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2 years ago

Why do we need to clamp the rubber tube when we are transferring the flask from the boiling water to the cool water

1 answer:

8 0

<u>The flask assembly will heat up in hot water, pressure will build up inside the flask and it could </u><u>explode.</u>

The fingertip is kept in place throughout the transfer to prevent the seepage of the trapped air from the flask.
Inside the tank, the flask is constantly upside down. The flask can be tipped at an angle to allow the air to escape.
The entire contents of the pint will erupt out if only the bottom of the container is heated.
Rubber stoppers are ideal for plugging joints or holes in laboratory glassware and creating a liquid-tight seal.

What is the proper method for inserting glass tubing into a rubber stopper?

Lubricate the end of the glass tubing with a few drops of water, washing-up liquid, glycerol, or vegetable oil.
Hold the glass tubing close to where it enters the hole in the rubber stopper.
Ease the tubing into the hole with a gentle twisting motion.

Learn more about rubber stopper

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PLEASE, I REALLY NEED HELP!!!!

FrozenT [24]

1. The metamorphic rocks are produced when the parent or the pre-existing rocks (whether sedimentary, igneous, or even metamorphic) are changed by pressure, heat, and the chemical activity of the fluids.

When the prime changing factor is heat, generally due to direct contact, it may go through fundamental modification in recrystallization and texture is known as contact metamorphism. While regional metamorphism takes place when the minerals and texture of the rock are modified by pressure and heat.

7 0

3 years ago

A volume of 129 mL of hydrogen is collected over water. The water level in the collecting vessel is the same as the outside leve

mixas84 [53]

Explanation:

As it is given that water level is same as outside which means that theoretically, P = 756.0 torr.

So, using ideal gas equation we will calculate the number of moles as follows.

PV = nRT

or, n = $\frac{PV}{RT}$

= $\frac{\frac{756}{760}atm \times 0.129 L}{0.0821 Latm/mol K \times 298 K}$

= 0.0052 mol

Also, No. of moles = $\frac{mass}{\text{molar mass}}$

0.0052 mol = $\frac{mass}{2 g/mol}$

mass = 0.0104 g

As some of the water over which the hydrogen gas has been collected is present in the form of water vapor. Therefore, at $25^{o}C$

$P_{\text{water vapor}}$ = 24 mm Hg

= $\frac{24}{760}$ atm

= 0.03158 atm

Now, P = $\frac{756}{760} - 0.03158$

= 0.963 atm

Hence, n = $\frac{0.963 atm \times 0.129 L}{0.0821 L atm/mol K \times 298 K}$

= 0.0056 mol

So, mass of $H_{2}$ = 0.0056 mol × 2

= 0.01013 g (actual yield)

Therefore, calculate the percentage yield as follows.

Percent yield = $\frac{\text{Actual yield}}{\text{Theoretical yield}} \times 100$

= $\frac{0.01013 g}{0.0104 g} \times 100$

= 97.49%

Thus, we can conclude that the percent yield of hydrogen for the given reaction is 97.49%.

3 0

3 years ago

Energy in an ecosystem flow from consumers to producers.True of False

Alenkinab [10]

False - A producer always provides food for the consumer.

6 0

3 years ago

Read 2 more answers

What are deltaTb and deltaTf for an aqueous solution that is 1.5g nacl in 0.250kg h2o? Given Kb=0.51 C/m and kr=1.86 C/m

bulgar [2K]

Answer:

$T_f$ for given question is 2.79 and $T_b$ is 0.52

$\Delta T_b = I \times K_b \times m$ {i- vant hoff’s constant ; Kb- constant ; m molarity }

M = no. of moles of the solute present in one kg of solution

Let the weight of amount of solute be “w” and its molecular mass be “M”

Let the mass of the solvent in the given question be “x”

$\Delta T_b = I \times K_b \times (w/M)/ x$

$\Delta T_b = I \times K_b \times w/Mx$

$\Delta T_b = 1 \times 0.51 \times1.5/(0.250 \times 58.44) = 0.052$

$\Delta T_f = M \times K_f = 1.86 \times 1.5 = 2.79$

4 0

3 years ago

To what volume would you need to dilute 200 mL of a 5.85M solution of Ca(OH)2 to make it a 1.95M solution?

Blizzard [7]

Answer: 600 mL

Explanation:

Given that;

M₁ = 5.85 m

M₂ = 1.95 m

V₁ = 200 mL

V₂ = ?

Now from the dilution law;

M₁V₁ = M₂V₂

so we substitute

5.85 × 200 = 1.95 × V₂

1170 = 1.95V₂

V₂ = 1170 / 1.95

V₂ = 600 mL

Therefore final volume is 600 mL

8 0

3 years ago