Chemistry, 14.10.2020 18:01, johnjohnthornhi17

Help me plz You are cleaning up a lab when you see a beaker of a clear substance that is unlabeled. Your teacher tells you that if you can figure out what is in the beaker she’ll give you some bonus points (WHOOHOO) so you get right to work and start by testing the pH. You first test, with pH paper ranging from 0-14 turns up a bright yellow color. You think you could get some more information so you decide to use the litmus paper that ranges from 4.5 - 7.5. When dipped into the sample, the paper turns up a very very dark purple - almost black. You’ve seen these results before - you know what’s in the mystery beaker! Now, you need to prove to your teacher that you figured it out!
write a claim evidence reasoning.

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answered: bartekzelazek5083

1 When you find an unlabeled bottle of chemical in the lab, you should:Smell it to see what it is

Ask your teacherWaft the chemicalPour it down the drain

2. If you break a beaker in the lab, the first thing you should do is:

Tell your teacherClean up the glassPut the broken glass in a separate container labeled broken glassCarefully use your hands to pick up the largest piece

3. When you complete your lab work, which of the following should you not do:

Clean & return materials to the lab cartTry your own experimentTurn in all lab work to your teacherReturn to your own seat

4. Which of the following procedures is not correct:

Add acid to waterPipette by mouthKeep flammables away from open flamesNever used chipped glass

5. What is the most important thing to do before starting a lab:

Put on gogglesPut on your lab apronPick up your materials from the lab cartRead the entire lab

6. When heating liquids in test tubes:

Always tightly cork the test tubehold the test tube pointing upwardHold test tubes at a slant pointed away from everyoneNone of the above

7. Which of the following is true about heating glass:

Only use glassware marked KimexOnly use glassware marked PyrexBoth A & B are correctAlways ask the teacher if the container can be heated

8. Which of the following is correct lab procedure:

Place heated glassware on countertops away from the edgeHold dissecting specimens tightly with your hand when cutting with a scalpelWear gloves when dissecting & dispensing irritating chemicalsPour excess chemical back into its original container

9. Which of the following statements is correct:

Never use cracked glasswareWash hands before & after dissectingTreat all chemicals as poisonousAll of the above

10. When inserting glass tubing into stoppers:

Use glycerin & a twisting motion

Hold the stopper tightly as you push the glass tubing into itInsert the tubing into the stopper under waterAlways ask your teacher to insert the glass tubing for you

answered: Guest

when 25.0 ml of 0.700 mol/l naoh was mixed in a calorimeter with 25.0 ml of 0.700 mol/l hcl, both initially at 20.0 °c, the temperature increased to 22.1 °c. the heat capacity of the calorimeter is 279 j/°c.

the equation for the reaction is:

naoh + hcl → nacl + h₂o

moles of hcl = 0.0250 l hcl ×

0.700

mol hcl

1 l hcl = 0.0175 mol hcl

volume of solution = (25.0 + 25.0) ml = 50.0 ml

mass of solution = 50.0 ml soln ×

1.00

ml soln

= 50.0 g soln

δt=t2-t1

= (22.1 – 20.0) °c = 2.1 °c

the heats involved are

heat from neutralization + heat to warm solution + heat to warm calorimeter = 0

q1+q2+q3=0

nδh+mcδt+cδt=0

0.0175 mol ×

δh

+ 50.0 g × 4.184 j·g⁻¹°c⁻¹ × 2.1 °c + 279 j°c⁻¹ × 2.1 °c = 0

0.0175 mol ×

δh

+ 439.32 j + 585.9 j = 0

0.0175 mol ×

δh

= -1025.22 j

δh=1025.22j0.0175 mol= -58 600 j/mol = -58.6 kj/mol

answered: Guest

can you list the answers so i can answer

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Help me plz You are cleaning up a lab when you see a beaker of a clear substance that is unlabeled....