=2483-750=1733MW$

If the flow of the river is 165 m3/s, the heat per volume in the sink is

$\frac{Q_o}{f} =\frac{1733 MJ/s}{165 m3/s}= 10.5MJ/m3$

Considering a heat capacity of water C=4.1796 kJ/(kg*K) and a density ρ of 1000 kg/m3, the temperature rise of the water is

$\Delta Q=C*\Delta T\\\Delta T=(1/C)*\Delta Q\\\Delta T=(\frac{1}{4.1796\frac{kJ}{kgK} } )*10,500\frac{kJ}{m3}*\frac{1m3}{1000kg}\\\Delta T= 2.51 ^{\circ}C$

8 0

4 years ago

Which metal is more active Ni and less active than Zn

arlik [135]

Is this a multiple choice?

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3 years ago

The chemical standard for the quantity of a mole is based on which substance?

alexandr402 [8]

A mole is mean the atomic number of 12 grams of carbon 12.

3 0

4 years ago

PLEASE HELP ME! What are some patterns or trends that are present in the table of elements?

Sati [7]

Some patterns and trend that are present in the periodic table would be

1. electronegativity (from left-to-right it increases across the table)

2. ionization (from left-to right it increases and from bottom-to-top it increases)

3. electron affinity (same as ionization energy)

4. atom radius (increases opposite way; from right-to-left it increases and from top-to-bottom it increases)

5. melting point (higher melting points with metals and lower melting point with non-metals)

6. metallic character (same as atom radius)

5 0

3 years ago

Seawater is mostly a solution of sodium chloride in water. The concentration varies, but marine biologists took a sample with an

sineoko [7]

Answer:

1.0.16

2.a.355mg

b. 8.07mmol/L

3.7.83%

Explanation:

3 0

3 years ago