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PIT_PIT [208]
3 years ago
12

Ill give u brainliest pls help i only have until 1:00!

Chemistry
2 answers:
garik1379 [7]3 years ago
8 0

Astronomers would use astronomical units when measuring objects in a solar system. Lightyears would be used when measuring objects outside of our solar system.

Answer: When measuring in a solar system

gain integrity

OLEGan [10]3 years ago
7 0

Perhaps when they are trying to find the distance of an asteroid to the Earth to find out whether or not it is a hazard to Earth.

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Please help! its due at the end of class.
Vera_Pavlovna [14]

Answer:

2.down is hypotheses and 23.across is experiment

Explanation:

akechis pancakes

5 0
3 years ago
Describe at least two experiments, including the observed results, that caused the scientific community to accept changes to Dal
WINSTONCH [101]
The model after John Dalton's was J.J Thompson's plum podding model in 1897, which described electrons as dots or raisins(if you will) in a circle shaped pudding that was entirely positive using a Cathode Ray Tube(shot cathode rays between magnets). The model after that is the Niels Bohr model in 1913, which depicts atoms like positively charged center called the nucleus with negatively charged particles called electrons in a shell or cloud.
5 0
4 years ago
Which would be the best to neutralize a large acid spill in your school lab: sodium hydroxide or baking soda? Explain.
nadya68 [22]

Consider the acid spill. It is already starting to do nasty things to, say, the floor or counter. So you grab the bottle of 10% NaOH and pour some on the spill. All of a sudden, you get a great deal of heat, and you don't have any visual evidence whether your put on too little or too much. But you have added more liquid to the spill, generated more heat, and will get more damage. You have made a bigger mess, and if you added too much, you then have a neutralization problem to deal with.  

And if it is something like a strong sulfuric acid solution, adding sodium hydroxide solution will be extremely exothermic, and you could get some really nasty results.  

So now approach the spill with a handful of baking soda. You sprinkle it on the spill. It fizzes, and carbon dioxide is given off. That actually, in a very tiny way, moderates the temperature of the neutralization. And you can keep adding baking soda until the fizzing stops, and then perhaps some water to mix everything well. But what you have done is kept the volume to a minimum, added a neutralization agent that has a visible endpoint (no more gas being given off), and you don't suddenly have a huge amount of highly basic solution because you added too much.  

And what is also nice about baking soda is that you can toss some with your hand or even with a spoon, and get some distance from the spill. With a liquid, you have to get much closer

i hope this helped..

5 0
3 years ago
Calculate the change in pH when 71.0 mL of a 0.760 M solution of NaOH is added to 1.00 L of a solution that is 1.0O M in sodium
Eddi Din [679]

Explanation:

It is known that pK_{a} value of acetic acid is 4.74. And, relation between pH and pK_{a} is as follows.

                    pH = pK_{a} + log \frac{[CH_{3}COOH]}{[CH_{3}COONa]}

                          = 4.74 + log \frac{1.00}{1.00}

So, number of moles of NaOH = Volume × Molarity

                                                   = 71.0 ml × 0.760 M

                                                    = 0.05396 mol

Also, moles of  CH_{3}COOH = moles of CH_{3}COONa

                                          = Molarity × Volume

                                          = 1.00 M × 1.00 L

                                          = 1.00 mol

Hence, addition of sodium acetate in NaOH will lead to the formation of acetic acid as follows.

            CH_{3}COONa + NaOH \rightarrow CH_{3}COOH

Initial :    1.00 mol                                  1.00 mol

NaoH addition:               0.05396 mol

Equilibrium : (1 - 0.05396 mol)    0           (1.00 + 0.05396 mol)

                    = 0.94604 mol                       = 1.05396 mol

As, pH = pK_{a} + log \frac{[CH_{3}COONa]}{[CH_{3}COOH]}

               = 4.74 +  log \frac{0.94604}{1.05396}

               = 4.69

Therefore, change in pH will be calculated as follows.

                         pH = 4.74 - 4.69

                               = 0.05

Thus, we can conclude that change in pH of the given solution is 0.05.

8 0
3 years ago
I made a cup of coffee on the stove and when I went to check on it four hours later, there was no more water in the kettle.
11Alexandr11 [23.1K]
No the water evaporated 
i think :) :) 

3 0
3 years ago
Read 2 more answers
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