chem lab 116 (lab 1-3)

A block has a mass of 4.287 g and a volume of 126.9 cm3. Calculate the density in g/cm3.

0.034 g/cm^3 d=m/v

A 2.59 g piece of zinc (density = 7.14 g/mL) is added to a graduated cylinder that contains 12.13 mL H2OHX2O . What will be the final volume reading on the graduated cylinder, in mL?

12.50 mL V=2.59 g7.14 g/mLV=2.59 g7.14 g/mL The volume reading on the graduated cylinder is equal to the volume of zinc plus 12.13 mL.

Calculate the volume of a box, in cubic centimeters, which is 423 cm long, 12 cm wide, and 25 cm high. Report your answer with correct significant figures in cubic centimeters.

130000 cm^3 length x width x height

Calculate the volume of a box, in cubic centimeters, which is 423 cm long, 12 cm wide, and 25 cm high. Report your answer with correct significant figures in cubic centimeters.

130000 cm^3 volume of the box=length×width×height

A graduated cylinder contains 10.00 mL water. A 14.74 g piece of aluminum is added to the water, and the volume rises to 15.46 mL. What is the density of the aluminum in g/mL?

2.7 g/mL d=m/v

A 24.5 g sample of solution has a density of 0.768 g/mL. What is the sample volume (in mL)?

31.9 mL v=m/d

A series of measurements in the lab led to an experimental result of 32.9 mL, with a calculated standard deviation of 0.3 mL. What is the standard way to report this result?

32.9 ± 0.3 mL

Determine the number of significant figures in each measurement. Then, choose the representation of the number where x is in place of the estimated digit from the measurement. 14.8 m $10.25 0.05L 1.000 g/mL 6200 cm 403 kg

3;14.x 4;10.2x 1;0.0x 4;1.00x 2;6x00 3;40x

The density of water depends on its temperature 4.0000 g 6.539 g 5.43 g 0.90 g 1.230 g

A balance with ±0.0001 g tolerance A balance with ±0.001 g tolerance A balance with ±0.01 g tolerance A balance with ±0.01 g tolerance A balance with ±0.001 g tolerance

Identify techniques to be used for accurate solution preparation using a volumetric flask.

After the solvent is added, stopper and invert the flask to mix the solution. Read the liquid volume at eye level from the bottom of the meniscus

Why are physical properties such as color or particle size often inadequate for identification of chemical substances?

Color, particle size, or other physical properties of a substance may vary under certain conditions. Many different chemical substances may share the same physical appearance.

The equation to calculate density is _________, where D is the density, m is the ________, and V is the ______.

D=m/V mass volume

What is the goal of qualitative analysis?

Determining the composition of a substance

How do you determine the last digit in any measured number on a non-digital instrument?

Estimate one digit past the smallest precisely known digit or marking.

Which warning about iodine is accurate?

Iodine can stain the body and other surfaces.

Identify the observations that indicate an added substance is insoluble in water.

The combination of the substance and water appears cloudy after mixing and allowing to settle. The added solid settles to the bottom after mixing and allowing to settle A clear line appears between the added liquid and water after mixing and allowing to settle.

Why do you need to record the temperature when making careful volume measurements of water?

The density of water depends on its temperature

When describing the uncertainty of a measurement, the term ______ refers to the closeness between measurement and its accepted value, whereas the term _______refers to the closeness among a set of measurements.

acuracy,precision

In order to use a pipet, place a _____ or pump check_circle_outline at the top of the pipet. Use this object to fill the pipet such that the ______ of the liquid is even with the volume line. Release the liquid, touching the tip of the pipet to the side of the container if necessary to release the last drop _____ off the pipet tip.

bulb or pump meniscus outside

Identify the common indicators that a chemical reaction has occurred.

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

Determine whether each property is a physical property or a chemical property. Reactivity Flammability Density Color Solubility Melting point

chemical chemical physical physical physical physical

Determine whether each of the errors listed affects the accuracy of pipets, or can lead to the contamination of pipets. The pipet is not cleaned thoroughly between uses. After the liquid is drained from the pipet, the final drop is pushed through with the pipet bulb. Pipets are washed with detergent and then put to use immediately. The liquid level in a pipet is read from the top of the curve rather than the meniscus. Air bubbles are present as the liquid is drawn up into the pipet and dispensed.

contamination accuracy contamination accuracy accuracy

When using acids and bases, note that these substances are __________. Make every effort to avoid contact with ____________. Be sure to wipe up any spills _______.

corrosive the skin and lab surfaces immediately

Determine whether each of the properties described applies to volumetric or graduated glassware. Capable of measuring a range of volumes of liquid. Used for applications in which great accuracy is needed. Designed to measure one specific volume of liquid

graduated volumetric volumetric

Determine whether each quantity is a measured value or an exact value. 144 grams of sugar 1 ft = 12 in 2 avocados 2 cups of milk 3 teacups 18 meters

measure exact exact measured exact measured

Suppose you mix a solid into water and not all of it dissolves. This is ________ because ____________.

not a sign of a chemical reaction the undissolved solid is not a new substance.

In the presence of an acid, litmus paper appears ___ In the presence of a base, litmus paper appears ____

red blue

A student is likely to make many observations over the course of the lab session. In general, which types of observations are necessary to record in a lab notebook? number of participants in lab at the time of the experiment length of time a substance is heated on a hot plate mass or volume of reagents used color or temperature change of a substance appearance of gas bubbles during a chemical reaction color of the work surface in the lab

shouldn't should should should should shouldn't

Identify the effect on the conductivity measurements if the given errors are made in the lab procedure. The conductivity probe is not rinsed after measuring an electrolyte solution, before measuring a non-electrolyte solution. The conductivity probe is not rinsed after measuring a non-electrolyte solution, before measuring an electrolyte solution. Several drops of an electrolyte solution are spilled out of the vial before a measurement is taken. Tap water rather than distilled water is used to clean the conductivity probe before measurement of a non-electrolyte solution.

too high too low not affected too high

Identify the pieces of glassware that are most effective for accurate solution preparation.

volumetric flask and volumetric pipet