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Oduvanchick [21]
3 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]3 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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Which is an example of making a quantitative observation?
Elanso [62]

Answer:

A) measuring mass of metal used in a reaction

Explanation:

Quantitive observations is data involving statistics and numerical values.

4 0
3 years ago
Which of the following sign does not indicate that a chemical change has happened .
Sever21 [200]

Answer:

A.)

Explanation:

A change in state may seem like a chemical reaction, but it is actually a physical change. "A change in state" is basically saying that the appearance of whatever the item is, is taking a change physically. Whether this item was going through some examples of a physical change, which would be:

<em>melting (solid to liquid), evaporation (liquid to gas), condensation (gas to liquid), freezing (liquid to solid), deposition (gas to solid), and sublimation (solid to gas).</em>

A change in color, odor, taste, chemical compound, and temperature all represent a chemical reaction, because these are all things that are happening within the the item that is being given the product of a chemical change.

Think of it this way: <em>internal changes within the product: chemical. External changes within the product: physical.</em>

I hope this helps.

4 0
2 years ago
What type of subatomic particles are found in the cloud?
Novay_Z [31]

Answer:

Electrons are particles that surround the nucleus of an atom like a cloud. As with protons and neutrons, electrons are essential to an atom's structure.

8 0
3 years ago
What is the overall process of balancing an equation?
monitta

Answer:

You need to make sure the number of atoms of each element on the reactant side is equal to the number of atoms of each element on the product side. In order make both sides equal, you will need to multiply the number of atoms in each element until both sides are equal. :)

3 0
3 years ago
what is the molarity of a solution made by dissolving 18.5 grams of NaCL into enough water to reach 450.0ML​
ValentinkaMS [17]

Answer:

0.702M

Explanation:

Molarity of a solution, which refers to the molar concentration of that solution can be calculated thus;

Molarity = number of moles (n) ÷ volume (V)

Firstly, we convert 18.5 grams of NaCl to moles using the formula; mole = mass/molar mass

molar mass of NaCl = 23 + 35.5 = 58.5g/mol

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Molarity = n/V

Molarity = 0.32/0.450

Molarity = 0.702M

4 0
3 years ago
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