Chemistry 305 Exam II (practice) Chp 4-6

1. Suppose you want to know the formula of a hydrate of barium thiocyanate. If you heat 1.089 g of the hydrate until all of the water is vaporized, the mass of anhydrous Ba(SCN)2 is 0.898 g. What is the formula of the hydrate, i.e. what is the value of x in Ba(SCN)₂.xH₂O? (The formula weight of anhydrous barium thiocyanate is 253.49 g/mol)

Some salts make hydrates when there is moisture around. Some hydrate samples can absorb lights in visible legion. Therefore, they show some colors. Thus, hydrates can be used to detect the moisture in the environment. Let's say you are working in a laboratory with a group and you are the only student who has taken chemistry courses. Your laboratory received a sample of cobalt(iI) chloride which has the formula CoCl2xH20. Let's say your boss asked you to find the formula of this hydrate salt sample since you are the only chemist there. From your laboratory experience, simply explain the experimental procedure you would follow to find the formula of this unknown sample. Then, use the given data for the calculation part. Mass of crucible: 32.27g Mass of crucible + unknown hydrate: 33.92 g Color of unknown hydrate: purple Mass of crucible + anhydrous form of hydrate: 33.41 g Color of anhydrous form: sky blue

Unit Activity: Chemical Bonding Question 3 Will magnesium and fluorine atoms most likely form an ionic bond or a covalent bond? I X, Font Sizes = E 星E 三 ヨ Characters used: 0/15000 Question 4 Write the name and formula of the compound made of magnesium and fluorine. Font Sizes 三 E 三三 !!!

(c) Argon d) Fluorine 6. The number of nonmetal atoms in Al2(SO4)3 (a) 2 15 (b) (c) 12 (d) 8 7. Which of the following properties of water is not a (a) Water normally boils at 100°C

Q4. Thinking of the individual charges of the metal and polyatomic ions present in Ca5(PO4)3OH, can you explain why this compound is neutral? Show the working of how the charges balance each other out. (3)

Predict the chemical formula for a compound composed of Na+ and S2- and give the appropriate name.

Write the chemical formula for this molecule: Drag the slider to get a different view of the molecule. 11 X ●carbon nitrogen oxygen fluorine ? key O hydrogen O sulfur Ochlorine bromine

- Classify each compound as ionic or molecular. If it is ionic, determine whether the metal forms only one type of ion or more than one type of ion. (a) CoCl2 (b) CF4 (c) BaSO4 (d) NO

Explaining to me in great detail how to name Sr(OH)2 and Fe(OH)3 compounds. What type of compounds are they? What are the charges on the metals? How are the nomenclature rules different for these two compounds?

2 (S 18 PERIMENT D Flame Tests: Which lon Causes the Color? Part A: Laboratory Results Summarize your laboratory results in the following data table after examining the color of the flame. Complete the table by filling in the flame test color and the missing chemical formulas, and ions (cation and/or anion). MATERIAL/COMPOUND TESTED Sodium Chloride NaCl Sodium Carbonate Strontium Acetate Copper (II) Sulfate Lithium Carbonate Potassium Sulfate Sodium Phosphate Barium Nitrate CATION PRESENT ANION PRESENT Na¹+ Na¹+ Sr2+ ㅎ CIT- CO3²- C₂H30₂¹- SO4²- CO3²- SO4²- PO4³- NO 3¹- Data detailed FLAME TEST COLOR orange greenish with a spark of crange Orange with a sparn в purple oraine outler spergi be sparvo of crange red with crant with still be due fame affranks ready bottarg Orange that arany -sparks up on greenish reatly no change oranze purple, at first a little thi turned back blue notice green crange Purple, peach red at top bright arany blue at botter Blue, Crans green Jumped different Did…

3. How many valence electrons are in a C atom? an Cl atom? (a) Write the full Lewis structure for the CH2C2 molecule. Show all lone pairs. Pert (b) Write the geometric structure for the CH2CI2 molecule and name the geometry. (c) Determine if the CH2CI2 molecule has polar or nonpolar bonds using the following electronegativity: C = 2.5, H = 2.1, CI = 3.0. Re-draw the geometric structure below, but this time include partial charges and dipole arrows for any polar bonds present. Justify your assignments for polar or nonpolar bonds.

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Cesium bromide crystallizes in a cubic unit cell with Br ions at the corners and a Cs ion in the center. The edge length of a CsBr unit cell is 436.9 pm.

7. Balance the following equations: a) For the synthesis of urea, a common fertilizer CO2(g) + NH3(g) → NH₂CONH2(s) + H2₂0 (1)

A fictional compound contains three elements.  Here's what you know: Hydrogen (H): proton can be removed by water Alchemium (X): a nonmetal X forms a polyatomic ion with oxygen (O): the "-ate" form of the ion has the formula XO33- The chemical formula of the compound is H3XO A. Is this an ionic compound, a covalent compound, or an acid? B. What would the chemical name of this compound be?

Chemistry

Flake white was a white pigment used by Renaissance artists, which was composed of a combination of lead(II) carbonate and lead(II) hydroxide. What are the correct chemical formulas for these two compounds?

Consider the following elements in their stable forms: Chlorine Fluorine Bromine Carbon Then for each of the following questions, enter the number listed (1-4) before the element, for elements that satisfy the criterion. Enter the number(s) in order with no separators. If none, type "none" or leave blank. (a) Which of these elements have allotropes? fill in the blank 2d8840092ffc02e_1 (b) Which of these elements exist as diatomic molecules? fill in the blank 2d8840092ffc02e_2 (c) Which of these elements exist as a metallic lattice?

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Answer the following question