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masya89 [10]
3 years ago
9

Which of the following is the most important, when working in the science laboratory?

Chemistry
1 answer:
Amanda [17]3 years ago
8 0
Safety is correct your welcome
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a laboratory procedure calls for making 510.0 mL of a 1.6 M KNO3 solution. How much KNO3 in grams is needed
barxatty [35]

Answer:

82.416 g of KNO ₃  is needed to produce 510.0 mL of a 1.6 M KNO ₃ solution.

Explanation:

Since molarity is the number of moles of solute that are dissolved in a given volume, calculated by dividing the moles of solute by the volume of the solution, the following rule of three can be applied: if in 1 L (1,000 mL) of KNO₃ there are 1.6 moles of the compound present, in 510 mL how many moles will there be?

moles=\frac{510 mL*1.6 moles}{1000 mL}

moles= 0.816

Being the molar mass of the elements:

  • K: 39 g/mole
  • N: 14 g/mole
  • O: 16 g/mole

So the molar mass of the compound KNO₃ is:

KNO₃= 39 g/mole + 14 g/mole + 3*16 g/mole= 101 g/mole

Now I can apply the following rule of three: if in 1 mole of KNO₃ there are 101 g, in 0.816 moles how much mass is there?

mass=\frac{0.816 moles*101 grams}{1 mole}

mass= 82.416 grams

<u><em>82.416 g of KNO ₃  is needed to produce 510.0 mL of a 1.6 M KNO ₃ solution.</em></u>

4 0
2 years ago
On a summer day early in the moming, a balloon is filled with helium when the temperature
MAXImum [283]

Based on the data provided;

  • number of moles of helium gas is 1.25 moles
  • pressure at peak temperature is 259.3 kPa
  • internal pressure is above 256 kPa, therefore, the balloon will burst.
  • pressure should be reduced to a value less than 256 kPa by reducing the temperature

<h3>What is the ideal has equation?</h3>

The ideal gas equation relatesthe pressure, volume, moles and temperature of a gas.

The moles of helium gas is calculated using the Ideal gas equation:

  • PV = nRT

n is the number of moles of gas

R is molar gas constant = 8.314 L⋅kPa/Kmol

P is pressure = 239 kPa

T is temperature = 21°C = 294 K

V is volume = 12.8 L

Therefore;

n = PV/RT

n = 239 × 12.8 / 8.314 × 294

n = 1.25 moles

The number of moles of helium gas is 1.25 moles

At peak temperature, T = 46°C = 319 K

Using P1/T1 = P2/T2

P2 = P1T2/T1

P2 = 239 × 319/294

P2 = 259.3 kPa

The pressure at peak temperature is 259.3 kPa

At 42°C, T = 315 K

Using P1/T1 = P2/T2

P2 = P1T2/T1

P2 = 239 × 315/294

P2 = 256.07 kPa

Since the internal pressure is above 256 kPa, the balloon will burst.

The pressure should be reduced to a value less than 256 kPa by reducing the temperature.

Learn more about gas ideal gas equation at: brainly.com/question/12873752

6 0
2 years ago
How does energy transfer from the sun to earth and the atmosphere
kumpel [21]

through conduction, radiation, and convection.

4 0
2 years ago
Describe the method of steel manufacture used when removes the impurities carbon, phosphorus and sulfur​
melisa1 [442]

Explanation:

Steelmaking is the process of producing steel from iron ore and/or scrap. In steelmaking, impurities such as nitrogen, silicon, phosphorus, sulfur and excess carbon (most important impurity) are removed from the sourced iron, and alloying elements such as manganese, nickel, chromium, carbon and vanadium are added to produce different grades of steel.

PLEASE THANK, RATE AND FOLLOW ME

HOPE IT HELPS YOU

6 0
3 years ago
Both 1,2−dihydronaphthalene and 1,4−dihydronaphthalene may be selectively hydrogenated to 1,2,3,4−tetrahydronaphthalene. One of
pochemuha

Answer:

1,4-dihydro = 113 kJ·mol⁻¹

1,2-dihydro = 101 kJ·mol⁻¹

Explanation:

In 1,4-dihydronaphthalene, the 2,3-double bond is isolated from the benzene ring.

In 1,2-dihydronaphthalene, the 3,4-double bond is conjugated with the benzene ring.

Thus, 1,2-dihydronaphthalene is partially stabilized by resonance interactions between the ring and the double bond (think, styrene).

1,2-Dihydronaphthalene is at a lower energy level because of this stabilization.

The heat of hydrogenation of 1,2-dihydronaphthalene is therefore less than that of the 1,4-isomer when each is hydrogenated to the common product, 1,2,3,4-tetrahydronaphthalene.

8 0
3 years ago
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