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A student was given a sample of crude acetanilide to recrystallize. The initial mass of the the crude acetanilide was 166 mg. Th

padilas [110]

Answer:

The percentage of mass recover from recrystallization = 24.69 %

Explanation:

Given that

Initial mass of crude acetanilide = 166 gm

The mass after recrystallization = 125 gm

The mass recover from recrystallization= 166 - 125 gm

The mass recover from recrystallization= 41 gm

The percentage of mass recover from recrystallization can be find as

$percentage\ of\ mass\ recover\ from\ recrystallization\ =\dfrac{166-125}{166}$

The percentage of mass recover from recrystallization = 24.69 %

4 0

3 years ago

A cart is driven by a large propeller or fan, which can accelerate or decelerate the cart. The cart starts out at the position x

mash [69]

Answer:

The acceleration of the cart is 1.0 m\s^2 in the negative direction.

Explanation:

Using the equation of motion:

Vf^2 = Vi^2 + 2*a*x

2*a*x = Vf^2 - Vi^2

a = (Vf^2 - Vi^2)/ 2*x

Where Vf is the final velocity of the cart, Vi is the initial velocity of the cart, a the acceleration of the cart and x the displacement of the cart.

Let x = Xf -Xi

Where Xf is the final position of the cart and Xi the initial position of the cart.

x = 12.5 - 0

x = 12.5

The cart comes to a stop before changing direction

Vf = 0 m/s

a = (0^2 - 5^2)/ 2*12.5

a = - 1 m/s^2

The cart is decelerating

Therefore the acceleration of the cart is 1.0 m\s^2 in the negative direction.

5 0

3 years ago

A new "smart" refrigerator has been designed with sensors that send information to the manufacturer about the refrigerator's use

zysi [14]

Answer:

internet of things.

Explanation:

The mention Smart refrigerator with information communication system to both manufacturer as well as the customer is an example of internet of things.

The interconnection via internet of computing devices embedded in everyday objects, enabling them to send and receive data. It is also the ability to transfer data without human to human or computer to human interaction.

6 0

4 years ago

An insulated Thermos contains 140 cm3 of hot coffee at 85.0°C. You put in a 15.0 g ice cube at its melting point to cool the cof

Pavel [41]

Answer:

$T = 69^o C$

Explanation:

Here at thermal equilibrium we can say that thermal energy given by Hot coffee is equal to the thermal energy absorbed by ice cubes

So here we have

$Q_{ice} = Q_{coffee}$

now since ice cubes are added into coffee when it is at melting temperature

So here we can say that final temperature of coffee is T degree C

Now we have

$m_1L + m_1c_1\Delta T_1 = m_2c_2\Delta T_2$

here we have

$m_1 = 15 gram$

L = 333 kJ/kg = 333 J/g[/tex]

$c_1 = c_2 = 4186 J/kg C = 4.186 J/g C$

$\Delta T_1 = T - 0$

$\Delta T_2 = 85 - T$

now we have

$15(333) + 15(4.186)(T - 0) = 140(4.186)(85 - T)$

$4995 + 62.79T = 49813.4 - 586.04T$

$648.83 T = 44818.4$

$T = 69^o C$

6 0

3 years ago

Consider the concepts of kinetic energy (KE) and gravitational potential energy (GPE) as you complete these questions. A ball is

Lena [83]

Answer:

When the ball is held motionless above the floor, the ball possesses only GPE energy.If the ball is dropped, its GPE energy decreases as it falls.If the ball is dropped, its KE energy increases as it falls.

Explanation:

If the ball is held motionless, then its kinetic energy is equal to zero, since kinetic energy depends on the velocity. And the ball is held above the ground, which means it possesses gravitational potential energy.

If the ball is dropped, its height will decrease, therefore its gravitational potential energy will decrease. Along the way, the ball will be in free fall, and therefore its velocity will increase, hence its kinetic energy.

$K = \frac{1}{2}mv^2\\U = mgh$

3 0

3 years ago