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3 years ago

How much lead (pb) is in 5.07 × 1012 atoms of lead? answer in units of mol?

Chemistry

1 answer:

Butoxors [25]3 years ago

4 0

Answer:

2.49⋅10−12moles Pb

Explanation:

Before doing any calculations, it's worth noting that atoms do not contain moles, it's the other way around.

A mole is simply a collection of atoms. More specifically, you need to have exactly 6.022⋅1023 atoms of an element in order to have one mole of that element - this is known as Avogadro's number.

In your case, you must determine how many moles of lead would contain 1.50⋅1012atoms of lead.

Well, if you know that one mole of lead must contain 6.022⋅1023 atoms of lead, it follows that you get 1.50⋅1012 atoms of lead in

1.50⋅1012atoms of Pb⋅1 mole Pb6.022⋅1023atoms of Pb=2.49⋅10−12moles Pb

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How many molecules are there in 5H20? A.5 B.7 C.10 D.11

Ad libitum [116K]

Answer:

the answers B which is 7

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3 years ago

Why do we need to use moles when we try to determine amounts of reactants and products in a reaction?.

ICE Princess25 [194]

$\huge\fbox{Answer ☘}$

Chemists use the mole unit to represent 6.022 × 10 23 things, whether the things are atoms of elements or molecules of compounds. This number, called Avogadro's number, is important because this number of atoms or molecules has the same mass in grams as one atom or molecule has in atomic mass units.

hope helpful~

8 0

3 years ago

Starting with 2.50 mol of N2 gas (assumed to be ideal) in a cylinder at 1.00 atm and 20.0C, a chemist first heats the gas at con

arsen [322]

Answer:

a) $T_b=590.775k$

b) $W_t=1.08*10^4J$

d) $Q=3.778*10^4J$

d) $\triangle V=4.058*10^4J$

Explanation:

From the question we are told that:

Moles of N2 $n=2.50$

Atmospheric pressure $P=100atm$

Temperature $t=20 \textdegree C$

$t = 20+273$

$t = 293k$

Initial heat $Q=1.36 * 10^4 J$

Generally the equation for change in temperature is mathematically given by

$\triangle T=\frac{Q}{N*C_v}$

Where

$C_v=Heat\ Capacity \approx 20.76 J/mol/K$

$T_b-T_a=\frac{1.36 * 10^4 J}{2.5*20.76 }$

$T_b-293k=297.775$

$T_b=590.775k$

Generally the equation for ideal gas is mathematically given by

$PV=nRT$

For v double

$T_c=2*590.775k$

$T_c=1181.55k$

Therefore

$PV=Wbc$

$Wbc=(2.20)(8.314)(1181_590.778)$

$Wbc=10805.7J$

Total Work-done $W_t$

$W_t=Wab+Wbc$

$W_t=0+1.08*10^4$

$W_t=1.08*10^4J$

Generally the equation for amount of heat added is mathematically given by

$Q=nC_p\triangle T$

$Q=2.20*2907*(1181.55-590.775)\\$

$Q=3.778*10^4J$

Generally the equation for change in internal energy of the gas is mathematically given by

$\triangle V=nC_v \triangle T$

$\triangle V=2.20*20.76*(1181.55-293)k$

$\triangle V=4.058*10^4J$

3 0

3 years ago

What is the wavelength, in nm, of the light photon emitted by a hydrogen atom when an electron goes from n

xxMikexx [17]

Answer:

Hence, the wavelength of the photon associated is 1282 nm.

Explanation:

8 0

3 years ago

15.0 mL of an unknown clear liquid is added to a 50 mL graduated cylinder. The mass of the liquid is determined to be 12.7 grams

sveticcg [70]

Answer:

$\boxed {\tt A. \ d=0.85 \ g/mL}$

Explanation:

Density is found by dividing the mass by the volume.

$d=\frac{m}{v}$

The mass of the liquid is 12.7 grams.

We know that 15 mL of this liquid was added to a 50 mL graduated cylinder. Therefore, the volume is 15 mL. The 50 mL is not relevant, it only tells us about the graduated cylinder.

$m= 12.7 \ g\\v= 15 \ mL$

Substitute the values into the formula.

$d=\frac{12.7 \ g}{ 15 mL}$

Divide.

$d=0.846666667 \ g/mL$

Round to the nearest hundredth. The 6 in the tenth place tells us to round the 4 to a 5.

$d \approx 0.85 \ g/mL$

The density of the liquid is about 0.85 grams per milliliter and choice A is correct.

4 0

3 years ago