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larisa86 [58]
3 years ago
13

Who was the first person to propose that atoms existed?

Chemistry
2 answers:
Gennadij [26K]3 years ago
8 0
Democritus was the first person to theorize the existence of atoms.
levacccp [35]3 years ago
7 0

Remember we are just talking about proposals, not actual evidence. So it would be Democritus.

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How much mass defect is required to release 5.5 x 1020 J of energy?
Montano1993 [528]

Answer : The mass defect required to release energy is 6111.111 kg

Explanation :

To calculate the mass defect for given energy released, we use Einstein's equation:

E=\Delta mc^2

E = Energy released = 5.5\times 10^{20}J

\Delta m = mass change = ?

c = speed of light = 3\times 10^8m/s

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

5.5\times 10^{20}Kgm^2/s^2=\Delta m\times (3\times 10^8m/s)^2

\Delta m=6111.111kg

Therefore, the mass defect required to release energy is 6111.111 kg

5 0
3 years ago
Why are the properties of a compound different than the elements that make it up.
nexus9112 [7]

The properties of compounds are different, and in some cases very different, from those of the elements that compose them. This is because elements combine in compounds to become completely different substances with unique properties.

Compounds contain atoms of different elements chemically bonded in fixed ratios. An element is a pure chemical substance made up of atoms of the same kind. Compounds contain different elements in fixed ratios, arranged in a defined way by chemical bonds.

This is caused by different base properties where each element has a different number. Due to the number of electrons and differences in shell and valence electrons, different elements bond differently to certain other elements.

Compounds:

is composed of atoms of two or more different elements bonded together, and

can be broken down into simpler types of matter (elements) by chemical (rather than physical) means. from its components, and.

always contains the same proportions of atomic components.

Learn more about elements combine here;

brainly.com/question/6258301

#SPJ4

3 0
1 year ago
In testing the effectiveness of an antacid compound, 20.0g of Hydrochloric Acid is mixed with 28.0g of Magnesium Hydroxide. Will
BartSMP [9]

Answer:

Base Mg(OH)2 does neutralise the acid and is 12g in excess.

Explanation:

2HCL +Mg(OH)2 -> MgCl2 + 2H20

2 * 36.458 g of HCL react with  58.319 g of  Mg(OH)2 to neutralise it.

72.916 HCl reacts with  58.319 g of the base.

So 20 g HCl reacts with  (58.319/72.916) * 20 = 16g.

There are 28 g of Mg(OH)2 so the base does neutralise all the acid.

The Mg(OH)2 is 28 - 16 = 12 g in excess.

4 0
3 years ago
Why does the particle of water at 0 degree celcius have more energy as cimparrd to the particles in ice at the same temperature?
jekas [21]
There is Kinetic energy involved in the state something is in. The molecules in a liquid are moving around quicker than those in a solid. 

That's one reason.

The ice requires energy to melt. Bonds must be broken to get from a solid to a liquid.

5 0
3 years ago
0.22 L of HNO3 is titrated to equivalence using 0.10 L of 0.1 MNaOH. What is the concentration of the HNO3?
White raven [17]

Answer:- Molarity of the acid solution is 0.045M.

Solution:- The balanced equation for the reaction of given acid and base is:

HNO_3+NaOH\rightarrow NaNO_3+H_2O

From the balanced equation, they react in 1:1 mol ratio. So, we could easily solve the problem using the equation:

M_aV_a=M_bV_b

where, M_a is the molarity of acid, M_b is the molarity of base, V_a is the volume of acid and V_b is the volume of base.

Let's plug in the given values in the equation:

M_a(0.22L)=0.1M(0.10L)

on rearranging the above equation:

M_a=\frac{0.1M(0.10L)}{0.22L}

M_a = 0.045M

So, the molarity of the acid solution is 0.045M.

3 0
3 years ago
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