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Oduvanchick [21]
2 years ago
12

For her science project, Paula wants to determine if the growth of bacteria in standing rainwater changes over time. She collect

s rainwater and distributes it evenly in 6 jars and places them all indoors in a spot that does not receive a lot of sunlight to limit evaporation. Using a bacteria testing kit, she measures the bacteria in the water in the first jar on the 5th day, second jar on the 7th day, third jar on the 9th day, fourth jar on the 14th day, fifth jar on the 20th day, and sixth jar on the 24th day. What is the independent or manipulated variable in Paula's experiment?
Chemistry
1 answer:
tamaranim1 [39]2 years ago
8 0

Answer:

The correct answer is - the number of days the rainwater stands in the jars.

Explanation:

The independent variable or the manipulating variable is a variable in a research or study is the variable which affects the dependent variable or the variable that is going to measure in the study.

In the study, variables that recieves the treatment and changed in every subject are independent variables and in this study number of days the rainwater standing in various jars that might affect the growth of the bacteria in rainwater.

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What implications need to be considered when creating environmental policies?
Igoryamba

Answer:

How will it affect the environment? Is its benefit worth the cost?

Explanation:

when creating environmental policies you should always look into if it is worth it or not and how it will affect the environment  

4 0
2 years ago
Read 2 more answers
Determine the mass of 5.2 x 10 power of 21 molecules of propanol C3H7OH(l), on grams.
Alja [10]

n(\text{C}_3\text{H}_7\text{OH}) = N(\text{C}_3\text{H}_7\text{OH}) / N_A\\ \phantom{n(\text{C}_3\text{H}_7\text{OH})} = 5.2 \times 10^{21} / (6.02 \times 10^{23})\\ \phantom{n(\text{C}_3\text{H}_7\text{OH})} = 8.6 \times 10^{-3} \; \text{mol}

where N_A = 6.02 \times 10^{23}\; \text{mol}^{-1} the Avogadro's constant that relates the number of particles to their number, in the unit moles \text{mol}.

The molar mass of propanol- mass per mole propanol- can be directly deduced from its molecular formula with reference to a modern periodic table.

M(\text{C}_3\text{H}_7\text{OH}) = \underbrace{3 \times 12.01}_{\text{carbon}} + \underbrace{8 \times 1.008}_{\text{hydrogen}} + \underbrace{1\times 16.00}_{\text{oxygen}} = 60.09 \; \text{g} \cdot \text{mol}^{-1}

8.6 \times 10^{-3} \; \text{mol} of propanol molecules would thus have a mass of 8.6 \times 10^{-3} \; \text{mol} \times 60.09 \; \text{g} \cdot \text{mol}^{-1} = 0.52 \; \text{g}

5 0
3 years ago
What is the mass of 5.119 102 molecules of copper sulfate<br> (CuSO4)?
Amiraneli [1.4K]

Answer:

Mass = 135.66 ×10⁻²¹ g

Explanation:

Given data:

Number of molecules of CuSO₄= 5.119×10²

Mass of CuSO₄= ?

Solution:

The given problem will solve by using Avogadro number.

1 mole contain 6.022×10²³ molecules

5.119×10² molecules ×1 mol / 6.022×10²³ molecules

0.85×10⁻²¹ mol

Mass in grams:

Mass = number of moles × molar mass

Mass = 0.85×10⁻²¹ mol × 159.6 g/mol

Mass = 135.66 ×10⁻²¹ g

7 0
2 years ago
The atomic nucleus contains two subatomic particles, the proton and the neutron. Atoms of different elements have different numb
Nostrana [21]

Answer:

The correct option is;

A) 1 to 1.

Explanation:

A stab;e nuclei requires the presence of a neutron to accommodate the the protons repulsion forces within the nucleus. An increase in the number of protons should be accompanied by an even more instantaneous increase in the number of neutrons to balance the forces in the nucleus. If there is an excess of neutrons or a deficit in protons a state of unbalance exists in the nucleus, which results to nuclear instability.

Therefore, the ratio of neutrons to protons is an appropriate way in foretelling nuclear stability and a stable nuclei is known to have a proton to neutron ratio of 1:1 and the number of protons and neutrons in the stable nuclei are usually even numbers.

4 0
2 years ago
Which element, represented by X, reacts with oxygen to produce the compound X2O?
natali 33 [55]

Answer:

lithium

Explanation:

this is because lithium has a valency of 1 and oxygen has a valency of 2 thereby exchanging valency to create Li²0

7 0
3 years ago
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