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vladimir1956 [14]
3 years ago
14

MULTIPLE CHOICE QUESTION

Chemistry
1 answer:
zubka84 [21]3 years ago
4 0

Answer:

This question will be answered based on general understanding of how a controlled experiment should be:

The answer is: We must make sure we are testing/changing only one variable, and controling others

Explanation:

A controlled experiment is an experiment in which the independent variable is changed for a particular group called the EXPERIMENTAL group and unchanged for another group called the CONTROL group.

In a controlled experiment, only one variable should be tested while the others should be kept constant in order to have an effective result or outcome. This is the case in this question, the type of music or soil should be unchanged for each plant because the experimenter must make sure that he/she is testing/changing only one variable, and controling others.

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Why do scientists look for patterns in the world?
PSYCHO15rus [73]

Answer:

B. Patterns can help explain observations.

Explanation:

Hope this helps

6 0
3 years ago
True or False: If you have 2 moles of water and 2 moles of carbon, you have the same number of molecules.
nikklg [1K]
True.
moles x avagadro number = molecules
8 0
3 years ago
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Elements that have atoms with stable valence electron configurations in the ground state are found in
dsp73

Answer:

Group 18, also known as the Noble Gasses

Explanation:

Atoms strive for full stability by gaining or losing electrons to get 8 valence electrons in their valence shell, but Group 18 already has 8 electrons in their valence shell, and are therefore already stable in their ground state.

5 0
3 years ago
A 10 mm Brinell hardness indenter is used for some hardness testing measurements of a steel alloy. a) Compute the HB of this mat
Lady_Fox [76]

Explanation:

(a)  The given data is as follows.  

         Load applied (P) = 1000 kg

         Indentation produced (d) = 2.50 mm

         BHI diameter (D) = 10 mm

Expression for Brinell Hardness is as follows.

                HB = \frac{2P}{\pi D [D - \sqrt{(D^{2} - d^{2})}]}    

Now, putting the given values into the above formula as follows.

                HB = \frac{2P}{\pi D [D - \sqrt{(D^{2} - d^{2})}]}                            = \frac{2 \times 1000 kg}{3.14 \times 10 mm [D - \sqrt{((10 mm)^{2} - (2.50)^{2})}]}  

                       = \frac{2000}{9.98}                          

                       = 200

Therefore, the Brinell HArdness is 200.

(b)     The given data is as follows.

               Brinell Hardness = 300

                Load (P) = 500 kg

               BHI diameter (D) = 10 mm

             Indentation produced (d) = ?

                      d = \sqrt{(D^{2} - [D - \frac{2P}{HB} \pi D]^{2})}

                         = \sqrt{(10 mm)^{2} - [10 mm - \frac{2 \times 500 kg}{300 \times 3.14 \times 10 mm}]^{2}}

                          = 4.46 mm

Hence, the diameter of an indentation to yield a hardness of 300 HB when a 500-kg load is used is 4.46 mm.

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How many elements in this compound: HClO<br> 1<br> 2<br> 3<br> 4
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There are three elements hydrogen, chlorine, and oxygen
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