Don't be so dense
When converting density from kg/L to g/mL how do the two numbers compare (i.e., is the density higher or lower number in g/mL compared to kg/L)
What is there is no change?
When separating a mixture with SiO2, NaCl, and NH4Cl, name the first molecule removed and the process for removal
What is NH4Cl and burning until it goes through sublimation
Describe the reaction of SO42- when it is added to H2SO4.
What is no observable reaction (slight temperature increase)
What action can increase the ability of litmus paper to change color?
What is dampening the litmus paper?
Name three unsafe lab practices
What are chewing gum, eating or drinking in the lab, wearing contacts, wearing open toed shoes, not wearing goggles or a lab coat
When calculating the density in an experiment, the solution being used was spilled, causing the mass to be 42.0 mg too low. An appropriate correction to mass measurement was applied and observed density was recalculated. In this case, the experimental error underestimates the mass of the solution. Is this error resulting in an over or under estimate of the observed density
What is an underestimate?
What is an essential step that occurs after each usage of the Bunsen burner?
What is letting the container cool on wire gauze until it reaches room temperature?
How would you distinguish NaCl from NaI
What is use AgNO3 (aq), which forms AgCl (s) which is white but turns purple in light, or forms AgI (s) which is yellow.
Or
What is use H2SO4 (l), if Cl, HCl (g) which smells. If I, dark solid and purple vapors.
What does it mean for a red litmus paper to turn blue?
What is indication of a basic compound
Describe precision
What is how closely individual measurements agree with one another
deviation=|(individual measurement)-(average measurement)|
The temperature of a solution was recorded before carrying out a density experiment with titrations. However, the density of the solution exhibits a strong temperature dependence. (density decreases with increasing temperature). If the experiment was repeated at an increase of 10 degrees Celsius, how would the measurement of the density change?
What is no effect on measured density?
After the separation of a mixture was completed, the experimenter found their mixture was 9% NH4Cl, 17% NaCl, and 68% SiO2. The calculations are correct, what was the mistake in the experiment?
What is some components were lost through human error
Bonus points: what has happened if the mixture components were calculated to total more than 100%?
Write the net ionic reaction for the reaction of a barium ion with a sulfate ion under aqueous conditions
What is
Ba2+(aq)+SO42-(aq)→BaSO4(s)
Name the term for where a solid object is neither floating nor sunk in a known liquid
What is neutral buoyancy?
Describe accuracy
What is how close measurements were with the actual value
error=(average measurement)-(accepted value)
Find mass of a sphere (V=4/3πr3) when the radius is 4.00 cm and the density is 11.45 g/cm3.
Round to the correct number of significant figures
What is 3070 g?
What is the process of pouring a liquid into another container to separate it from a solid?
Bonus 50 points for each:
What is the name of the removed liquid?
What is the name of the remaining solid?
What is a limitation of this process?
What is Decantation?
Bonus:
What is the decantate/decant ?
What is the Residue?
What is some of the liquid is left on the solid?
Write the overall reaction between aqueous HCl and solid Na2CO3 to form sodium chloride, water, and carbon dioxide.
What is 2HCl(aq) + Na2CO3(s) → 2NaCl(aq) + H2O(l) + CO2(g)
Name the equation to find % of a component in a mixture
What is mass component in grams/mass sample in grams multiplied by 100
Describe the steps to find standard deviation in a dataset
What is....
1. find the mean
2. find the difference of each datapoint to the mean (data-mean) and square
3. Find mean of all data points from step 2
4. Take the square root of step 3
A 15.70 g sample of a solid is placed in a graduated cylinder. Toluene, a substance that the solid is insoluble, is added so that the total volume of the solid and liquid is 35.00 mL. The the toluene and solid weigh 37.94 g. The density of toluene at the temperature of the experiment is 0.864 g/mL
What is 1.69 g/mL
(37.94g-15.70g)x (1mL/.864 g)= 22.24/0.864= 25.7 mL
15.70g/(35.00mL-25.7mL)= 15.70g/9.30mL= 1.69 g/mL
How do you separate Benzophenone and naphthol?
What is add cyclohexane to mixture so that Benzophenone dissolves, and filter out naphtol.
Write the overall reaction of concentrated sulfuric acid and solid sodium chloride
What is H2SO4 (l)+ 2NaCl (s) -> 2HCl (g) +Na2SO4?
Describe the steps to find density by the density matching method
What is
1. calibrate your 1 mL syringe (average 3 measurement's volume)
2. Density match solid with concentrated salt solution (~50 mL sodium thiosulfate, record temp, add sample, add 1 mL water with syringe, stir, repeat until sample is in middle of solution (q. 300 LBH))
3. Measure density (take 1 mL and mass, tare, repeat, average, mass/calibrate syringe volume)
Name meaning of one of the 4 colors on a chemical label
Bonus 50 points for every extra meaning named
What is.....
Blue - Health (0-no unusual hazard, 1-may be irritating, 2-may be harmful if inhaled or absorbed, 3-corrosive or toxic, avoid skin contact or inhalation, 4-may be fatal on short exposure, specialized protective equipment required)
Red - Flammability (0-not combustible, 1-combustable if heated, 2-combustable liquid flash point of 100°F to 200°F, 3-flammable liquid flash point below 100°F, 4-Flammable gas or extremely flammable liquid)
Yellow - Reactivity (0-not reactive when mixed with H2O 1-may react if heated or mixed with H2O but not violently, 2-unstable or may react violently if H2O mixed, 3-may be explosive if shocked, heated under confinement, or H2O mixed, 4-explosive material at room temp)
White - specific hazard (corrosive, use no water, acid, alkali, oxidizer, radioactivity)