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2 years ago

How do you work out how many atoms there are in a isotope?

1 answer:

4 0

206Pb = 1.342 x10^22 atoms

To find the number of atoms, you must first find the number of moles. If 238U is 238.029g/mol, and we have 1.75 grams, how many moles is that? 1.75 divided by 238.029 = 0.007352045 moles. To find the number of atoms in 0.007352045 moles, you multiply by a mole: 
0.007352045 x 6.02 x 10^23 = 4.426 x10^21 atoms. 

Same procedure for 206Pb: 
4.59 divided by 205.97446 = 0.022284316 moles 
0.022284316 x 6.02 x 10^23 = 1.342 x10^22 atoms. 

Hope that helps you!
https://answers.yahoo.com/question/index?qid=20100331153014AAoMXcu

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Which of the following describes the charge of an atom before any electrons are transferred?

gregori [183]

The answer is neutral charge. An atom element will always and has to be stable, in order for this state to happen. The charge of an electron has to be neutral. For atom with neutral charge, the proton will always equal the number of electron.

8 0

2 years ago

Can someone please help? Thank u!

Snowcat [4.5K]

Answer:

B. 7.5 m/s^2

Explanation:

To find acceleration you need to subtract the final velocity by the starting velocity then divide that by the time

a= v-v/t

a= 60-0/8

a= 60/8

a=7.5 m/s^2

7 0

2 years ago

A constant amount of charge passes through a conductor. How is current affected if the same amount of charge passes in less time

baherus [9]

Answer:

B. The current increases.

Explanation:

As we know that rate of flow of charge through the conductor is known as electric current

So we have

$i = \frac{q}{t}$

here we know that charge Q flowing through the conductor is constant while the time in which it passes through it is decreased

so we can say that the ratio of charge and time will increase

so here we have

$i = increased$

So correct answer will be

B. The current increases.

4 0

2 years ago

Physics question i appreciate your help please

den301095 [7]

Solution: From the given question, we shall find the vector quantity among the

(A) Time , (B) Velocity, (C) Distance , (D) Speed

Concept: Vector Quantity: All those physical quantities which have magnitude as well as specific directions, are called Vector Quantities.

Here, Time, Distance and Speed have only magnitude but have no directions so they will be scalar quantities.

Now, Velocity: It is defined as the change in displacement per unit time. Since the change in the displacement will be in particular direction only. Hence, velocity will be the vector quantity.

Hence, the option (B) Velocity will be the correct option.

4 0

2 years ago

A 1.0-cm-tall object is 13 cm in front of a converging lens that has a 40 cm focal length.

kicyunya [14]

A) Image position: -19.3 cm

B) Image height: 1.5 cm, upright

Explanation:

In order to calculate the image position, we can use the lens equation:

$\frac{1}{p}+\frac{1}{q}=\frac{1}{f}$

where

p is the distance of the object from the lens

q is the distance of the image from the lens

f is the focal length

In this problem, we have:

p = 13 cm (object distance)

f = 40 cm (focal length, positive for a converging lens)

So the image distance is

$\frac{1}{q}=\frac{1}{f}-\frac{1}{p}=\frac{1}{40}-\frac{1}{13}=-0.0519\\q=\frac{1}{-0.0519}=-19.3 cm$

The negative sign means that the image is virtual.

In order to calculate the image height, we use the magnification equation:

$\frac{y'}{y}=-\frac{q}{p}$

where

y' is the image height

y is the object height

In this problem, we have:

y = 1.0 cm (object height)

p = 13 cm

q = -19.3 cm

Therefore, the image heigth is

$y'=-\frac{qy}{p}=-\frac{(-19.3)(1.0)}{13}=1.5 cm$

And the positive sign means the image is upright.

6 0

2 years ago