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3 years ago

Why is very important to wait until the crucible is fully coleed to room temperature before weighting

1 answer:

3 0

If you do not wait until the crucible is at room temperature, its density will vary constantly until it reaches this temperature, since density is a property that varies with temperature. For the above reason, weighing a hot crucible will not allow the measurement of a constant weight on the balance, since the weight of the object will be constantly changing, which will not allow a constant reading.

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Calculate the number of molecules in a deep breath of air whose volume is 2.15 L at body temperature, 37 ∘C, and a pressure of 7

Zinaida [17]

PV = nRT
R = 0.0821 L * atm / mol * K
(ideal gas constant)

First, convert 735 torr to atm. Divide by 760.
(1 atm = 760 torr)

735 torr * 1 atm / 760 torr = 0.967 atm
Then, convert 37 C to Kelvin. Just add 273.
37 C = 310K

n = PV / RT
= (0.967)(2.07) / (0.0821)(310)
= 0.0786 mol

0.0786 mol * 6.02 * 10^23 molecules / 1 mol = 4.73 * 10^22 molecules

7 0

3 years ago

Read 2 more answers

If a piece of metal were to cut in half would the density change

nadezda [96]

Density depends on both the mass and the volume of an object. If you cut a bar of gold in half, you would have two bars with half the mass of the original bar. However, each bar would also have half the volume of the original bar. The density of gold does not change.

8 0

3 years ago

Read 2 more answers

27. The density of nickel is 8.91 g/cm3. How large a cube, in cm3, would contain 2.00 x 10^24 atoms of nickel? Use dimensional a

jok3333 [9.3K]

Answer : The volume of the cube is, $21.88cm^3$

Solution : Given,

Density of nickel = $8.91g/cm^3$

Number of nickel atoms = $2\times 10^{24}$

Molar mass of nickel = 58.7 g/mole

First we have to calculate the moles of nickel.

As, $6.022\times 10^{23}$ atoms form 1 mole of nickel

So, $2\times 10^{24}$ atoms form $\frac{2\times 10^{24}}{6.022\times 10^{23}}=3.321$ moles of nickel

The moles of nickel = 3.321 moles

Now we have to calculate the mass of nickel.

$\text{ Mass of Ni}=\text{ Moles of Ni}\times \text{ Molar mass of Ni}$

$\text{ Mass of Ni}=(3.321moles)\times (58.7g/mole)=194.94g$

The mass of nickel = 194.94 g

Now we have to calculate the volume of nickel.

$Density=\frac{Mass}{Volume}$

$8.91g/cm^3=\frac{194.94g}{Volume}$

$Volume=21.88cm^3$

Therefore, the volume of the cube is, $21.88cm^3$

4 0

3 years ago

What is the correct equilibrium constant expression for equation P2(g)

sertanlavr [38]

Answer:

k = [F2]² [PO]² / [P2] [F2O]²

Explanation:

In a chemical equilibrium, the equilibrium constant expression is written as the ratio between the molar concentration of the products over the molar concentration of the reactants. Each species powered to its reaction coefficient. For the equilibrium:

P2(g) + 2F2O(g) ⇄ 2PO(g) + 2F2(g)

The equilibrium constant, k, is:

k = [F2]² [PO]² / [P2] [F2O]²

6 0

3 years ago

How many isomers does propane have? 01 02 03 05

Irina18 [472]

Answer:

A.) 1

Explanation:

Propane only exists in one conformation. It does not have enough carbons to form branches, and there are only hydrogens attached to each carbon. Furthermore, there is no way to twist the carbon or change its orientation (ex. cis- and trans-) to result in a different structure of propane. There is no other way to represent the molecule without drawing a different molecule.

5 0

2 years ago