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BlackZzzverrR [31]
2 years ago
4

Too many objects inside a laboratory fume hood can disrupt the airflow and possibly compromise you safety. Which of the followin

g are considered best practices in the use of a laboratory fume hood?
a. Open the sash as much as possible
b. Work at least 25 cm inside the hood
c. Use fast, quick movements to limit your exposure
d. Place objects to one side—work on other side
e. Use a raised along the back of the hood
Chemistry
1 answer:
Alex787 [66]2 years ago
5 0

Answer:

a. Open the sash as much as possible

d. Place objects to one side—work on other side

Explanation:

Opening the sash as much as possible so that the harmful fumes goes outside through it and place objects to one side and work on other side at a certain distance from the chemical reaction. The fumes releases from a chemical reaction are harmful that can severely damaged the body of the researcher so these two methods can be used in order to reduce the damages.

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Nickel can be plated from aqueous solution according to the following half reaction. How long would it take (in min) to plate 29
andrey2020 [161]

Answer:

It take 3.5 *10² min

Explanation:

Step 1: Data given

Mass of the nickel = 29.6 grams

4.7A

Step 2: The balanced equation

Ni2+ (aq- +2e- → Ni(s)

Step 3: Calculate time

W = (ItA)/(n*F)

  ⇒ W = weight of plated metal in grams = 29.6

 ⇒ I = current in coulombs per second. = 4.7

 ⇒ t = time in seconds.

 ⇒ A = atomic weight of the metal in grams per mole. = 58.69

 ⇒ n = valence of dissolved metal in solution in equivalents per mole.  = 2

 ⇒ F = Faraday's constant in coulombs per equivalent. F = 96,485.309               coulombs/equivalent.

29.6 = (4.7 * t * 58.69)/(2*96485309)

t = 20707 seconds

t =345 minutes = 3.5 * 10² min

It take 3.5 *10² min

7 0
2 years ago
How much heat is required to raise the temperature of 670g of water from 25.7"C to 66,0°C? The specific heat
inna [77]

Answer:

Explanation:

q= mc theta

where,

Q = heat gained

m = mass of the substance = 670g

c = heat capacity of water= 4.1 J/g°C    

theta =Change in temperature=( 66-25.7)

Now put all the given values in the above formula, we get the amount of heat needed.

q= mctheta

q=670*4.1*(66-25.7)

  =670*4.1*40.3

=110704.1

8 0
2 years ago
You are presented with a mystery as part of your practical experiment. You have a solution of Pb(NO3)2 that has a worn label mak
Orlov [11]

Answer:

Minimum volume of H₂SO₄ required for H₂SO₄ to be in excess = 0.0556 mL

Explanation:

Pb(NO₃)₂ + H₂SO₄ -----> PbSO₄ + 2HNO₃

For this reaction, we know that the max concentration of Pb(NO₃) according to the bottle is 0.999M and to ensure the other reactant in the reaction is in excess, we'll do the calculation with a Pb(NO₃) that's a bit higher, that is, 1.0M.

Knowing that Concentration in mol/L = (number of moles)/(volume in L)

Number of moles of Pb(NO₃) added = concentration in mol/L × volume in L = 1 × 0.001 = 0.001 mole

According to the reaction,

1 mole of Pb(NO₃) reacts with 1 mole of H₂SO₄

0.001 mole of Pb(NO₃) will react with 0.001×1/1 mole of H₂SO₄

Therefore number of H₂SO₄ required for the reaction and for the H₂SO₄ to be in excess is 0.001 mole of H₂SO₄

So, the concentration of commercial H₂SO₄ is usually 18.0M, using this as the assumed value.

Volume of H₂SO₄ = (number of H₂SO₄ required for it to be in excess)/(concentration of H₂SO₄)

Volume of H₂SO₄ = 0.001/18 = 0.0000556 L = 0.0556 mL.

QED!!!

5 0
2 years ago
A student wants to draw a model of an atom. Which statement describes how to find the number of neutrons to include in the model
san4es73 [151]

c is the correct answer

4 0
2 years ago
An irregularly shaped solid which has a mass of 10.283g was placed in a graduated cylinder containing an inert liquid. The initi
Gwar [14]
Liquid  + Solid = 8.89 mL
V ( Solid ) = 8.89 mL - 6.26 mL = 2.63 mL
The density of the solid = m / V = 10.283 g / 2.63 mL =
= 3.9 g/mL = 3.9 g / cm³
3 0
2 years ago
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