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2 years ago

What is the periodic table and why is it neccessary?

Chemistry

1 answer:

wlad13 [49]2 years ago

6 0

Answer:

The periodic table is a table displaying each element and information about the elements, for example atomic number and chemical properties. This is necessary because without it it would be very hard to find information on the elements.

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What kind of changes occur between atoms when substances undergo chemical reactions?

KatRina [158]

The atoms undergo chemical changes.

New substances may be a product of the reaction.

8 0

3 years ago

If you have a solution that contains 46.85 g of codeine, C18H21NO3, in 125.5 g of ethanol, C2H5OH, what is the mole fraction of

irakobra [83]

Answer:

0.22

Explanation:

Given, Mass of $C_{18}H_{21}NO_3$ = 46.85 g

Molar mass of $C_{18}H_{21}NO_3$ = 299.4 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$Moles= \frac{46.85\ g}{299.4\ g/mol}$

$Moles\ of\ C_{18}H_{21}NO_3= 0.1565\ mol$

Given, Mass of $C_{2}H_{5}OH$ = 125.5 g

Molar mass of $C_{2}H_{5}OH$ = 46.07 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$Moles= \frac{125.5\ g}{46.07\ g/mol}$

$Moles\ of\ C_{2}H_{5}OH= 0.5535\ mol$

So, according to definition of mole fraction:

$Mole\ fraction\ of\ codeine=\frac {n_{codeine}}{n_{codeine}+n_{ethanol}}$

$Mole\ fraction\ of\ codeine=\frac{0.1565}{0.1565+0.5535}=0.22$

4 0

2 years ago

Please help me with all the questions and needs to be right thank u

murzikaleks [220]

Answer:

7. b

8. d

9. c

10. c

11. d

Explanation:

4 0

3 years ago

How many molecular orbitals would be present in a molecule with the formula: ch2o?

Zigmanuir [339]

There are two molecular orbitals in the CH2O or formaldehyde. These are designated by the two types of bonding involved. The first is the sigma bonding. It is the head-on overlap of electrons of the C and H atoms. The second molecular orbital is formed from the pi orbital bonding. This is a sideway overlap of electrons between C-O bonding.

7 0

2 years ago

A whale is swimming in the ocean. It communicates with another whale by sending out a sound. Which of the following best

ludmilkaskok [199]

Answer:

The sound is transmitted through water until it reaches the other whale.

Explanation:

When one whale makes a sound, the sound is transmitted through water until it reaches the other whale. The sound causes a ripple-like effect in the water, producing waves that travel in the water. The waves are heard in all directions. This is why humans can hear the sounds animals make underwater.

6 0

2 years ago