Base your answers to questions 76 through 79 on the information below and on your knowledge of chemistry.During a laboratory activity, a student places 25.0 mL of HCl(aq) of unknown concentration into a flask. The student adds four drops of phenolphthalein to the solution in the flask. The solution is titrated with 0.150 M KOH(aq) until the solution appears faint pink. The volume of KOH (aq) added is 18.5 mL.

76 What number of significant figures is used to express the concentration of the KOH (aq)?

77 Complete the equation in your answer booklet for the neutralization reaction that occurs during the titration.

HCl + KOH--> ________________

78 Determine the concentration of the HCl(aq) solution, using the titration data.

79 Describe one laboratory safety procedure that should be used if a drop of the KOH(aq) is spilled on the arm of the student.

Answers

Answer 1
Answer:

The precaution taken when KOH is dropped on the arm of a student is to apply plenty water over the affected area.

What is titration?

The term titration has to do with a reaction between an acid and a base to form salt and water only.

In this reaction, we have; KOH + HCl -----> KCl + H2O. The concentration of KOH was expressed to two significant figures.

The concentration of HCl is obtained from;

0.150 M * 18.5 mL * 1/25.0 mL * 1 = 0.11 M

The precaution taken when KOH is dropped on the arm of a student is to apply plenty water over the affected area.

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Answer 2
Answer: 76. 3 significant figures
77. KCl +H(little)2O
78. 0.1M
79. rinse it off with water or tell the teacher
Hope this helps :)

Related Questions

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Protons inside the nucleus of an atom are held together though they have the same charge because?
Which of the following elements has the strongest attraction for electrons? a. oxygen b. sulfur c. aluminum d. boron
What is the volume of an object whose dimensions are 5.54 cm, 10.6 cm, and 199 cm?
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an organic compound on analysis yielded 2.04g carbon, 0.34g hydrogen, 2.73g oxygen. calculate the empirical formula​

Answers

Answer:

CH2O

Explanation:

According to this question:

C = 2.04g

H = 0.34g

O = 2.73g

First, we divide the mass value of each element by its atomic mass to convert to moles.

C = 2.04g ÷ 12 = 0.17mol

H = 0.34g ÷ 1 = 0.34mol

O = 2.73g ÷ 16 = 0.17mol

Next, we divide by the smallest mole value (0.17):

C = 0.17mol = 0.17 = 1

H = 0.34mol ÷ 0.17 = 2

O = 0.17mol ÷ 0.17 = 1

The whole number ratio of C,H,O is 1:2:1, hence, the empirical formula is CH2O.

Solutions of mercury (I) nitrate and potassium bromide are mixed

Answers

With that informatio you can:

1) Write the chemical equation
2) Balance the chemical equation
3) State the molar ratios
4) Predict if precipitation occurs.

I will do all four, for you:

1) Chemical equation:

mercury(I) nitrate  potassium bromide    mercury(I) bromide  potassium nitrate
Hg2(NO3)2             +        KBr                   → Hg2Br2          +      KNO3

2) Balanced chemical equation

Hg2(NO3)2 + 2KBr → Hg2Br2 + 2KNO3

3) Molar ratios or proportions:

1 mol
Hg2(NO3)2 : 2 mol KBr : 1 mol Hg2Br2 : 2 mol KNO3

4) Prediction of precipitation.

You can use the solubility rules or a table of solubilities. I found in a table of solutiblities that mercury(I) bromide is insoluble and potassium bromide is soluble, Then you can predict that the precipitation of mercury(I) bromide will occur.


Can someone please take a look at this lab.? And show answers with work? Thanks! I tried it but I'm pretty sure I did it all wrong.

Answers

Answer: B

Explanation:

All of your answers look wrong

State, in terms of the arrangement of atoms, the difference in hardness between diamond and graphite.

Answers

The difference in hardness between diamond and graphite is that diamond has an ordered arrangement of atoms within its structure that makes it harder and stronger than graphite. This is due to the high pressure and high temperature that it went.

Final answer:

Diamond is significantly harder than graphite due to its tightly packed arrangement of atoms, while graphite is soft and slippery because of its layered structure.

Explanation:

The difference in hardness between diamond and graphite can be explained by their arrangement of atoms. In diamond, each carbon atom is bonded to four neighboring carbon atoms in a tetrahedral arrangement, creating a rigid and tightly packed structure. This arrangement gives diamond its hardness. On the other hand, in graphite, each carbon atom is bonded to only three neighboring carbon atoms, forming layers that are held together by weak forces called van der Waals forces. These layers can slide past each other easily, making graphite soft and slippery.

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What is the balanced equation for methyl ethanoate using the condensed structural formulae

Answers

the answer is....CH3COOCH3

Which is an example of a highly unstable isotope that is often used in fission reactions? A. c-12
B. c-14
C. u-235
D. u-238

Answers

The right answer to this question is U-235. It is an isotope of Uranium and it is an unsteady heavy metal used in fission reactions because it can run long chains of reactions. I hope this helps.

Answer:

C. U-235

Explanation:

A fission reaction is one in which an unstable radioisotope breaks down into smaller nuclei when bombarded with energetic particles.

The highly unstable isotope that is often used in fission reactions is U-235. When bombarded with neutrons that atom breaks down to form krypton and barium along with the release of a large amount of energy. The reaction is given as:

₉₂U²³⁵ +  ₀n¹  →   ₃₆Kr⁸⁹  +  ₅₆Ba¹⁴⁴  + 3₀n¹ + 210 Mev energy