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A conversation between two students in a chemistry class

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Listen to audio recording and answer the questions.

Listen to a conversation between two students in a chemistry class.

Marie: Huh! This isn't working.

Peter: What isn't?

M: This reaction. I'm supposed to get hydrogen gas, but I don't seem to be getting anything except air.

P: How are you supposed to tell?

M: Well, hydrogen gas should explode when I hold this burning splint up to the test tube- but... nothing happens, see?

P: Hmm. Very unimpressive. How do you do this experiment, again?

M: Well, I put some hydrochloric acid into this test tube here. And then I add a piece of zinc metal to it. A reaction takes place and hydrogen gas is produced- it says- which should come out of the glass tubing, over here, and go into this other test tube. But it doesn't.

P: Nothing happens?

M: Well, something happens. The zinc bubbles and bounces around- the acid does something to it. Some gas must be coming off, I guess, but it isn't flammable. It doesn't burn at all.

P: Is there any way else to identify hydrogen?

M: Not that I 've learned. It's completely colorless and tasteless, I know- it just burns very dramatically.

P: Huh. Well, I dunno. Shall we run through your experiment again together and see how it goes?

M: Sure, if you don't mind- that would be great! I'm sure I'm doing everything right, I've gone through it twice now, but I still get nothing, nada.

P: OK. Lessee.... We need what? Clean test tubes? Two of 'em? Here we are. And... a rubber stopper with ten centimeters or so of glass tubing through it... right...uh...here. That's it?

M: Yep. And a graduated cylinder and the Bunsen burner. And the zinc and the acid.

P: All right: let's do this first- let's take the zinc and the HCl from different sources- from, uh, those reagent bottles on that lab table over there. Maybe your bottles are contaminated or mislabeled or something.

M: Oh, good idea. Trust me to use the wrong reagents.

P: Just a sec.... here we are... OK, now you run the experiment like you think you should, and I'll watch what you do.

M: Well, first I clamp this test tube onto its stand...like this... and put in about five milliliters of the hydrochloric acid....

P: "About" five milliliters?! Isn't this a scientific laboratory?

M: All right, all right. Exactly five milliliters of HCl...like this....

P: OK. Mmm... and....

M: Then I take a little piece of zinc metal with these tweezers, like this, and-

P: Are they all the same size?

M: Yeah, they seem to be. It looks like they're pressed out of some kind of machine in standard bits.

P: And add "one"?

M: Yeah, one. Like this. And see?- it starts to bubble!

P: Sure does!

M: So I slap the stopper into the top of the test tube real quick, like- unh!- this....

P: Mmm....

M: And then, I hold the other test tube under the other end of the glass tubing, here...like this, and...uh, wait until I think I've collected enough hydrogen gas to ignite, I guess. Is the Bunsen burner going?

P: Yes, it's burning- and you also need a splint, right? Here's one. Hey! Just a minute- how in heck are you going to collect any gas like that?!

M: Like what?

P: Like that- holding the test tube under the mouth of the tubing

M: What? Am I spilling it or something?

P: No, no- you're losing it entirely! Hydrogen is lighter than air, Marie. It's floating UP.

M: Huh?

P: It's floating up. It's rising from the tube mouth. It's not falling into your container. Hold it above the tube!

M: Ack! How stupid! I am so stupid. I'm never gonna pass this course. OK, OK- now...light that for me, will you?

P: Right...here you go.

M: And.... POW! Wow, did you see that?

P: And we've got lift off! And you've got hydrogen. Congratulations.

M: Yeah. (sighs) Thanks, Peter. Now all I gotta do is write this experiment up.

P: No problem. So, what's your next experiment?

M: Uh, something about sodium and water.

P: Oh no!


How many chemicals are required for the girl's experiment?


Why does her experiment fail?

Listen again to part of the passage and answer the following question.


Why does the young man say this: "Isn't this a scientific laboratory?"


What is the goal of this conversation?


What will the young woman probably do next?


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