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Questions in chemistry

[Terjawab] A sample of gas contains $6.25 \times 10^{-3} mol$ in a 500.0 mL flask at $265^{\circ} C$. What is the pressure of the gas in kilopascals? Formula: $P V=n R T(R=8.31 L \cdot kPa / mol \cdot K )$ Which variables are given? pressure volume temperature moles

[Terjawab] What energy is required for a reaction to occur? A. Bond energy B. Potential energy C. Activation energy D. Kinetic energy

[Terjawab] 13. The main reason for performing a back titration instead of a direct titration is: A. The reaction is too slow or weak for direct measurement B. It increases the error in the experiment C. It does not require a burette D. The titration curve is always linear

[Terjawab] Look at the materials listed in the word bank. Tell whether the materials are elements or compounds. Write the materials under the proper columns. Word Bank: Silver Copper Hair spray Mist Water Iron Rust Whipped cream Rubbing alcohol Antiseptic solution | Pure Substances | Mixtures | |---|---| | Element | Compound | Homogeneous | Heterogeneous | | | | | |

[Terjawab] An electric device delivers a current of [tex]$15.0 A$[/tex] for 30 seconds. How many electrons flow through it?

[Terjawab] (1) Write the electronic configuration of an element with atomic mass of 17. (2) What will be the electronic configuration of the following positive charge ions: [tex]$K ^{+}, Cl ^{2+}, Al ^{3+}$[/tex]? (3) What will be the electronic configuration of the following negatively charge ions: [tex]$Cl ^{-}, I ^{-}, Br ^{-}, O ^{2-}$[/tex]?

[Terjawab] Carbon reacts with oxygen to produce carbon dioxide ([tex]CO_2(g), \Delta H_{f }=-393.5 kJ / mol$[/tex]) according to the equation below. [tex]C(s)+2 O_2(g) \rightarrow CO_2(g)$[/tex] What is the enthalpy change of the reaction? Use [tex]\Delta H_{\text {rxn }}=\sum(\Delta H_{\text {f, products }})-\sum(\Delta H_{\text {f, reactants }})$[/tex]. A. -393.5 kJ B. -196.8 kJ C. 196.8 kJ D. 393.5 kJ

[Terjawab] Formulate an investigative question. By the end of this lab, you will determine whether you should add cocoa mix (a solid) before or after heating water (liquid) to make hot chocolate. State a broad question about solubility whose answer would help you determine this.

[Terjawab] Information on hazards associated with a particular solvent can be obtained A. by asking your coworkers B. from the project specifications C. by calling the store where you bought it D. from the SDS for that product

[Terjawab] Directions: 1. Look around your house and find 2 examples of each state of matter: solid, liquid, and gas. 2. List them in the correct column in the table below. 3. Write what you observed that helped you decide the state of matter for each item. | State of Matter | Example from Home | What I Observed | |---|---|---| | Solid | 1. 2. | | | Liquid | 1. 2. | | | Gas | 1. 2. | |