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Questions in chemistry

[Terjawab] What is the theoretical phenolphthalein alkalinity of a saturated solution of Ca(OH)2?

[Terjawab] What is the pOH of a solution with [tex]$\left[ OH ^{-}\right]=1.4 \times 10^{-13} ?[/tex] A. 13.15 B. 12.85 C. -13.15 D. 14.00

[Terjawab] How do chemical properties differ from physical properties?

[Terjawab] 8. What chemical reaction occurs when iron reacts with oxygen and moisture in the air? A. Formation of aluminum oxide B. Rusting C. Release of carbon dioxide 9. Which material is considered biodegradable? A. Plastic drinking straw B. Nylon fishing line C. Banana peel 10. What happens to a banana peel when it is discarded in a natural environment? A. It remains unchanged B. It decomposes into simpler organic compounds C. It reacts with other materials to form new substances D. It breaks down into smaller pieces

[Terjawab] The half-life of a particular radioactive substance is 5 months. If you started with 100 grams of this substance, how much of it would remain after 10 months? Remaining Amount $= I (1-r)^{ t }$ [?] grams Round your answer to the nearest whole number.

[Terjawab] Activity No. 1: Observing the Shape of Solids, Liquids, and Gases Objective: (a) Describe the properties of solids, liquids, and gases in terms of shape. (b) Differentiate the distinct shapes exhibited by the three states of matter: solid, liquid, and gas through hands-on exploration and observation. Materials Needed: - Stone - Water - Three balloons Instructions: 1. Gather and work in groups. 2. Together with your classmates, perform the activity. Procedure: 1. Put the stone into one balloon and tie the top of the balloon. 2. Fill another balloon with water and tie it. 3. Blow up the third balloon with air and tie it. 4. Press the stone, water, and air in the three balloons and observe the changes in shape. Based on your observations, answer the following questions: - What happened to the shape of the stone when you pressed it? - What happened to the shape of the gas and liquid when you pressed them?

[Terjawab] The molar mass of calcium chloride ($CaCl_2$) is $110.98 g/mol$. If you were to calculate the number of moles in 23.4 g of $CaCl_2$, which example shows the correct way to set up the calculation? A. $23.4 g CaCl_2 \times \frac{110.98 g CaCl_2}{1 mole CaCl}$ B. $23.4 g CaCl_2 \times \frac{1 mole CaCl_2}{110.98 g CaCl_2}$

[Terjawab] Which of the following is a balanced equation representing the decomposition of lead(IV) oxide? A. [tex]2 PbO \longrightarrow 2 Pb+ O _2[/tex] B. [tex]PbO \longrightarrow Pb + O[/tex] C. [tex]PbO \rightarrow--> Pb + O _2[/tex] D. [tex]PbO _2 \rightarrow Pb+ O _2[/tex]

[Terjawab] How many grams of HCl are needed to make 200.0 mL of a 3.0 M solution? HCI: 36.46 g/mol

[Terjawab] Consider the reaction [tex]H _2(g)+ I _2(g) \Leftrightarrow 2 HI ( g )[/tex]. What is the reaction quotient, [tex]Q[/tex], for this system when [tex][ H _2]=0.100 M[/tex], [tex][ I _2]=0.200 M[/tex], and [tex][ HI ]=3.50 M[/tex]?