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4 years ago

True or False: Biosafety cabinets, clean benches, and chemical fume hoods all offer the same protection.

Chemistry

1 answer:

Dmitry [639]4 years ago

3 0

Answer:

False

Explanation:

The bio safety cabinets are design to protect from pathogens, that is the main reason why they are close cabinets.

The clean benches, even it is used for work with biological samples, they are innocuous samples, that mean that can coexist with humans.

The chemical fume hoods, even they have similar shape than the previous ones, they are use mainly to work with chemical materials, to extract fumes as a result of the reaction.

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If 40 grams of NH3 are dissolved in 100 mL of water at 10 degrees Celsius, how many more grams of NH3 would I need to add to mak

Katen [24]

20 g is the answer to make it a saturated solution

6 0

3 years ago

The element antimony has two stable isotopes, antimony-121 with a mass of 120.90 amu and antimony-123 with a mass of 122.90 amu.

NARA [144]

Answer:

antimony-121 has the highest percent natural abundance

Explanation:

percent natural abundance;

121.76 = 120.90 x + 122.90 (1 - x)

121.76 = 120.90 x + 122.90 - 122.90x

121.76 = -2x + 122.90

121.76 - 122.90 = -2x

x= 121.76 - 122.90/ -2

x= 0.57

Where x and 1 - x refers to the relative abundance of each of the isotopes

Percent natural abundance of antimony-121 = 57 %

Percent natural abundance of antimony-123 = (1 - 0.57) = 43%

Let us remember that isotopy refers to a phenomenon in which atoms of the same element have the same atomic number but different mass numbers. This results from differences in the number of neutrons in atoms of the same element.

We can clearly see that antimony-121 has the highest percent natural abundance.

8 0

3 years ago

What is the mole fraction of potassium dichromate, K2Cr2O7, in a solution prepared from 24.42 g of potassium dichromate and 240.

Harrizon [31]

Answer:

$6.19\times 10^{-3}$ is the mole fraction of potassium dichromate.

Explanation:

Mass of potassium dichromate = 24.42 g

Moles of potassium dichromate = $n_1=\frac{24.42 g}{294.185 g/mol}=0.0830 mol$

Mass of water = 240.0 g

Moles of water = $n_2=\frac{240.0 g}{18.015 g/mol}=13.3222 mol$

Mole fraction is calculated by:

$\chi_1=\frac{n_1}{n_1+n_2}$

$\chi_1=\frac{0.0830 mol}{0.0830 mol+13.3222 mol}=0.00619=6.19\times 10^{-3}$

$6.19\times 10^{-3}$ is the mole fraction of potassium dichromate.

8 0

3 years ago

which of the following is not a metamorphic agent ? A. force of hurricane winds B. pressure of over head rocks C. Chemically act

Sloan [31]

Answer:A

Explanation:

4 0

3 years ago

In general, the rate of a reaction can be increased by

stiv31 [10]

Answer: 1. All of these

Explanation:

The rate of a reaction depends on following factors:

1. increasing the concentration of reactants: means there is more particles of reactants per unit volume.Thus more particles can collide and hence the rate of reaction increases.

2. increasing the temperature- the particles move faster and undergo more collision which leads to an increase in the rate of the reaction.

3.adding an appropriate catalyst: addition of catalyst lowers the activation energy and thus more reactants can cross the energy barrier. Thus it leads to formation of more products hence an increase in the reaction rate.

Thus the rate of a reaction can be increased by all of these.

7 0

3 years ago