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3 years ago

A scientist grew bacteria on gel in her lab.

Chemistry

1 answer:

Neporo4naja [7]3 years ago

7 0

Answer:

The independent variable is type of gel and the dependent variable is the number of bacteria.

Explanation:

An experiment generally tests how one variable is affected by another. The affected variable is called the dependent variable. In the plant experiment shown above, the dependent variable is plant growth. The variable that affects the dependent variable is called the independent variable. In the plant experiment, the independent variable could be fertilizer—some plants will get fertilizer, others will not. The scientists change the amount of the independent variable (the fertilizer) to observe the effects on the dependent variable (plant growth). An experiment needs to be run simultaneously in which no fertilizer is given to the plant. This would be known as a control experiment. In any experiment, other factors that might affect the dependent variable must be controlled. In the plant experiment, what factors do you think should be controlled? (Hint: What other factors might affect plant growth?)

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If an electron gains energy what may happen to it

Illusion [34]

It could get bigger or it could have something a lot different to it than anything else

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3 years ago

An ecologist counts 75 cardinals in an area measuring 15 square kilometers. What is the population density of the cardinals?

Rom4ik [11]

Answer:

Explanation:

We know that,

number of count of cardinals = 75; and

measured area = 15 square kilometers.

To find the population density of the cardinals in an area of 15 square kilometers, we need to divide the number of cardinals by the given unit area:

Population density of cardinals = 75 / 15 = 5

Therefore, the population density of cardinals in an area measuring 15 square kilometers is 5.

8 0

3 years ago

Read 2 more answers

Classify each orbital diagram for ground-state electron configurations by the rule or principle it violates.

nignag [31]

Thank you for posting your question here at brainly. I hope the answer will help. Please see below:

Aufbau violation:
4s ↑↓ 3d ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ 5s ↑
3s ↑ 3p ↑ ↑ ↑ 
Hund violation: 
4s ↑↓ 3d ↑↓ ↑ ↓ ↑ ↑ 
3s ↑↓ 3p ↑↓ ↑↓
Pauli violation
2s ↑↑ 2p ↑ ↑ ↑

6 0

4 years ago

How many moles of NaF are produced in the resction between sodium bromide and calcium fluoride when 550 grams of sodium bromide

bija089 [108]

Answer: 5 moles of NaF would be produced when 550 grams of Sodium bromide are used.

Explanation:

From the question, the balanced chemical formula is illustrated below:

2NaBr + CaF2 → 2NaF + CaBr2

From the equation above;

Molecular mass of NaBr = 23 + 80 = 103g/ mol

Molecular mass of CaF2= 40+ (19×2)= 78g/ mol

Molecular mass of NaF = 23+19 = 42g/ mol

From the balanced chemical equation;

2 moles of NaBr reacted with 1mole of CaF to give 2 moles of NaF.

That is, 2 moles of NaBr= 2× 103 = 206g

2moles of NaF = 2×42= 84g

If 206g of NaBr yielded 84g of NaF

Therefore 550g of NaBr will yield Xg of NaF

X= 550×84/206

X= 224.27g of NaF

But 42g = 1 mole of NaF

Therefore 224.27g = X mole of NaF

X= 224.27 ×1/42

X is approximately 5moles.

6 0

3 years ago

Paradichlorobenzene, a common ingredient in solid air fresheners, contains only C, H, and Cl and has a molar mass of about 147 g

kakasveta [241]

Answer:

Empirical formula

C3H2Cl

Molecular formula

C6H4Cl2

Explanation:

Firstly, we can get the mass of carbon and hydrogen produced by calculating their number of moles from that of carbon iv oxide and water respectively.

To get the number of moles of carbon iv oxide, we simply make a division. The number of moles is the mass of carbon iv oxide divided by the molar mass of carbon iv oxide. The molar mass of carbon iv oxide is 44g/mol. The number of moles is thus 3.02/44 = 0.069

One atom of carbon is present in Carbon iv oxide. This means 0.069 moles of carbon is present. The mass of carbon present equals the atomic mass of carbon multiplied by the number of moles = 0.069 * 12 = 0.83g

The mass of water is 0.412g, the number of moles is 0.412/18 = 0.023

In water, there are two atoms of hydrogen. Hence the number of moles of hydrogen is 2 * 0.023 = 0.046

The mass of hydrogen is the number of moles of hydrogen multiplied by the atomic mass unit of hydrogen = 0.046 * 1 = 0.046g

Now we need to know the mass of chlorine. We simply subtract the masses of hydrogen and carbon.

1.68-0.046-0.83 = 0.804

Now we proceed to calculate the empirical formula. We simply divide the mass of each by their atomic masses and then proceed from there.

H = 0.046/1 = 0.046

C = 0.83/12 = 0.069

Cl = 0.804/35.5 = 0.023

We divide by the smallest number which is that of that of carbon

H = 0.046/0.023= 2

C = 0.069/0.023= 3

Cl = 0.023/0.023 = 1

The empirical formula would thus be C3H2Cl

The molecular formula can be calculated using the molar mass;

(C3H2Cl)n = 147

(36+ 2 + 35.5 ) = 147

73.5n = 147

n = 147/73.5 = 2

The molecular formula is thus C6H4Cl2

6 0

3 years ago