When preparing for work in the fume hood, be sure to gather all necessary tools, glassware, and chemicals _________ to minimize the number of times the hood sash is raised and lowered. Work as much as possible in the _________ of the work surface to keep the area tidy and promote air flow. If you need to step away from the experiment to obtain another item, _________ the sash during this time.

Answers

Answer 1

Answer:

In advance

middle

lower

Explanation:

These are the safety precautions needed when carrying out duties in the fume hood.

When planning and preparing to work in a fume hood (a locally designed area to reduce exposure to hazardous fumes). It is advisable to make all equipment readily available at your disposal in advance to reduce and minimize the raising and lowering of the hood sash at intervals.

It is also pertinent to understand that working in the middle of the work surface helps to promote the movement of air and keeps the area neat and tidy.

However, if any case where there is a need to get a new tool or equipment during the process of working in a fume hood, it is advisable to lower the sash at that point in time.


Related Questions

What is aspartame? EXPLAIN

Answers

Answer:

it's an artificial non-saccharide sweetener 200 times sweeter than sucrose, and is commonly used as a sugar substitute in foods and beverages. it's a methyl ester of the aspartic acid/phenylalanine dipeptide with the trade names NutraSweet, Equal, and Canderel

Explanation:

Answer:

Aspartame is some type of very sweet substance that is used as an artificial sweetener, and chiefly in low-calorie products. It is a derivative of aspartic acid and phenylalanine.

Explanation:

2. Each cart below is pushed across a room with the same amount of force. Which cart will result in the greatest change in speed?

A )A 15 kg cart being pushed with a 200 N force
B ) A25 kg box being pushed with a 200 N force
C )A 45 kg cart being pushed with a 200 N force
D )A 35 kg box being pushed with a 200 N force​

Answers

Answer: A 15 kg cart being pushed with a 200 N force.

Explanation:

The 15 kg cart is the lightest, so it has the least amount of friction on the ground.

The cart that will result in the greatest change in speed is the cart with a mass of 15 Kg

The correct answer to the question is Option (A) A 15 kg cart being pushed with a 200 N force

Acceleration is defined as the change in velocity of an object with time.

Acceleration is also related to force and mass according to the following equation:

Acceleration (a) = Force (F) / mass (m)

a = F / m

To answer the question given above, we shall determine the acceleration of the cart in each option.

For Option A:

Mass (m) = 15 Kg

Force (F) = 200 N

Acceleration (a) =?

a = F / m

a = 200 / 15

a = 13.33 m/s²

For Option B:

Mass (m) = 25 Kg

Force (F) = 200 N

Acceleration (a) =?

a = F / m

a = 200 / 25

a = 8 m/s²

For Option C:

Mass (m) = 45 Kg

Force (F) = 200 N

Acceleration (a) =?

a = F / m

a = 200 / 45

a = 4.44 m/s²

For Option D:

Mass (m) = 35 Kg

Force (F) = 200 N

Acceleration (a) =?

a = F / m

a = 200 / 35

a = 5.51 m/s²

From the illustrations made above, we can see that the cart with a mass of 15 Kg has the greatest acceleration (i.e change in speed)

Therefore, the correct answer to the question is Option (A) A 15 kg cart being pushed with a 200 N force

Learn more: https://brainly.com/question/25816322

Heat is most closely related to which kind of energy?

Answers

Answer:

radial energy because it's a heat energy!

Explanation:

There are more types but that's the closest in my opinion!!

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Thermal Energy

Explanation:

known as heat energy produced when a rise in temperature causes atoms and molecules to move faster and collide with each other.

Three resonance structures of the given anion are possible. One is given, but it is incomplete. Complete the given structure by adding nonbonding electrons and formal charges. Draw the two remaining resonance structures (in any order), including nonbonding electrons and formal charges. Omit curved arrows.

Answers

Answer:

Explanation:

The missing incomplete resonance structure is attached in the image below. From there, we can see the addition of the nonbonding electrons and its' formal charge which makes the resonance structure a complete resonance structure. The others two resonance structure that can be derived from the complete structure is also shown in the image. Out of these three structures, the structure that contributes most to the hybrid is the structure with the negative charge on the oxygen.

Gluons carry

a
the weak force
b
gravity
c
Bosons
d
the strong force
e
electromagnetic force

Answers

Answer:

the answer is d

hope this helpssss

1. How many molecular orbitals can be built from the valence shell orbitals in O2?

Answers

Answer:

Atomic oxygen has 6 valence electrons and 4 valence orbitals (2s, 2px, 2py, and 2pz). We can draw a Lewis structure of molecular oxygen with a double bond between the oxygen atoms and 2 non-bonding pairs of electrons on each atom.

Many compressed gases come in large, heavy metal cylinders that are so bevy that they need a special cart to move them around. An 80.0-L tank of nitrogen gas pressurized to 172 arm atm is left in the sun and heats from its normal temperature of 20.0 degrees Celsius to 140.0 degrees Celsius. Determine (a) the final pressure inside the tank and (b) the work, heat, and delta U of the process. assume that behavior is ideal and the heat capacity of diatomic nitrogen is 21.0 j/molk.

Answers

Answer:

a) final pressure inside the tank is 242.4 atm

b)

Work = 0

heat q = 1440.85 kJ

DU = 1440.85 kJ

Explanation:

Given that;

Pressure P1 = 172 atm

Volume V = 80 L

Temperature T1 = 20°C = ( 273.15 + 20) = 293.15 K

Temperature T2 = 140°C = ( 273.15 + 140) = 413.15 K

we know that, gas constant R = 0.0821 atm.L/mol.K

from the Ideal Gas equation;

pV = nRT1

n = pV/RT1

we substitute

n = (172 × 80) / (0.0821 × 293.15)

n = 13760 / 24.067615  

n = 571.72 moles

now

P2 = nRT2/V2

P2 = (571.72 × 0.0821 × 413.15) / 80

P2 = 19392.5222 / 80

P2 = 242.4 atm

Therefore, final pressure inside the tank is 242.4 atm

b)

we know

w = -∫[tex]P_{ext}[/tex] dv

now, since there is no change in volume; dv = 0

so

w = 0

Work = 0

dU = cVDT

Cv = nCr,m

Cv = 571.72 ×  21.0

Cv = 12007.12 J/k

DU = CvΔT

DU = 12007.12 × (413.15 - 293.15)

DU = 1440854.4 J

DU = 1440.85 kJ

DU = q + w

1440.85 = q + 0

heat q = 1440.85 kJ

calculate the number of atoms in 0.25 mole of uranium.

Answers

Answer: 0.25 mol × (6.02214 × 1023 /mol) = 1.5 × 10

Explanation: Hope that helps

How many moles of water can be formed from 0.57 moles of hydrogen gas?

Answers

Answer:

0.57 water

Explanation:

To solve this problem, we need to write the reaction expression first.

The reactants are oxygen gas and hydrogen gas.

They react to give a product of water

       2H₂    +    O₂   →   2 H₂O  

Given that;

Number of moles of hydrogen gas = 0.57moles

From the balanced reaction expression;

       2 moles of hydrogen gas produces 2 moles of water

   So;

    0.57mole of hydrogen gas will also produce 0.57 water

Please help with whatever this is and go in number order

Answers

1.a- sodium(Na) b-nickel(Ni) c-iron (Fe)

Given the equation:

4Al2O3 + 9Fe --> 3Fe3O4 + 8Al

If 27.5 g of Al2O3 reacted with 8.4 g of Fe, how many of Fe 3O4 are formed?

a) Calculate the limiting reactant


b) Calculate the number of grams of Al produced.


c) Calculate the number of grams of Fe3O4 produced.


d) Calculate the percent yield if 10g of Fe O4 were obtained?

Answers

Answer: a)  [tex]Fe[/tex] is the limiting reagent

b) 3.59 g

c) 11.6g

Explanation:

[tex]4Al_2O_3+9Fe\rightarrow 3Fe_3O_4+8Al[/tex]  

To calculate the moles :

   

[tex]\text{Moles of} Al_2O_3=\frac{27.5g}{102g/mol}=0.27moles[/tex]

[tex]\text{Moles of} Fe=\frac{8.4g}{56g/mol}=0.15moles[/tex]

According to stoichiometry :

a) 9 moles of [tex]Fe[/tex]  require= 4 moles of [tex]Al_2O_3[/tex]

Thus 0.15 moles of [tex]Fe[/tex] will require=[tex]\frac{4}{9}\times 0.15=0.067moles[/tex]  of [tex]Al[/tex]

Thus [tex]Fe[/tex] is the limiting reagent as it limits the formation of product and [tex]Al[/tex] is the excess reagent.

b) As 9 moles of [tex]Fe[/tex] give = 8 moles of [tex]Al[/tex]

Thus 0.15 moles of [tex]Fe[/tex] give =[tex]\frac{8}{9}\times 0.15=0.133moles[/tex]  of [tex]Al[/tex]

Mass of [tex]Al=moles\times {\text {Molar mass}}=0.133moles\times 27g/mol=3.59g[/tex]

c) As 9 moles of [tex]Fe[/tex] give = 3 moles of [tex]Fe_3O_4[/tex]

Thus 0.15 moles of [tex]Fe[/tex] give =[tex]\frac{3}{9}\times 0.15=0.05moles[/tex]  of [tex]Fe_3O_4[/tex]

Mass of [tex]Fe_3O_4=moles\times {\text {Molar mass}}=0..05moles\times 231.5g/mol=11.6g[/tex]

What are the correct products for the following reaction? ---->

K2SO4 + MgF2 ---->
Question 3 options:


2KF + MgSO4


F2SO4 + K2Mg


No reaction will occur


K2SO4 + F2Mg

Answers

Answer:

2KF+MgSO4

Explanation:

The correct product of the reaction above is 2KF + MgSO4.

What is a chemical reaction?

A chemical reaction is a reaction in which the reactants or reacting substances react or combine together to produce the products.

Therefore, The correct product of the reaction above is 2KF + MgSO4.

Learn more about chemical reactions below.

https://brainly.com/question/11231920

#SPJ2

15.0 g of Fe and 25.0 g of sand are added to 250.0 g of water. a. Determine the percent mass of Fe, sand, and water in the mixture. b. Create a flow chart illustrating how you could separate each of the mixture’s components. c. Explain which step of the separation is likely to have the highest amount of error.

Answers

Answer:

A. percentage mass of iron = 5.17%

percentage mass of sand  = 8.62%

percentage mass of water = 86.205%

B. (Iron + sand + water) -------> ( iron + sand) ------> sand

C. The step of separation of iron and sand

Explanation:

A. Percentage mass of the mixtures:

Total mass of mixture = (15.0 + 25.0 + 250.0) g =290.0 g

percentage mass of iron = 15/290 * 100% = 5.17%

percentage mass of sand = 25/290 * 100% = 8.62%

percentage mass of water = 250/290 * 100% = 86.205%

B. Flow chart of separation procedure

(Iron + sand + water) -------> separation by filtration using filter paper and funnel to remove water --------> ( iron + sand) -----------> separation using magnet to remove iron ------> sand

C. The step of separation of iron and sand by magnetization of iron will have the highest amount of error because during the process, some iron particles may not readily be attracted to the magnet as they may have become interlaced in-between sand grains. Also, some sand particle may also be attracted to the magnet as they are are borne on iron particles.

An ionic compound has a generic formula of QR2.

Which elements could the Q and R represent?

Once you choose an answer, check it by plugging those elements into the QR2 formula to see if it looks right.

Q= Sodium R= Oxygen

Q= Magnesium R= Chlorine

Q= Oxygen R= Sodium

Q= Chlorine R= Magnesium

Answers

Answer:

Q= Magnesium R= Chlorine

Explanation:

The element Q should be magnesium and R is chlorine.

An ionic compound is a compound that is formed by the combination of a metal and non-metal. Such bonds forms when there is a transfer of electrons from the metals to the non-metals. This leaves a net positive charge on the metal and a negative charge on the non-metal.

The electrostatic attraction leads to the formation of the bond.

 To solve this problem, the hypothetical compound is QR₂

       Mg                        Cl

     2 8 2                    2 8 7

So, Mg transfers 2 electrons to two atoms of chlorine.

 This leads to the formation of the compound MgCl₂

Why do organisms eat food? Be sure to explain your answer. ​

Answers

Answer:

Organisms need to take food to get energy and perform life processes. A living organism undergoes many life processes like nutrition, respiration, digestion, transportation, excretion, circulation of blood, and reproduction. To perform all these life processes the organism needs energy and nutrients.

Explanation:

nnastarannnn his idea

What is the value of 4.698 after rounding it down to 3 significant figures?

Answers

The value of 4.698 rounded down to 3 S.F is 4.70

Dale is speaking to a group of students about the importance of extracurricular activities. He provides specific scenarios to show the audience how the information presented will affected them directly. Dale is fulfilling which goal of informational speaking?
to enhance understanding

to be heard

to maintain interest

to be remembered

Answers

To maintain interest

Answer the given question: use Chapter 1 of notebook
How many formula units are there in 3.20x 102 moles of LICI? (2pts.)
Conversion factor: 1 mole LICI=
_formula of LICI
Students, draw anywhere on this slide!

Answers

Answer:

1.93 x 10²⁶ formula units

Explanation:

Given parameters:

Number of moles of LiCl  = 3.2 x 10² moles  = 320moles

Unknown:

Number of formula units in this compound  = ?

Solution:

The mole is used a reference to determine the number of substances matters contain.

 A mole contains the Avogadro's number of particles.

 So;

       1 mole of a substance contains 6.02 x 10²³ formula units;

320 moles of LiCl will contain 320 x  6.02 x 10²³  = 1.93 x 10²⁶ formula units

Conduction happens as energy flows from a warmer object to a cooler object. Which of the following is evidence of conduction?

Answers

Explanation:

Conduction is a form of heat transfer between one body and another. It usually occurs when a warmer object is in contact with a cooler one. Heat generally flows from a region of high temperature to a place at a lower temperature.

Conduction is very pronounced in solid bodies. The heat transfer causes a net transfer of the average kinetic energy of one body to the other. Some examples are: heating of iron by a hotter metallic body, the pot hand getting hotter as cooking continues, cooling of ice by touching it.

What is the maximum mass of ammonia (NH3) that can be produced from the synthesis reaction of 781 g of nitrogen and 656 g hydrogen?

HINT: You will need to write a balanced chemical equation and perform 2 calculations before you can determine the answers.

Answers

N2(g)+3H2 >>>>>2NH3(g)

the mole ratio between N2, H2 and NH3. It is 1 : 3 : 2

mole N2 present
moles H2 present = 25.0 g H2 x 1 mole H2/2 g = 12.5 moles H2 present
Based on mole ratio, N2 is limiting in this situation because there is more than enough H2 but not enough N2.

moles NH3 that can be produced = 1 mole N2 x 2 moles NH3/mole N2 = 2 moles NH3 can be produced
grams of NH3 that can be produced = 2 moles NH3 x 17 g/mole = 34 grams of NH3 can be produced

What is the difference between stored energy and usable energy

Answers

answer:

In biology, the energy that is stored in the bonds between compounds is termed as the chemical energy. This chemical energy is released and converted into different forms according to the functions of the body.

Potential energy can be described as the energy that is stored in an object. In physics, the energy that an object possesses while at rest is termed as the potential energy.

The energy that can be used during work is termed as the kinetic energy. In physics, kinetic energy can be described as the energy that an object possesses while in motion.

-- please mark the brainliest and click the thanks button if correct :)

Answer: The stored energy is termed as potential energy while the working energy is termed as kinetic energy. The electricity used in our homes is also a form of energy because it is a form of usable power. The places from which the different energies are obtained are known as energy sources.

How many cells are a result of Meiosis?

Answers

Answer:

2

Explanation:

Cells divide and reproduce in two ways, mitosis and meiosis. Mitosis results in two identical daughter cells, whereas meiosis results in four sex cells.

In Part III, the methyl orange indicator is used to monitor the equilibrium shifts of the acetic acid/acetate ion system. The methyl orange equilibrium established with water is Hmo(aq)(orange-red) H2O(l) H3O (aq) mo-(aq)(yellow). You compared the color of the solutions in three test tubes that initially contained 3 mL of 0.1 M acetic acid and a few drops of methyl orange indicator. In the first test tube, you added 1.0 M NaC2H3O2 drop wise. What color change was observed and what did this color change indicate about the shift in the methyl orange equilibrium

Answers

Answer:

See explanation

Explanation:

Let us look at the situation closely, the undissociated Hmo is red in colour while the mo^- is yellow in colour.

This means that an acidic solution will appear red while a basic solution will appear yellow in colour.

NaC2H3O2 is a basic salt. When it is introduced, the acetate ion pulls a proton from water forming  CH3COOH. CH3COOH is a weak acid and largely does not dissociate, it means that the undissociated acid remains in the solution leaving only the OH^- ions floating around thereby making the solution basic.

The colour of the system now changes to yellow.

Consider the equilibrium;

CH3COO^-(aq) + H2O(l) ------> CH3COOH(aq) + OH^-

Addition of NaC2H3O2  causes the equilibrium of this system to shift to the right.

The methyl orange water equilibrium also shifts towards the position where more mo^-(yellow) is produced.

Please help me thanks so much!?!?!?

Answers

Answer:

Lighting the stove and cooking the meat are both chemical changes.

Explanation:

Both fire and cooking are chemical changes.

Answer:

the second one

Explanation:

which section from the article most emphasizes the role of technological development in the discovery of cells

Answers

Answer:

B. The microscope paved the way

Explanation:

This section from the article, "History of the Cell: Discovering the Cell", that emphasizes the role of technological development in the discovery of cells, is the subheading, "The microscope paved the way". In this subheading, the author narrated how Robert Hooke improved the existing microscope, and was able to discover the cell through it.

Further improvement of the simple microscope by Antonie van Leeuwenhoek led to the discovery of bacteria and protozoa.

How many molecules are there in 42gms of Na?

Answers

there should be 1.8 mol Na

Which of the following choices is not evidence supporting the theory of plate tectonics?

Answers

Answer:

B

Explanation:

what divided by 700000 equals 4

Answers

I think it’s 280000

Sally does the work in 2.3 hours and Pete does 2.5

Answers

pete because 2.5 x 2.3 is faster
I agree with the other comment

What is the amount of heat required to complete MELT a 200 gram sample of H2O(s)

Answers

Answer:

66800 J

Explanation:

From the question given above, the following data were obtained:

Mass (m) = 200 g

Heat (Q) required =?

The heat required to melt the 200 g sample of water can be obtained as:

Mass (m) = 200 g

Latent heat of water (L) = 334 J/g

Heat (Q) required =?

Q = mL

Q = 200 × 334

Q = 66800 J

Thus, 66800 J of heat energy is required to melt the sample of water.

Answer:

66800 J

Explanation:

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