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3 years ago

Who was the first scientist to develop a theory of the atom

Chemistry

2 answers:

Olegator [25]3 years ago

8 0

Democritus, a Greek philosopher.

PIT_PIT [208]3 years ago

5 0

Democritus if you want the VERY first. Whereas John Dalton proposed the idea of the atomic theory. :)

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Give three examples of monoatomic molecules.

umka2103 [35]

Answer:

Helium

Radon

and Neon

Explanation:

5 0

2 years ago

A collection of 6. 25×1018 electrons has the charge of.

Natali [406]

Answer:

Explanation:

1)The charge of one electron is given by

1 e = - 1.6 * 10-19 C

Then – 1 C = 1 e / ( 1.6 * 10-19 )

= 6.25 * 1018 e

So one-coulomb charge has 6.25 * 1018 electrons

2)Let q1 and q2 be two charges separated by a distance r

Then q1 = - 40 µC = - 40 * 10-6 C

And q2 = 108 µC = 108 * 10-6 C

7 0

2 years ago

At 25 °C, the equilibrium partial pressures for the following reaction were found to be PA = 8.00 atm, PB = 5.40 atm, PC = 6.90

Yuliya22 [10]

<u>Answer:</u> The standard change in Gibbs free energy for the given reaction is 4.33 kJ/mol

<u>Explanation:</u>

For the given chemical equation:

$A(g)+2B(g)\rightleftharpoons C(g)+D(g)$

The expression of $K_p$ for the given reaction:

$K_p=\frac{p_C\times p_D}{p_A\times (p_B)^2}$

We are given:

$p_A=8.00atm\\p_B=5.40atm\\p_C=6.90atm\\p_D=5.90atm$

Putting values in above equation, we get:

$K_p=\frac{6.90\times 5.90}{8.00\times (5.40)^2}\\\\K_p=0.174$

To calculate the standard Gibbs free energy, we use the relation:

$\Delta G^o=-RT\ln K_p$

where,

$\Delta G^o$ = standard Gibbs free energy

R = Gas constant = $8.314J/K mol$

T = temperature = $25^oC=[25+273]K=298K$

$K_p$ = equilibrium constant in terms of partial pressure = 0.174

Putting values in above equation, we get:

$\Delta G^o=-(8.314J/Kmol)\times 298K\times \ln (0.174)\\\\\Delta G^o=4332.5J/mol=4.33kJ/mol$

Hence, the standard change in Gibbs free energy for the given reaction is 4.33 kJ/mol

3 0

3 years ago

HURRY 10 POINTS!!!

BaLLatris [955]

Earths magnetic field is formed mostly by

B. SOLAR WIND

4 0

3 years ago

What caused the disappearance of land bridges? O A. Recession of glaciers and ice caps O B. Mountain building O C. Formation of

SashulF [63]

I say it’s OC cus well I don5 know I guess
Unless you actual need help or is this a test question for us to gu3ss right

5 0

2 years ago

Read 2 more answers