Lab Flow Pre-Lab Quizzes (start-3)

When inputting a formula into Excel or other spreadsheet software, what components are required for the formula to function properly?

-Closing parentheses for any opening parentheses -An equal sign at the beginning of the formula

All lab participants must remain prepared to use safety equipment in case of emergency. Identify the components of effective preparation.

-Knowing what safety equipment is available -Understanding where the safety equipment is located -Being familiar with how safety equipment is used

When using a properly stabilized balance, how should you ensure that you get the most accurate mass reading possible?

-Measure the mass of the sample at room temperature -Close the side shields on the balance during reading

While setting up a beaker to boil a solution on a hot plate, you notice that the stirring is erratic and unstable. What should you do to stabilize the stirring solution?

-Move the beaker to the center of the hot plate -Turn down the stirring speed.

What visible signs indicate a precipitation reaction when two solutions are mixed?

-Solid settling out in the test tube -A hazy or cloudy appearance

Changing gloves often will minimize the spread of chemicals. To properly remove gloves, first, .........................., and then, .........................., then insert, ........................ between the interior edge of the second glove and the skin, and remove the second glove.

-grasp the exterior of one glove with a gloved hand -peel off the first glove -a bare finger

What to remove from body when working in a lab? What to tie back or secure?

-long necklaces, long earrings, loose bracelets -long hair, flow sleeves

What should you do every time before you leave the lab?

1) Remove your labcoat, if you are wearing one. 2) Remove your gloves 3) Wash your hands

Identify which balance was used to make each mass reading for 4.0000 g

A balance with ±0.0001 g tolerance

Suppose you mix NaCl and AgNO3 solutions according to the given equation NaCl(aq)+AgNO3(aq)⟶AgCl(s)+NaNO3(aq) What evidence of a reaction do you expect to see?

A precipitate should form

The majority of silver salts are not soluble in water. ............, is one common exception.

AgNO3

What is the best safety approach when working with unknown chemical substances?

Assume that the substance is hazardous. Always wear appropriate PPE and take steps to prevent contact

Where to dispose of each type of waste? Broken Flask Unused Solid Reagent Syringe Tips Titrant solution

Box lined with puncture resistant bag Solid waste container Sharps container Nalgene bottle with cap

Which compounds could be represented by the empirical formula CH2?

C8H16 C2H4 C3H6 MULTIPLES OF IT

Which chemical waste situation should always be supervised or performed by an instructor?

Cleaning up a broken mercury thermometer

How do you determine the last digit in any measured number?

Estimate one digit past the smallest precisely known digit or marking

Predict the products of hydrochloric acid (HCl) reacting with zinc metal.

H2 & ZnCl2

Which procedure cannot be performed on a hot plate, requiring a Bunsen burner instead?

Heating a crucible to remove water from a hydrate

Where should glassware be stored after it is cleaned?

In a drying oven, or designated locations such as drawers or buret racks

King Henry Doesn't Usually Drink Chocolate Milk

Kilo, Hecto, Deka, Unit, Deci, Centi, Milli

Identify the precautions to take with exits in the lab.

Locate the exits prior to the start of lab. Do not block a door with an EXIT sign

To identify a combustion reaction.........

O2 needs to be a reactant on the left side of the reaction arrow.

⟶

Substances on the reactants side are converted to the substances on the products side

Under what conditions should a student inform the instructor of a lab injury?

The instructor must be informed of all laboratory injuries.

+

There are two separate substances on either the products side or the reactants side.

What is the main precaution to take if a Gas Cylinder sign is present in the lab?

Visually check that the gas cylinder is restrained but keep a safe distance from it.

When should remove your goggles?

When everyone in the room is done handling any chemicals or glassware

double replacement reaction

a chemical reaction between two compounds where the positive ion of one compound is exchanged with the positive ion of another compound

combustion reaction

a chemical reaction that occurs when a substance reacts with oxygen, releasing energy in the form of heat and light 2C2H2(g)+5O2(g)⟶4CO2(g)+2H2O(l)

decomposition reaction

a reaction in which a single compound breaks down to form two or more simpler substances

what is used to pour an approximate volume of liquid into a buret?

beaker

Suppose you mix two solutions in a test tube and the test tube becomes hot. This is a sign of a ............ because ............

chemical reaction chemical changes can release heat.

Identify the common indicators that a chemical reaction has occurred.

color change, bubbles, precipitate formed, change in temp.

When cleaning a buret, begin by coating the inside with ............ Empty most of it out, then drain the rest by.................. Rinse with .................., then hang upside-down on a buret rack.

detergent solution opening the stopcock deionized water

what is used to Contain a stirred reaction mixture?

erlenmeyer flask

what to use in a... clothing fire small bench top fire large fire on floor

fire blanket overturned beaker fire exinguisher

If you drop or break glassware in lab, first ....... . Then, ........................ Finally, place all that material into ..............

get thick gloves or dustpan carefully collect all the broken glassware. the broken glass container.

what is used to measure the volume of a liquid?

graduated cylinder

In the presence of mineral oil, the ............... will dissolve in the oil and the .......... will remain in the aqueous layer.

halogen salt

Δ→

heat is applied

Density

mass/volume

ruler sig figs

one digit past decimal point

graduated cylinder sig figs

one digit past decimal point (40.5)

Single Replacement

one element replaces another element in a compound

When using the Tare function on a balance, start by....................... . Then, ...................... to cancel out that mass. Finally, .................... and record the mass of your sample.

placing the glassware on the balance press the Tare/Zero button add your sample to the glassware

multiplying and dividing sig figs

round to least number of sig figs

adding and subtracting sig figs

round to the least number of decimal places

Which of the following forms precipitates with most halogens?

silver nitrate

Move to the safety shower if you spill hazardous chemicals on your .................. Stand under the shower and ........... the lever. Remove clothing and continue flushing the area for .............

skin or clothing pull 15 minutes

If the unknown halide is a ............... reducing agent than chlorine, the halide will be oxidized to .................. which would change the color of the ............... layer.

stronger its elemental form mineral oil

to isolate a single variable when rearranging equations, move all other variables to ............... of the equation by using .............. on them and remembering to perform that operation ......................... Make sure the rearrangement has the target variable .................................

the other side the opposite function on both sides of the equation in the numerator, not the denominator.

(l)

the substance is liquid

combination reaction

two or more substances react to form one product

In a precipitation reaction, what symbol identifies the precipitate product?

(s)

What purposes can funnels serve in the lab?

-Assistance for pouring liquids into burets -Support for filter paper during a gravity filtration -Help for transferring solid chemicals from weigh boats

What parts are present in every chemical equation?

-At least one product -At least one reactant -arrow

What are the best practices while sharing a lab balance with other students?

-Brush off any chemical dust around the balance after each use -Alert your TA or instructor about any issues with the balance