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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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Which of the following is an adaptation that helps protect the animal?
saveliy_v [14]
C ( Porcupines use there’s sharp quills to defend themselves from larger predators!)
6 0
2 years ago
The chemical equation is Mg(s) + O2(g) → MgO(s)
vredina [299]

Answer:

The magnesium will burn until consumed entirely. There is much more oxygen available in the atmosphere than needed to consume the magnesium. Thus the magnesium is the limiting reactant because it determines the amount of product formed.

Explanation:

Mg produces less amount of MgO than O2; therefore Mg is the limiting reagent. O2 produces more amount of MgO than Mg; therefore O2 is the excess reagent.

4 0
3 years ago
The pH of a solution is measured eight times by one operator using the same instrument. She obtains the following data: 7.15, 7.
sergiy2304 [10]

Answer:

7.186

Explanation:

The mean is the average of some given data from a sample point.

To calculate the mean, we use the formula below:

             Mean = ∑fx/∑f

Where f = frequency

           x = sample data

   

From the given pH of the solutions, we can form a table:

      x                                     f                                          fx

    7.15                                  1                                         7.15

    7.16                                  1                                         7.16

    7.18                                  1                                         7.18

    7.19                                  1                                         7.19

    7.20                                 3                                        21.6

    7.21                                  1                                         7.21

Now ∑fx = 7.15 +7.16 +7.18 + 7.19 + 7.20 + 7.21 = 57.49

         ∑f = 1 + 1 + 1 + 1 + 3 + 1 = 8

The mean = \frac{57.49}{8} = 7.18625 = 7.186

3 0
3 years ago
The volume of oxygen, collected over water, is 185 mL at 25 degrees Celsius and 600 torr. calculate the dry volume of the oxygen
ivolga24 [154]

Answer:

0.1593 L.

Explanation:

  • We can use the general law of ideal gas: PV = nRT.

where, P is the pressure of the gas in atm.

V is the volume of the gas in L.

n is the no. of moles of the gas in mol.

R is the general gas constant,

T is the temperature of the gas in K.

  • If n and P are constant, and have two different values of V and T:

<em>P₁V₁T₂ = P₂V₂T₁</em>

<em></em>

P₁ = 600 torr/760 = 0.789 atm, V₁ = 185.0 mL = 0.185 L, T₁ = 25.0°C + 273 = 298.0 K.

P₂ (at STP) = 1.0 atm, V₂ = ??? L, T₂ (at STP = 0.0°C) = 0.0°C + 273 = 273.0 K.

<em>∴ V₂ = P₁V₁T₂/P₂T₁</em> = (0.789 atm)(0.185 mL)(298.0 K)/(1.0 atm)(273.0 K) = <em>0.1593 L.</em>

4 0
3 years ago
Bismuth oxide reacts with carbon to form bismuth metal: bi2o3(s) + 3c(s) → 2bi(s) + 3co(g) when 689 g of bi2o3 reacts with exces
ExtremeBDS [4]
Using the answer from the first part, we know that 2.957 moles of bismuth have formed. Moreover, the molar ratio between bismuth and carbon monoxide is:

2 : 3

Using the method of ratios,

2 : 3
2.957 : CO

CO = (3 * 2.957) / 2
CO = 4.4355

4.436 moles of carbon monoxide will be formed
8 0
3 years ago
Read 2 more answers
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