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3 years ago

Who was the first person to come up with the idea of the "atom?"

Chemistry

1 answer:

defon3 years ago

4 0

Answer: Democritus

Explanation: Democritus was a Greek philosopher who was the first person to use the term atom(atomos: meaning indivisible). He thought that if you take a piece of matter and divide it and continue to divide it you will eventually come to a point where you could not divide it any more. This fundamental or basicunit was what Democritus called an atom.

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What is the volume of 0.80 grams of o2 gas at stp? (5 points) group of answer choices 0.59 liters 0.56 liters 0.50 liters 0.47 l

Vladimir [108]

Answer:

0.56L

Explanation:

This question requires the Ideal Gas Law: $PV=nRT$ where P is the pressure of the gas, V is the volume of the gas, n is the number of moles of the gas, R is the Ideal Gas constant, and T is the Temperature of the gas.

Since all of the answer choices are given in units of Liters, it will be convenient to use a value for R that contains "Liters" in its units: $R=0.0821\frac{L\cdot atm}{mol\cdot K}$

Since the conditions are stated to be STP, we must remember that STP is Standard Temperature Pressure, which means $T=273.15K$ and $P=1atm$

Lastly, we must calculate the number of moles of $O_2(g)$ there are. Given 0.80g of $O_2(g)$ , we will need to convert with the molar mass of $O_2(g)$ . Noting that there are 2 oxygen atoms, we find the atomic mass of O from the periodic table (16g/mol) and multiply by 2: $32g\text{ }O_2=1mol\text{ }O_2$

Thus, $\frac{0.80g \text{ }O_2}{1} \frac{1mol\text{ }O_2}{32g\text{ }O_2}=0.25mol\text{ }O_2=n$

Isolating V in the Ideal Gas Law:

$PV=nRT$

$V=\frac{nRT}{P}$

...substituting the known values, and simplifying...

$V=\frac{(0.025 mol \text{ }O_2)(0.0821\frac{L\cdot atm}{mol \cdot K} )(273.15K)}{(1atm)}$

$V=0.56L \text{ } O_2$

So, 0.80g of $O_2(g)$ would occupy 0.56L at STP.

5 0

2 years ago

Read 2 more answers

Write the equilibrium expression of each chemical equation. 2H2S(g) 2H2(g) + S2(g)

hodyreva [135]

Answer:

[H2]2[S2][H2S]2Kc=[H2]2[S2][H2S]2

Explanation:

2H2S(g)⇋2H2(g)+S2(g)2H2S(g)⇋2H2(g)+S2(g)

The equilibrium constant expression in terms of concentrations is:

Kc=[H2]2[S2][H2S]2Kc=[H2]2[S2][H2S]2.

6 0

3 years ago

Why k has more shielding effect than Na?

lara [203]

Explanation:

As the charge of all electrons are equal, the repulsive force exerted by each of them is also going to be equal. So, as K has more electrons repulsing its valence electron than Na, it has greater electron shielding.

8 0

3 years ago

Explain why chloro acetic acid strong and than acetic acid

Basile [38]

Chloroacetic acid is stronger than acetic acid because of the electron-withdrawing effect of chlorine. This effect is caused by the electronegativity.

7 0

4 years ago

Suppose the gas resulting from the sublimation of 1.00 g carbon dioxide is collected over water at 25.0◦c into a 1.00 l containe

jeyben [28]

Answer:

0.55 atm

Explanation:

First of all, we need to calculate the number of moles corresponding to 1.00 g of carbon dioxide. This is given by

$n=\frac{m}{M_m}$

where

m = 1.00 g is the mass of the gas

Mm = 44.0 g/mol is the molar mass of the gas

Substituting,

$n=\frac{1.00 g}{44.0 g/mol}=0.0227 mol$

Now we can find the pressure of the gas by using the ideal gas law:

$pV=nRT$

where

p is the gas pressure

V = 1.00 L is the volume

n = 0.0227 mol is the number of moles

R = 0.082 L/(atm K mol) is the gas constant

T = 25.0 C + 273 = 298 K is the temperature of the gas

Solving the formula for p, we find

$p=\frac{nRT}{V}=\frac{(0.0227 mol)(0.082 L/(atm K mol))(298 K)}{1.00 L}=0.55 atm$

8 0

4 years ago