ALA3 Zhanming Lin

Sublimation is preferred over recrystallization when you work with an amount of solid material to be purified that weighs: A) at least 1 kg B) about 100 mg C) about 1 mol D) about 1000 ml A OD

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Why is it important to always let hot objects cool before weighing? Convection currents that surround a hot object can interfere with the weighing process. It is safer for people to handle cool objects than hot objects. A plastic weigh boat or weighing paper may be damaged by a very hot sample.

Posttest Direction. Read the questions carefully. Write the letter of the correct answer. 1. Water exists in three states of matter and continuously moving through a cycle on Earth. At which stage in the water cycle does water transform from a gas to a liquid? a.evaporation c. precipitation b. condensation d. Sublimation 2. Carbon dioxide (CO2) forms when coal burns in the presence of oxygen. Which of the following is the BEST evidence that a chemical reaction occurs when the coal burns? a. Production of mechanical energy c. A new substance is produced b. Production of electricity d. Formation of precipitate 3.Which of these does NOT happen during a chemical change? a. New substances are formed with different chemical properties. b. Attractive force between atoms of molecule formed or break. c. The chemical properties of the substances before and after the reaction are the same d. Energy is always released or absorbed. 4. A granular substance is added to a liquid. Which of the…

Arrange the following steps to explain how microwave oven cooks food. Write No.1-4 on the blank provided, 1 as the first step, and 4 is the last.   ___7. As microwaves pass through the food, they transfer energy to the water molecules in the form of heat. This will cook the food.___8. A part of the oven produces microwaves.___9. The microwaves are sent to the reflecting fan.___10. The microwaves are reflected in many directions by the fan and the walls of the microwave oven.​

Recently a team from Clarkson University discovered a porous solid called NU-1000, constructed from Zr, C, O, and H, excels at removing poly- and perfluoroalkyl species (aka PFAS) from water. The density of this material is 0.486 g/cm³ and its surface area is 2255 m²/g. If 50.0 g of this material is placed in water, calculate the total area (in cm²) of this sample. DONT GIVE ANY TYPE OF IMAGE IN ANSWER OTHERWISE I WILL GIVE INCORRECT ANSWER DON'T GIVE HANDWRITTEN SOLUTION

PLEASE double and triple check your answers and help me with all the parts. There are two parts attached as 2 screenshots.

You were asked to watch a video where a small amount of water was placed into a can on a hot plate. After time, it was inverted into ice water. Why did the can implode? Edit View Insert Format Tools Table 12pt v Paragraph v |BIUAv D2

a statement about the scale of plastic production and how this has changed over time using simple lanaguge becsuse it is writte for kids.    a statement about the scale of plastic production and how this has changed over time using complex lanaguge.

What are the differences between crazes vs. cracks in polymer? Can you still use polymeric materials if there are crazes or cracks occurs?

Choose an example of polymorphs. a.graphite and graphine b.diamond and adamant c.pyrite and gold d.graphite and diamond e.galena and halite

In Parts 1 and 2, you noticed some patterns about what kind of substances conduct electricity when dissolved in water, and also how melting points are related.   Let's test this pattern by applying it to other substances. Consider the following substances: Potassium Chloride: KClKClKCl Octadecanol: C18H38OC_{18}H_{38}OC18​H38​O Dimethyl Sulfoxide: C2H6OSC_2H_6OSC2​H6​OS Lithium Bromide: LiBrLiBrLiBr Explain the reasoning that supports your answer.? Use the patterns you saw in the previous sections to predict whether the melting points for each substance will be high (above 400°C) or low (below 200°C).?

calculate the evaporation rate initial temperature at 5 seconds = 26.326 degrees celcius temperature at 30 seconds = 25.046 degrees celcius

Aluminum has a density of 2.7 g/cm3. Suppose you would like to produce a composite material based on aluminum having a density of 1.5 g/cm3. Design a material that would have this density. Would introducing bead of polyethylene, with a density of 0.95 g/cm3, into the aluminum be a likely possibility? Explain.

Which of the following methods is not an appropriate method for purifying a solid under normal laboratory conditions? sublimation Ochromatography distillation recrystallization

Part A One kind of polyester is a condensation copolymer formed between terephthalic acid and ethylene glycol (Figure 1). Draw the structure of the dimer. [Hint: Water (circled) is eliminated when the bond between the monomers forms.] Draw the molecule on the canvas by choosing buttons from the Tools (for bonds and charges), Atoms, and Templates toolbar= gure 206 Terephthalic acid HO–CH,CH, OH Ethylene glycol 1 of 1 050 Δ HD EXP CONT. * Submit Previous Answers Request Answer × Incorrect; Try Again; 5 attempts remaining Part B Complete previous part(s) Provide Feedback H C S CI Br 1