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kondaur [170]
3 years ago
15

Scientists are studying fertilizers to help grass grow in southern California. Fertilizer is any substance that can be added to

soil to help plants grow in it. In other words, fertilizer makes soil more fertile. The scientists set up different plots of land that all use the same type of soil and grass seed, but they use different types of fertilizer in each plot. Scientists then measure the grass growth in the different soils over time.
How should scientists set up the control group in this experiment?

A - a plot with grass seed but no fertilizer in the soil
B - a plot with grass seed and many types of fertilizer in the soil
C - a plot without any grass seed or any fertilizer in the soil
D - a plot without any grass seed but with fertilizer in the soil
Chemistry
2 answers:
blsea [12.9K]3 years ago
7 0
A) plot with grads seed / no fertiliser in the soil
Andrej [43]3 years ago
6 0

Answer:

The answer should be A

Explanation:

A control is basically something to compare the experiment to. In other words, to see how the object does on its own versus how it would do with added substances

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A 2.00-mol sample of hydrogen gas is heated at constant pressure from 294 K to 414 K. (a) Calculate the energy transferred to th
Furkat [3]

Answer:

a) The energy transferred is 6.91 kJ

b) The internal energy is 4.90 kJ

c) The work done on the gas is - 2.01 kJ

Explanation:

Step 1: Data given

Number of moles of hydrogen gas = 2.00 moles

Pressure = constant

Temperature is heated from 294 K to 414 K

Molar heat capacity of hydrogen gas = 28.8 J/mol*K

Step 2: Calculate the energy transferred to the gas by heat.

Q = n* Cp * ΔT

⇒with Q =the energy transferred

⇒with n = the number of moles = 2.00 moles

⇒with Cp = the Molar heat capacity of hydrogen gas = 28.8 J/mol*K

⇒ with ΔT = Temperature 2 - Temperature 1 = 414 - 294 = 120K

Q = 2.00 * 28.8 * 120

Q = 6912 J = 6.91 kJ

Step 3: Calculate the increase in its internal energy.

ΔEint = n*Cv*ΔT

⇒with ΔEint = the increase in its internal energy.

⇒with n = the number of moles = 2.00 moles

⇒with Cv = The constant volume = 20.4 J/mol*K

⇒with  ΔT = Temperature 2 - Temperature 1 = 414 - 294 = 120K

ΔEint = 2.00 * 20.4 * 120

ΔEint =4896 J = 4.90 kJ

Step 4: Calculate the work done on the gas.

Work done on the gas = -Q + ΔEint

W = -6.91 kJ + 4.90 kJ

W = -2.01 kJ

6 0
3 years ago
Desclony When Fe(NO3)2 dissolves in water, what particles are present in the solution?​
Hitman42 [59]

Answer:

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3 0
3 years ago
What is the general trend for electron affinity values going across a period? The
k0ka [10]

Answer: The values become more negative

Explanation: I just took the quiz and got it correct :)

5 0
3 years ago
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Which statement best describes the pH of pure water?
Ray Of Light [21]

The pH of pure water is neutral because the concentration of hydronium ions equals that of hydroxide ions.

Answer: Option A

<u>Explanation:</u>

Water is one of the most important constituents of living being. It is said that there is no life without water. So that water need to neutral in nature to save life. Pure water is composed of hydronium H^{+} and hydroxide \left(O H^{-}\right) ions. It is known that hydronium ions are acidic in nature with concentration of 1 \times 10^{-7} \mathrm{M} / \mathrm{L}.

Similarly, the hydroxide ions which are basic in nature will be in same concentration as that of hydronium ions. So, as the concentration of basic and acidic elements are equal with the same strength of pH, the combination of these ions lead to formation of pure water with the pH being neutral.

7 0
3 years ago
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A ball has a mass of 140 g. What is the force needed to accelerate the ball at 25 m/s2? (Formula: F=ma) 3.5 N 115 N 165 N 4.5
Ksju [112]
<h3>Answer:</h3>

3.5 Newton

<h3>Explanation:</h3>

We are given;

Mass of the ball = 140 g

Acceleration = 25 m/s²

Required to find the force;

  • According to Newton's second law of motion, the resultant force on a body in motion and the rate of change in linear momentum are directly proportional.
  • That is; F \alpha \frac{Mv-Mu}{t}
  • Thus; F = ma , where F is the resultant force, m is the mass and a is the acceleration.

To get the force we substitute the value of m and a in the formula;

Therefore;

F = 0.14 kg × 25 m/s²

  = 3.5 N

Hence, the force needed to accelerate the ball is 3.5 N

3 0
3 years ago
Read 2 more answers
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