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dangina [55]
3 years ago
5

Sodium hydroxide (NaOH) was added to pure water (H2O). Which most likely were the pH values of the water before and after the so

dium hydroxide was added to it?
A. before = 7, after = 9
B. before = 7, after = 4
C. before = 4, after = 7
D. before = 9, after = 7
Physics
2 answers:
Anastaziya [24]3 years ago
3 0
Before 7 after 9. A pH smaller than 7 indicates acidity with 0 being completely acidic. A pH greater than 7 shows alkalinity with 14 being completely alkaline. 7 is neutral. Since NaOH is alkaline, adding it to a neutral substance would increase the pH and it would increase from 7 to 9.
Otrada [13]3 years ago
3 0

Answer: before=7 after=9

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Balok diam diatas bidang miring pada sudut kemiringan 40° balok mulai bergerak,tentukan koefisien gesek statis antara balok dan
Pachacha [2.7K]

Answer:

0.84

Explanation:

m = Massa balok

g = Percepatan gravitasi

\theta = Sudut kemiringan

\mu = Koefisien gesekan statik antara balok dan bidang miring

Gaya balok karena beratnya diberikan oleh

F=mg\sin\theta

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f=\mu mg\cos\theta

Kondisi dimana balok mulai bergerak adalah ketika gaya balok akibat beratnya sama dengan gaya gesek pada balok.

mg\sin\theta=\mu mg\cos\theta\\\Rightarrow \mu=\dfrac{mg\sin\theta}{mg\cos\theta}\\\Rightarrow \mu=\tan\theta\\\Rightarrow \mu=\tan40^{\circ}\\\Rightarrow \mu=0.84

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7 0
3 years ago
Why are there so few eclipses in 2014?
Sonbull [250]

Answer:

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Explanation:

8 0
3 years ago
Read 2 more answers
A large power plant heats 1917 kg of water per second to high-temperature steam to run its electrical generators.
erastova [34]

Complete Question

A large power plant heats 1917 kg of water per second to high-temperature steam to run its electrical generators.

(a) How much heat transfer is needed each second to raise the water temperature from 35.0°C to 100°C, boil it, and then raise the resulting steam from 100°C to 450°C? Specific heat of water is 4184 J/(kg · °C), the latent heat of vaporization of water is 2256 kJ/kg, and the specific heat of steam is 1520 J/(kg · °C).

J

(b) How much power is needed in megawatts? (Note: In real power plants, this process occurs under high pressure, which alters the boiling point. The results of this problem are only approximate.)

MW

Answer:

The heat transferred is  Q = 5.866 * 10^9 J

The power is  P = 5866\  MW

Explanation:

From the question we are told that

      Mass of the water per second is m = 1917 \ kg

      The initial temperature of the water is T_i  = 35^oC

      The boiling point of water is  T_b = 100^oC

      The final temperature T_f = 450^oC

      The latent heat of vapourization of water is  c__{L}} = 2256*10^3 J/kg

      The specific heat of water c_w = 4184 J/kg^oC

      The specific heat of stem is C_s =1520 \ J/kg ^oC

Generally the heat needed each second is mathematically represented as

         Q = m[c_w (T_i - T_b) + m* c__{L}}  + m* c__{S}} (T_f - T_b)]

Then substituting the value

        Q = m[c_w [T_i - T_b] + c__{L}}  + C__{S}} [T_f - T_b]]

         Q = 1917 [(4184) [100 - 35] + [2256 * 10^3]  +[1520]  [450 - 100]]

         Q = 1917 * [3.05996 * 10^6]

         Q = 5.866 * 10^9 J

The power required is mathematically represented as

         P = \frac{Q}{t}

From the question t = 1\ s

So  

        P = \frac{5.866 *10^9}{1}

        P = 5866*10^6 \ W

        P = 5866\  MW

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How to find the gradient of a velocity time graph
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The area-

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7 0
4 years ago
Tom says that insulation keeps out the cold. Explain why this statement is incorrect. What should Tom have said?
Zina [86]
There is no such thing as"cold", in the same way that there is no such thing
as "darkness" or "quietness".  "Darkness" is the absence of light, "quietness"
is the absence of sound, and "cold" is the absence of heat.

Tom should have said that insulation <em>keeps the heat in</em> .
4 0
3 years ago
Read 2 more answers
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