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3 years ago

What is atomic theory

1 answer:

8 0

The atomic theory is the scientific theory that matter is composed of particles called atoms. Atomic theory traces its origins to an ancient philosophical tradition known as atomism.

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How many moles of water h2o are present in 75.0 g h2o?

nikklg [1K]

4.17 moles. Good luck! :)

7 0

3 years ago

In what situation do we use a volumetric flask, conical flask, pipette and graduated cylinder? Explain your answer from accuracy

Ad libitum [116K]

A volumetric flask is used to contain a predetermined volume of substance and only measures that volume, for example 250 ml.
Conical flasks can be used to measure the volume of substances but the accuracy they provide is usually up to 10ml. Conical flasks are used in titrations, reactions where the liquid may boil, and reactions which involve stirring.
Pippettes are of two types, volumetric and graduated. Pippettes are used where high accuracy is required and volumetric pippettes come in as little as 1 ml. Pippettes are usually used in titrations.
Graduated cylinders come in a wide variety of sizes and their accuracy can be down to as much as 1 ml. They are used to contain liquids.

3 0

3 years ago

Element X has a charge of +2 and Element Y has a charge of -1.

bekas [8.4K]

the chemical equation will be XY2

6 0

3 years ago

How much heat is required to change the temperature of 100 grams of water from 25 to 55oc?

marysya [2.9K]

Hthe heat required to change the temperfature of 100 grams of water from 25 to 55 c is calculated as below

Q(heat) = M(mass) x C(specific heat capacity) x delta T(change in temperature)

M= 100 grams
C= 4.18 j/g/c
delta T= 55-25 =30c

Q=100 g x4.814 j/g/c x 30c = 12552 joules

5 0

3 years ago

A compound with molecular formula C5H10O2 has the following 1H NMR spectrum: 1.15 (t, 3H), 1.25 (t, 3H), 2.33 (q, 2H), 4.13 (q,

Vilka [71]

Answer:

Ethyl propionate

Explanation:

Calculating the double bond equivalence as:

DBE = C - (H/2) - (X/2) + (N/2) +1

Where

C is the number of carbon atoms

N is the number of nitrogen atoms

X is the number of halogens

H is the number of hydrogen atoms

So, according to the formula, $C_5H_{10}O_2$

DBE = 5 - (10/2) - (0/2) + (0/2) +1 = 1

It means there is one double bond or one ring.

from the NMR signal, it is clear that compound has two triplet and two quardrate group that means two -CH3 and two -CH2 groups are present.

From the splitting information, it is clear that each the -CH2- group is next to a -CH3, and vice-versa. In this case ring structure is not possible.

The chemical shift of two protons 4.13 ppm(q, 2H) is for protons next to an O atom, therefore, compound must have

$-OCH_2CH_3$ .

Then the signal at 2.33 is for a -CH2-group next to a C=O. So compound must have a structure CH3-CH2-C=O. Now, there is only one way to complete the structure - by bonding the O to the C=O carbon.

So the compound is ethyl propionate

3 0

3 years ago