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Questions in chemistry

[Terjawab] A 95.0 g sample of copper $\left( c _y=0.20 J /{ }^{\circ} C \cdot g \right)$ is heated to $82.4^{\circ} C$ and then placed in a container of water $\left(c_y=4.18 J /{ }^{\circ} C \cdot g \right)$ at $22.0^{\circ} C$. The final temperature of the water and the copper is $25.1^{\circ} C$. What was the mass of the water in the original container? Assume that all heat lost by the copper is gained by the water. Use the formulas below to help in your problem-solving. $\begin{aligned} -q_{\text {mas }} & =q_{\text {wate }} \\ -c_m m_m \Delta T_m & =c_w m_v \Delta T_w $\end{aligned}$ A. 0.246 g H _2 O B. 4.73 g H _2 O C. 84.0 g H _2 O D. 36,700 g H _2 O

[Terjawab] How many calories are released when 500 g of water cools from 95.0°C to 25.0°C? A. 4.75 x 104 cal B. 1.25 x 104 cal C. 70.0 cal D. 35.0 cal E. 3.50 x 104 cal

[Terjawab] The table below shows the freezing points of four substances. | Substance | Freezing point (°C) | | --------- | ------------------- | | benzene | 5.50 | | water | 0.00 | | butane | -138 | | nitrogen | -210 | The substances are placed in separate containers at room temperature, and each container is gradually cooled. Which of these substances will solidify before the temperature reaches [tex]$0^{\circ} C$[/tex]? A. benzene B. water C. butane D. nitrogen

[Terjawab] How does the rate law show how concentration changes affect the rate of reaction? A. The rate is expressed as the sum of the concentrations of reactants raised to some power. B. The rate is expressed as the difference between the concentrations of reactants. C. The rate is expressed as a ratio of the concentrations of reactants raised to some power. D. The rate is expressed in terms of concentrations of the reactants raised to some power.

[Terjawab] What is an important science lab safety guideline to remember? Select ALL that apply. A. Clean and return all equipment you used. B. Read all instructions carefully. C. Act responsibly at all times. D. Eat and drink while working in the lab.

[Terjawab] Why will the color of a compressed gas cylinder not tell you anything about the gas inside it? A. Cylinder colors are not standardized. B. Cylinder colors are chosen by the companies that own the cylinders. C. Each cylinder owner may use a different "color-coding" system. D. Both B and C are correct. E. All of the above are correct.

[Terjawab] Empty Space between Particles Aristotle's idea of the continuity of matter implies that all space is filled with matter and that there is no such thing as empty space. This idea is contradicted by the principle of the particle nature of matter, which states that empty space exists between particles of matter. Let us verify this idea by doing Mini Lab 2-1. MINI LAB 2-1 Materials: brown sugar, water, drinking glass, and teaspoon Procedure: 1. Fill the glass halfway with water. 2. Add one-half teaspoon of sugar to the water and stir until it is completely dissolved. Guide Questions: 1. What happened to the sugar and water particles in the solution? What do you think their particle arrangement looks like in the solution? 2. How will you explain your observations in terms of the idea that particles of matter have spaces between them?

[Terjawab] Which best describes solubility? A. the speed at which a substance dissolves B. the ability of one substance to dissolve in another C. the amount of surface area per a given mass D. the temperature at which substances become a mixture

[Terjawab] Which statement correctly compares the pH of water to that of other substances? A. The pH of water increases as its temperature increases, while other substances have a stable pH. B. The pH of water is neutral; it is higher than the pH of acids and lower than the pH of bases. C. Water contains more hydrogen ions than most other substances, giving it a higher pH. D. Water is neutral and has a pH of 0; acids have a pH greater than 0, and bases have a pH less than 0.

[Terjawab] Which of the following factors will slow down the rate of reaction? A. Use as an enzyme B. Increased surface area C. Volume reduction D. Decreased temperature