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3 years ago

If an isotope has 8 protons and 10 neutrons in it's nucleus, what is it's atomic mass?

1 answer:

8 0

The atomic mass is always equal to the sum of protons and neutrons in the nucleus. If you add the number of protons and neutrons (8 + 10) = 18 you will find that the atomic mass is 18.

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what is the value of the constant for a second order reaction if the reactant concentration drops from .657 M to ,0981 M in 17 s

yaroslaw [1]

Answer : The value of the constant for a second order reaction is, $0.51M^{-1}s^{-1}$

Explanation :

The expression used for second order kinetics is:

$kt=\frac{1}{[A_t]}-\frac{1}{[A_o]}$

where,

k = rate constant = ?

t = time = 17s

$[A_t]$ = final concentration = 0.0981 M

$[A_o]$ = initial concentration = 0.657 M

Now put all the given values in the above expression, we get:

$k\times 17s=\frac{1}{0.0981M}-\frac{1}{0.657M}$

$k=0.51M^{-1}s^{-1}$

Therefore, the value of the constant for a second order reaction is, $0.51M^{-1}s^{-1}$

6 0

3 years ago

Determine which heat transfers below are due to the process of conduction. I) You walk barefoot on the hot street and it burns y

Taya2010 [7]

Answer:

I) You walk barefoot on the hot street and it burns your toes.

II) When you get into a car with hot black leather in the middle of the summer and your skin starts to get burned.

Explanation:

In conduction mode of heat transfer we know that the energy is transferred from one system to other system due to direct contact of two bodies

Here due to this direct contact the energy is transferred via a given solid or liquid medium

In this type of heat transfer medium particles will remain in its own position only the energy is transferred.

So here we can say the correct answer will be

I) You walk barefoot on the hot street and it burns your toes.

II) When you get into a car with hot black leather in the middle of the summer and your skin starts to get burned.

3 0

3 years ago

How long was a 60 W light bulb turned on if it used a total of 580 J of energy?

icang [17]

Here's the tool you need. You can't answer the question without this:

   "1 watt"
means
   "1 joule of energy, generated, used, or moved, every second".

So 60 watts = 60 joules per second

   Total energy generated,
      used, or moved = (power) x (time).

   580 joules = (60 watts) x (time)

Divide each side
by (60 watts): Time = (580 joules) / (60 joules/sec)

   = (9 and 2/3) seconds .

7 0

3 years ago

I need help quick pls . Its either physical or chemical change !

Trava [24]

Physical, chemical, chemical, physical, I’m pretty sure. Natural things, like you starting to breathe heavier are physical most of the time!!!

8 0

3 years ago

A physics major is cooking breakfast when he notices that the frictional force between the steel spatula and the Teflon frying p

wel

Answer:

Normal force = 8.75 N

Explanation:

given,

frictional force between the steel spatula and the Teflon frying pan=0.350 N

coefficient of friction between material =0.04

normal force = ?

using formula,

Frictional force = coefficient of friction × normal force

$normal\ force = \dfrac{Frictional\ force}{coefficient\ of\ friction}$

$normal\ force = \dfrac{0.350}{0.04}$

Normal force = 8.75 N

8 0

3 years ago