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Gwar [14]
3 years ago
8

A student measures the pH of a solution to be 6.8. Which should the student add if she wants to decrease the pH of the solution?

Physics
2 answers:
zloy xaker [14]3 years ago
7 0
The neutral pH is 7. Less than 7 indicates an acid and more than 7 indicates a base (up to 14).
<span> NaCl - it's a salt (we can't measure the pH)
H2O - it can be an acid but also a base  (the pH it is almost neutral,meaning close to 7 )
HF - it is a strong acid
</span><span> KOH  - it is a strong base (pH=14)
</span>
                        ↓

He needs to use HF (Hydrogen fluoride) to decrease the pH.


vichka [17]3 years ago
5 0
HF is the answer because it is an acid so it decreases overall ph. Did you understand?
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An ion in a mass spectrometer follows a semicircular path of radius 14.8. What is the distance it travels?
aleksklad [387]

The circumference of a circle is (2π · the circle's radius).

The length of a semi-circle is  (1π · the circle's radius) =

                                                 (π · 14.8) = 46.5 (rounded)

(The unit is the same as whatever the unit of the  14.8  is.)

7 0
3 years ago
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11. A 3.8 kg object is lifted 12 meters. Approximately how much work is performed during the lifting?
Marianna [84]
I found the answer for you if u need any help ask anytime!

3 0
3 years ago
If the PLATE SEPARATION of an isolated charged parallel-plate capacitor is doubled: A. the electric field is doubled
mash [69]

Explanation:

The electric field of an isolated charged parallel-plate capacitor is given by :

E=\dfrac{q}{A\epsilon_o}........(1)

Where

q is the electric charge

A is the area of cross section of parallel plate

It is clear from equation (1) that the electric field of a parallel plate capacitor is directly proportional to the charge on the plate and inversely proportional to the area of cross section of a plate.

So, the correct option is (E) i.e. "none of the above".

5 0
3 years ago
Which of the following is the best reason to rest muscle groups between workouts?
vovangra [49]

Answer;

It allows the muscles time to heal.

Explanation;

-It is very important to rest muscles between workouts. In fact, resistance training breaks down muscles causing microscopic tears. It is only during rest when the muscle-building process is stimulated and the regeneration of new tissue occurs.

-But when muscles are not allowed adequate rest and recover time, the regeneration process cannot occur. This can have several side effects such as increased soreness, decreased strength and performance, and may lead to injury.  

4 0
3 years ago
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An airplane propeller is 2.68 m in length (from tip to tip) and has a mass of 107 kg. When the airplane's engine is first starte
telo118 [61]

Answer:

a)30.14 rad/s2

b)43.5 rad/s

c)60633 J

d)42 kW

e)84 kW

Explanation:

If we treat the propeller is a slender rod, then its moments of inertia is

I =\frac{mL^2}{12} = \frac{107*2.68^2}{12} = 64.04 kgm^2

a. The angular acceleration is Torque divided by moments of inertia:

\alpha = \frac{T}{I} = \frac{1930}{64.04} = 30.14 rad/s^2

b. 5 revolution would be equals to 10\pi rad, or 31.4 rad. Since the engine just got started

\omega^2 = 2\alpha\theta = 2*30.14*31.4 = 1893.5

\omega = \sqrt{1893.5} = 43.5 rad/s

c. Work done during the first 5 revolution would be torque times angular displacement:

W = T*\theta = 1930 * 31.4 = 60633 J

d. The time it takes to spin the first 5 revolutions is

t = \frac{\omega}{\alpha} = \frac{43.5}{30.14} = 1.44 s

The average power output is work per unit time

P = \frac{W}{t} = \frac{60633}{1.44} = 41991 W or 42 kW

e.The instantaneous power at the instant of 5 rev would be Torque times angular speed at that time:

P_i = T*\omega = 1930*43.5=83983 W or 84 kW

7 0
3 years ago
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