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3 years ago

14

A sample originally contains 24 grams of a radioactive isotope. After 18 days, 18.8 grams of the isotope remain in the sample. W

hat is the half-life of the isotope

1 answer:

LenKa [72]3 years ago

8 0

Around 36 or 37 days, because of the decimal

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What is covalent bond

katen-ka-za [31]

Covalent bonding is when electrons are shared between atoms.

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3 years ago

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Calculate the amount of time required to raise temperature of 0.50 liter of water from

Burka [1]

<h3>Answer:</h3>

19 seconds

<h3>Explanation:</h3>

Heat energy was supplied and used to heat 0.50 liters of water from 0°C to 10°C.

This means water gained heat energy that was supplied.

Therefore;

Heat supplied = Heat gained by water

We are required to calculate the time taken to raise the temperature of water from 0°C to 10°C.

Step 1: Calculate the heat gained by water

Quantity of heat = Mass × specific heat capacity × change in temperature

Density of water 1 g/ml

Volume of water is 500 mL

Therefore, since Mass = density × volume

The mass of water = 500 g

Change in temperature = 10° C

Specific heat capacity of water = 4.18 J/g/°C

Thus;

Quantity of heat = 500 g × 4.18 J/g/°C × 10

= 20,900 Joules

Step 2: Heat supplied by a heater

Heat supplied = Power × time

Power = 1100 J/s

Assuming the time required is x

Heat supplied = 1100x Joules

Step 3: Time required

Remember; heat supplied = heat gained by water

Therefore;

1100x joules = 20,900 Joules

x = 20,900/1100

= 19 seconds

Therefore, the time required to raise the temperature of water from 0°C to 10°C is 19 seconds.

6 0

3 years ago

a student carries out this chemical reaction in a beaker: Zn+CuCl2-->Cu+ZnCl2 After the reactionhas come to completion, what

BigorU [14]

Answer:

The correct answer is

C. Cu and ZnCl2

Explanation:

I got it correct on PLATO

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3 years ago

Jill then wrote the formulas for all the possible compounds that sodium can form with the other ions. What formulas did she writ

sp2606 [1]

Explanation:

Sodium has atomic number of 11 and its electronic configuration is given by:

$[Na]=1s^22s^22p^63s^1$

The nearest stable electronic configuration to sodium is of the neon. So, in order to attain stability of noble gas it will loose its single electron.

$Na\rightarrow Na^++1e^-$

$[Na^+]=1s^22s^22p^63s^0$

Sodium has single valency that is 1.

Let nbe the valency of the ion 'X'

By criss-cross method, the oxidation state of the ions gets exchanged and they form the subscripts of the other ions. This results in the formation of a neutral compound.

$Na_nX_1$

So, the formulas for all the possible compounds that sodium can form with the other ions will be:

$Na_nX_1$

4 0

3 years ago

Plz help <br> Plz and thank u

Veseljchak [2.6K]

D Excretory systems regulate the chemical composition of body fluids by removing metabolic wastes and retaining the proper amounts of water, salts, and nutrients. Components of this system in vertebrates include the kidneys, liver, lungs, and skin.

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