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konstantin123 [22]
3 years ago
11

Eva is performing an experiment to determine which type of disinfectant kills the most bacteria. She has six plates of the same

kind and amount of bacteria. She adds one of five different kinds of disinfectant to each plate and leaves one plate without any disinfectant as a control.
What role does the independent variable play in this experiment
A.
The type of disinfectant determines the amount of bacteria killed.
B.
The amount of bacteria killed determines the type of bacteria used.
C.
The type of disinfectant used determines the type of bacteria used.
D.
The amount of bacteria killed determines the type of disinfectant used.
Chemistry
2 answers:
Soloha48 [4]3 years ago
6 0

A is the one so she could spot the differnece with natural and the unnatrual decline

Flura [38]3 years ago
5 0

Answer:

A

Explanation:

I did it just now

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Consider the reaction. Upper H subscript 2 upper o (g) plus upper C l subscript 2 upper O (g) double-headed arrow 2 upper H uppe
dedylja [7]

Answer:

Equilibrium constant for the reaction is 0.0892

Explanation:

This is the reaction of equilibrium

         H₂O      +     Cl₂O     ⇄    2HClO

Eq   0.077M       0.077M           0.023M

Let's make the expression for Kc

Kc = [HClO]² / [Cl₂O] . [H₂O]

Kc= 0.023² / 0.077 . 0.077 = 0.0892

5 0
3 years ago
Read 2 more answers
A non-mechanical, rigid, and fully insulated mixing tank is used to combine two inflows to produce wet steam. One inflow consist
Bogdan [553]

Explanation:

As it is given that stream A is super heated. From stream tables, we get that specific enthalpy, (h_{A}) is 3054.29 kJ/kg.

For stream B, it is saturated water at 25 degree celsius. It's h_{B} is 2546.54 kJ/kg.

Stream C, data will be as follows.

                P = 200 kPa,         \chi = 0.9

So, h_{c} = h_{f} + \chi \times h_{fg}  

        = 504.47 + 0.9 \times 2201.7

        = 2486 kJ/kg

Now, energy balance formula will be as follows.

            m_{A}h_{A} + m_{B}h_{B} = (m_{A} + m_{B})h_{c}

              3 \times 3054.29 + m_{B} \times 2546.54 = (3 + m_{B}) \times 2486

             m_{B} = 28.16 kg/s

Hence, inflow of saturated liquid is 28.16 kg/s. According to steam table, temperature of wet steam is 120.23^{o}C

Mass flow rate of out flow is 31.16 kg/s.

7 0
4 years ago
How many milliliters of a 1:2000 drug "i" solution and a 7% drug "i" solution mixed would make 120ml of a 3.5% solution of drug
yanalaym [24]

To solve this problem, let us say that:

x = volume of 1:2000 drug "i" solution

y = volume of 7% drug "i" solution

Assuming volume additive, then this forms:

x + y = 120 mL

<span>x = 120 – y                    ---> 1</span>

 

1:2000 also refers to 0.0005 concentrations and 7% also refers to 0.07 concentrations. By doing a component balance:

0.0005 x + 0.07 y = 0.035 (120 mL)

0.0005 x + 0.07 y = 4.2

Substituting equation 1 into this derived equation to get an equation in terms of y:

0.0005 (120 – y) + 0.07 y = 4.2

0.06 – 0.0005 y + 0.07 y = 4.2

0.0695 y = 4.14

y = 59.568 mL = 59.57 mL

 

From equation 1, x would be:

x = 120 - 59.57

x = 60.43 mL

 

Answers:

59.57 mL of 1:2000 drug "i" solution

60.43 mL <span>of 7% drug "i" solution</span>

3 0
3 years ago
Which of the compounds found in wood are difficult to degrade (or break apart)? (select all that apply.)?
Lera25 [3.4K]

There are four major components found in wood, and these are:

cellulose

lignin

starch

protein

 

Among the four, I believe that cellulose and lignin are the most difficult to degrade because they contain large amount of cross-linked heavy hydrocarbons.

 

Answer:

cellulose

lignin

3 0
3 years ago
A student is examining a bacterium under the microscope. The E. coli bacterial cell has a mass of m = 1.80 fg (where a femtogram
egoroff_w [7]

Answer:

Δx ≥  1.22 *10^-10m

Explanation:

<u>Step 1:</u> Data given

The E. coli bacterial cell has a mass of 1.80 fg ( = 1.80 * 10^-15 grams = 1.80 * 10^-18 kg)

Velocity of v = 8.00 μm/s (= 8.00 * 10^-6 m/s)

Uncertainty in the velocity = 3.00 %

E. coli bacterial cells are around 1 μm = 10^−6 m in length

<u>Step 2:</u> Calculate uncertainty in velocity

Δv = 0.03 * 8*10^-6 m/s =2.4 * 10^-7 m/s

<u>Step 3:</u> Calculate the uncertainty of the position of the bacterium

According to Heisenberg uncertainty principle,

Δx *Δp ≥ h/4π

Δx *mΔv ≥ h/4π

with Δx = TO BE DETERMINED

with m = 1.8 *10^-18 kg

with Δv = 2.4*10^-7

with h = constant of planck = 6.626 *10^-34

Δx ≥  6.626*10^-34 / (4π*(1.8*10^-18)(2.4*10^-7))

Δx ≥  1.22 *10^-10m

6 0
3 years ago
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