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Questions in chemistry

[Terjawab] Draw and label an example of a mixture you can separate using the methods below. | Method of separation | Example of mixture to separate | |---|---| | sieving | | | filtering | | | using a magnet | |

[Terjawab] Which of the following is described by the equation $H _2 O (t) \rightarrow H _2 O (s)+$ heat? A. Evaporating B. Condensing C. Melting D. Freezing

[Terjawab] Make a table and identify the 3 states of matter (Solid, Liquid, and Gas) found in the following: - In your kitchen - In your living room (sala) - In your bathroom Example: 3 states of Matter in the Kitchen Solid - Liquid - Gas -

[Terjawab] 1. Select the correct option: 1. Which is the symbol of mercury? (a) Cu (b) Hg (c) Au (d) Mg 2. Which of the following is a metal? (a) Nitrogen (b) Oxygen (c) Sodium (d) Carbon 3. Which of the following is the most unreactive metal? (a) Iron (b) Lead (c) Aluminium (d) Gold 4. Which of the following is a soft metal? (a) Sodium (b) Cobalt (c) Magnesium (d) Iron 5. Which of the following is a molecule of compound? (a) Ozone (b) Chlorine (c) Water (d) Hydrogen 6. The positively charged particles in an atom are called (a) neutrons (b) electrons (c) protons (d) none of these 7. Which of the following non-metals is found in a liquid state? (a) Iodine (b) Chlorine (c) Bromine (d) Carbon II. State if the following statements are True or False. Correct the false statement. 1. A molecule is the smallest particle of an element. 2. A pure substance consists of particles of only one kind. 3. Mercury is a non-metal. 4. Water is a compound made up of hydrogen and oxygen gas. 5. Constituents of a mixture are present in a fixed proportion.

[Terjawab] What is the final chemical equation from the following intermediate chemical equations? [tex] \begin{array}{l} P_4 O_6(s) \rightarrow P_4(s)+3 O_2(g) \ P_4(s)+5 O_2(g) \rightarrow P_4 O_{10}(s) \end{array} [/tex]

[Terjawab] Which best describes an element? A. a pure substance B. a type of a mixture C. a pure compound D. an impure substance

[Terjawab] Complete combustion of a 0.350 g sample of a compound in a bomb calorimeter releases 14.0 kJ of heat. The bomb calorimeter has a mass of 1.20 kg and a specific heat of [tex]$3.55 J /\left( g ^{\circ} C \right)$[/tex]. If the initial temperature of the calorimeter is [tex]$22.5^{\circ} C$[/tex], what is its final temperature? Use [tex]$q=m C_p \Delta T$[/tex]. A. [tex]$19.2^{\circ} C$[/tex] B. [tex]$25.8^{\circ} C$[/tex] C. [tex]$34.2^{\circ} C$[/tex] D. [tex]$72.3^{\circ} C$[/tex]

[Terjawab] Which of these is an example of a physical change? A. A banana ripening in the air B. Hydrogen burning in the air C. Zinc reacting with an acid D. Liquid water turning into vapor

[Terjawab] A sample of octane [tex]$\left( C _8 H _{18}\right)$[/tex] that has a mass of 0.750 g is burned in a bomb calorimeter. As a result, the temperature of the calorimeter increases from [tex]$21.0^{\circ} C$[/tex] to [tex]$41.0^{\circ} C$[/tex]. The specific heat of the calorimeter is [tex]$1.50 J /\left( g \cdot{ }^{\circ} C \right)$[/tex], and its mass is 1.00 kg. How much heat is released during the combustion of this sample? Use [tex]$q=m C_p \Delta T$[/tex]. A. 22.5 kJ B. 30.0 kJ C. 31.5 kJ D. 61.5 kJ

[Terjawab] The synthesis reaction to form boron hydride is: [tex]2 B( s )+3 H _2(g) \rightarrow B _2 H _2(g), \Delta H =+36 KJ$[/tex]. What is the enthalpy value for the manipulated reaction: [tex]$1 / 2 B_2 H _2(g) \rightarrow B ( s )+3 / 2 H _2(g)$[/tex] ? A. -18 KJ B. -36 KJ C. +18 KJ D. +72 KJ