Chemistry Questions

Can y'all give me some examples of physical changes
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How does a balanced chemical equation show that mass is never lost or gained in a chemical reaction
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1. A tuning fork has a frequency of 280 hertz, and the wavelength of the sound produced is 1.5 meters. Calculate the velocity of the wave. - Answer: 2. A wave is moving toward shore with a velocity of 5.0 m/s. If its frequency is 2.5 hertz, what is the wavelength?- Answer: 3. A jump rope is shaken producing a wave with a wavelength of 0.5 m. with the crest of the wave passing a certain point 7 times per second. What is the velocity of the wave?- Answer: 4. The lowest pitch that the average human can hear has a frequency of 20.0 Hz. If sound with this frequency travels through air with a speed of 331 m/s, what is its wavelength? - Answer: 5. A microwave has a frequency of 4,255 Hz. and a wavelength of 0.05 m. What is the microwave’s velocity?- Answer: 6. A sound wave travels with a velocity of 460 m/s and has a frequency of 820 Hz. What is its wavelength?- Answer: 7. A wave at sea travels with a velocity of 32 m/s. If it has a wavelength of 8 m. what is its frequency?- Answer: 8. What is the frequency of a wave that has a velocity of 21.3 m/s and a wavelength of 7.8 m?- Answer:
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O2 +C8H18--> H2O + CO2
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Which material is not a form of pyroclastic material?A- volcanic dustB- volcanic dirtC- volcanic bombsD- lapilli
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Unscramble the letters RIVAENG, it's the name of a liquid.
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Which is an example of an atom?A)the smallest unit of NeB)the smallest unit of p4C)the smallest unit of NH3D)the smallest unit of H2O
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Describe the structure of an atom. A)The nucleus is the dense center of the atom composed of protons and neutrons. Surrounding the nucleus is an electron cloud composed of electrons. B)The nucleus is the dense center of the atom composed of electrons and neutrons. Surrounding the nucleus is an electron cloud composed of protons. C)The electron cloud is the dense center of the atom composed of electrons. Surrounding the electron cloud is a nucleus composed of protons and neutrons. Eliminate D)The electron cloud is the dense center of the atom composed of protons and neutrons. Surrounding the electron cloud is a nucleus composed of electrons.
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Are these answers correct?1. A gas occupies 30 L at 760 mm Hg. What is its volume at 350 mm Hg? P1*V1 = P2*V2 760 mm Hg *30 L = 350 mm Hg * V2V2 = 22800 mm Hg*L/350 mm HgV2 = about 65.14 L2. A gas occupies 500 mL at 1 atm. What is its pressure if the volume becomes 1500 mL?P1*V1 = P2*V21 atm*500 mL = P2*1500 mL500 atm*mL/1500 mL = P2P2 = 1/3 atm3. If a gas occupies 250 mL at 25°C, what will its volume be at 57°C? 25°C + 273 = 298°K; 57°C + 273 = 330°KV1/T1 = V2/T2250 mL/298°K = V2/330°K0.84 mL/k*330°K = V2V2 = about 276.85 mL4. What was the original temperature of a 2 L sample of gas if it initially had the volume 5 L at 27°C? 27°C + 273 = 298°KV1/T1 = V2/T25 L/298°K = 2 L/T22 L/(0.017 L/K)= T2T2 = 119.2°K = -153.8°C 5. At what pressure would 100 mL of a gas be found if it began at 500 mL at 2.5 atm?P1*V1 = P2*V2 2.5 atm*500 mL = P2*100 mL125 atm*mL/100 mL = P2P2 = 1.25 atm6. What is the volume of a gas at 275 mm Hg if it occupied 750 mL at 1000 mm Hg?P1*V1 = P2*V21000 mm Hg*750 mL = 275 mm Hg*V2750000 mm Hg*mL/275 mm Hg = V2V2 = about 2727. 27 mL7. A gas occupies 60 L at 250°K and 1 atm. What is its volume at 250°C and 1.5 atm?250°C + 273 = 523°KP1*V1/T1 = P2*V2/T21 atm*60 L/250°K = 1.5 atm*V2/523°K0.24 (atm*L/K)*523°K = 1.5 atm*V2125.52 (atm*L)/1.5 atm = V2V2 = 83.68 L8. What is the final temperature in Celsius of a gas occupying 3.25 L at 750 mm Hg if it occupied 2250 mL at 37°C and 600 mm Hg? 37°C + 273 = 310°K; 2250 mL = 2.25 LP1*V1/T1 = P2*V2/T2600 mm Hg*2.25 L/310°K = 750 mm Hg*3.25 L/T22437.35 mm Hg*L/ (4.35 mm Hg*L/K) = T2T2 = 559.69°KT2 = about 286.69°C
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How is the water supply for New York being protected?
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Can someone please help me?
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Why is the radius of a positive ion always less than the radius of its neutral atom? (A) the nucleus pulls the remaining electrons in closer.(B) The number of principal energy levels is always reduced. (C) The atomic orbitals contract all by themselves (D) Electron speeds are reduced
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Which of the following is a solution: pure water, fruit punch, cereal and milk in a bowl? Explain how you know.
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What is the name of a neutral group of atoms that are held together by covalent bond (this word has 8 letters)
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What takes place among elements to form an ionic bond? A.One or more electrons are transferred.B.One or more electron shells are shared.C.One or more electrons are shared.D.One or more electron shells are transferred.
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List and describe two powerful forces of nature caused by plate tectonics
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Which of the following is an example of a homogeneous mixture? A. BronzeB. SandC. CopperD. Zinc
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Water is densest at 4°C. What is that temperature on the Kelvin scale?
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