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vfiekz [6]
3 years ago
11

Calculate the mass of a sample of lead (cPb = 0.16 J/g℃) when it loses 200 J cooling from 75.0℃ to 42.0℃.

Chemistry
1 answer:
egoroff_w [7]3 years ago
7 0
Looses 299 please collins 75.0
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Scientific method quick check
soldi70 [24.7K]

Answer:

Quick you said:

-Purpose/Question

Ask a question.

-Research

Conduct background research. Write down your sources so you can cite your references. In the modern era, a lot of your research may be conducted online. Scroll to the bottom of articles to check the references. Even if you can't access the full text of a published article, you can usually view the abstract to see the summary of other experiments. Interview experts on a topic. The more you know about a subject, the easier it will be to conduct your investigation.

-Hypothesis

Propose a hypothesis. This is a sort of educated guess about what you expect. It is a statement used to predict the outcome of an experiment. Usually, a hypothesis is written in terms of cause and effect. Alternatively, it may describe the relationship between two phenomena. One type of hypothesis is the null hypothesis or the no-difference hypothesis. This is an easy type of hypothesis to test because it assumes changing a variable will have no effect on the outcome. In reality, you probably expect a change but rejecting a hypothesis may be more useful than accepting one.

-Experiment

Design and perform an experiment to test your hypothesis. An experiment has an independent and dependent variable. You change or control the independent variable and record the effect it has on the dependent variable. It's important to change only one variable for an experiment rather than try to combine the effects of variables in an experiment. For example, if you want to test the effects of light intensity and fertilizer concentration on the growth rate of a plant, you're really looking at two separate experiments.

-Data/Analysis

Record observations and analyze the meaning of the data. Often, you'll prepare a table or graph of the data. Don't throw out data points you think are bad or that don't support your predictions. Some of the most incredible discoveries in science were made because the data looked wrong! Once you have the data, you may need to perform a mathematical analysis to support or refute your hypothesis.

-Conclusion

Conclude whether to accept or reject your hypothesis. There is no right or wrong outcome to an experiment, so either result is fine. Accepting a hypothesis does not necessarily mean it's correct! Sometimes repeating an experiment may give a different result. In other cases, a hypothesis may predict an outcome, yet you might draw an incorrect conclusion. Communicate your results. The results may be compiled into a lab report or formally submitted as a paper. Whether you accept or reject the hypothesis, you likely learned something about the subject and may wish to revise the original hypothesis or form a new one for a future experiment.

7 0
3 years ago
Lactic acid results from which of the following?
vazorg [7]

Explanation:

Lactic acid is formed during the breakdown of glucose. This is sometimes called "blood sugar."

7 0
3 years ago
Read 2 more answers
A buffer solution contains 0.479 M NaHCO3 and 0.342 M Na2CO3. Determine the pH change when 0.091 mol HNO3 is added to 1.00 L of
pshichka [43]

Answer:

ΔpH = 0.20

Explanation:

The buffer of HCO₃⁻ + CO₃²⁻ has a pka of 10.2

HCO₃⁻ ⇄ H⁺ + CO₃²⁻

There are 0.479moles of NaHCO₃ and 0.342moles of Na₂CO₃.

Using Henderson-Hasselbalch formula:

pH = pka + log [Base] / [Acid]

pH = 10.2 + log 0.342mol / 0.479mol

<em>pH = 10.05</em>

NaOH reacts with HCO₃⁻ producing CO₃²⁻, thus:

NaOH + HCO₃⁻ → CO₃²⁻ + H₂O + Na⁺

0.091 moles of NaOH produce the same moles of CO₃²⁻ and consume HCO₃⁻. Moles of these species are:

CO₃²⁻: 0.342mol + 0.091mol: 0.433mol

HCO₃⁻: 0.479mol - 0.091 mol: 0.388mol

Using Henderson-Hasselbalch formula:

pH = pka + log [Base] / [Acid]

pH = 10.2 + log 0.433mol / 0.388mol

pH = 10.25

That means change of pH, ΔpH is:

ΔpH = 10.25 - 10.05 = <em>0.20</em>

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I hope it helps!

3 0
3 years ago
What is what is the balanced formula equation for Solutions of lead nitrate and lithium chloride
Burka [1]
Can i get a list of possible answers plz?
3 0
4 years ago
All organic compound soluble in WATEe and conduct electrically ​
Delvig [45]

No

Explanation:

Not all organic substances are soluble in water and will not conduct electricity. Only polar organic compounds are soluble in water and will conduct electricity.

  • The general rule of solubility is that like dissolves likes.
  • Polar compounds will only dissolve other polar compounds too. Water is a polar solvent.
  • Non-polar compounds will only dissolve in non-polar compounds too.
  • Since water is a polar organic compound, only polar organic compounds will dissolve in it.
  • Not all organic compounds are polar.
  • When a compound dissolves in water, it produces ions that makes it able to conduct electricity.
  • Fats and oil are insoluble in water

learn more:

Inorganic compounds brainly.com/question/5047702

#learnwithBrainly

4 0
3 years ago
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