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Questions in chemistry

[Terjawab] A. Choose the correct option(s) in each. 1. Which among the following is the cleanest fuel? (a) coal (b) petrol (c) diesel (d) CNG 2. Which coal produces the lowest amount of heat? (a) lignite (b) peat (c) anthracite (d) bituminous coal 3. Which of these is an example of a non-renewable resource? (a) trees (b) water (c) coal (d) grass 4. A natural fuel formed from deposits of carbon as plants decomposed millions of years ago. (a) coal (b) petroleum (c) natural gas (d) wood 5. Which of the following is a renewable energy resource? (a) solar (b) methane (c) crude oil (d) coal 6. What is the leading source of energy used in the United States today? (a) coal (b) oil resources (c) natural gas (d) nuclear power 7. Burning of which of the following fuels produces the least amount of carbon dioxide per unit of energy? (a) coal (b) oil (c) natural gas (d) all of these produce the same amount of carbon dioxide 8. Dead organisms are transformed into petroleum and natural gas in (a) absence of air (b) presence of air (c) presence of sunlight (d) none of these 9. Diesel is used in (a) cooking oil (b) paints (c) road surfacing (d) electric generators 10. Which of these is used in extraction of metals? (a) Coke (b) Coal gas (c) Coal tar (d) Petroleum 11. Which of these is used as solvent for dry cleaning? (a) Diesel (b) Kerosene (c) Petrol (d) Paraffin wax 12. The fibres manufactured by petrochemicals are (a) Nylon (b) Polyester (c) Acrylic (d) All of these B. Fill in the blanks: 1. Fuels which are formed by the decomposition of dead plants and animals are called ________. 2. The places where coal deposits are found are called ________.

[Terjawab] In the laboratory, for the preparation of hydrogen gas from granular zinc, why can the following acids not be used? Which is the most suitable for this reaction? a. Conc H2SO4 b. Conc HCl c. HNO3

[Terjawab] Based on the equation and the information in the table, what is the enthalpy of the reaction? [tex]\( \Delta H_{xn}=4619 kJ\)[/tex] [tex]\( \Delta H_{xn}=-46.19 kJ\)[/tex] [tex]\( \Delta H_{rxn}=92.38 kJ\)[/tex] [tex]\( \Delta H_{rxn}=-92.38 kJ\)[/tex]

[Terjawab] Select the correct answer. An ion has a net charge of 3+. If this ion has 8 protons, how many electrons does it have? A. 3 B. 5 C. 7 D. 8 E. 11

[Terjawab] A copper rod that has a mass of 200.0 g has an initial temperature of [tex]$20.0^{\circ} C$[/tex] and is heated to [tex]$40.0^{\circ} C$[/tex]. If [tex]$1,540 J$[/tex] of heat are needed to heat the rod, what is the specific heat of copper? Use [tex]$q=m C_p \Delta T$[/tex]. A. [tex]$0.0130 J /( g { }^{\circ} C )$[/tex] B. [tex]$0.0649 J /( g { }^{\circ} C )$[/tex] C. [tex]$0.193 J /( g { }^{\circ} C )$[/tex] D. [tex]$0.385 J /( g { }^{\circ} C )$[/tex]

[Terjawab] What is the chemical formula of the compound copper(II) phosphate? Use the list of polyatomic ions and the periodic table to help you answer. A. $Cu _3\left( PO _4\right)$ B. $Cu \left( PO _3\right)_2$ C. $Cu _2\left( PO _4\right)_2$ D. $Cu _3\left( PO _4\right)_2$

[Terjawab] Radhika has four beakers, and each beaker contains 100 ml of acidic solution. The amount of acid in each beaker is given below. Beaker 1 - 50 ml of acid Beaker 2 - 25 ml of acid Beaker 3 - 80 ml of acid Beaker 4 - 75 ml of acid Arrange these solutions in the order of their concentration, starting from the most diluted.

[Terjawab] What are the substances you end up with in a chemical reaction called? A. The reactants B. The products C. The resultants D. The solution

[Terjawab] Ammonia $\left( NH _3(g), \Delta H_{ f }=-46.19 kJ / mol \right)$ reacts with hydrogen chloride $\left( HCl ( g ), \Delta H_{ f }=-92.30 kJ / mol \right)$ to form ammonium chloride ( $NH _4 Cl ( s ), \Delta H_{ f }=-314.4 kJ / mol$ ) according to this equation: $NH_3(g)+HCl(g) \rightarrow NH_4 Cl(s)$ What is $\Delta H_{ rxn }$ for this reaction?

[Terjawab] Classify the following substances into elements and compounds. Elements: Silver Oxygen Iron Carbon Compounds: Salt Hydrogen chloride Water Sodium bicarbonate Hydrogen iodide Gold