Science homework help ??? (: 5 multiple choice questions!?
1.What happens to energy during a chemical reaction? a.)Energy is created by the chemical reaction. b.)Energy is burned up by the chemical reaction. c.)Energy is converted from one form to another. d.)Energy is used up by the chemical reaction. 2.What is true about the energy involved in a chemical reaction? a.)The amount of energy is constant, but it is converted from one form to another. b.)The amount of energy decreases as it is converted from one form to another. c.)The amount of energy increases as it is converted from one form to another. d.)The amount of energy may increase or decrease depending on the type of reaction. 3.Why is mass conserved in a chemical change? a.)The energy used in the chemical reaction burns up the extra matter. b.)The compounds are still exactly the same, they just look different. c.)The atoms are still there, they are just rearranged to form new compounds. d.)The new matter that is formed takes up the same volume as the original matter. 4.What is always conserved in a chemical reaction? a.)Mass is always conserved in a reaction. b.)Energy is always conserved in a reaction. c.)Mass and energy are both conserved. d.)Nothing is always conserved in a reaction. 5.When sodium and oxygen react to form an ionic compound, the mass of the compound ____ the sum of the masses of the individual elements. a.)is less than b.)is greater than c.)is equal to d.)can be greater than or less than
Chem Homework Help. Multiple Choice?
When one atom of carbon (C) combines with four atoms of hydrogen (H), four nonpolar covalent bonds form, resulting in a molecule of methane (CH4). Which of the following describes the arrangement of valence electrons in a bond between C and H? (2 points) a. The valence electrons are shared equally between C and H. b. The valence electrons spend more time around the atom of C. c. The valence electrons spend more time around the atom of H. d. The valence electrons are given up by the H and gained by the C. Which of the following would you expect to form an ionic bond when combined? (2 points) a. Si and O b. K and Ti c. H and O d. Li and F What is the formula of a compound formed between phosphorus (P) and barium (Ba)? (2 points) a. P3Ba2 b. P2Ba3 c. Ba3P2 d. Ba2P3 Which of the following is not a correct formula unit? (2 points) a. K2O b. MgO2 c. Al2O3 d. SrO When electrons are transferred between atoms so that stable electron configurations are achieved, the resultant bonding forces are (2 points) a. ionic. b. covalent. c. hydrogen. d. very weak
Homework; Cells, biology help! read question! multiple choice! Help?
Question, After a cell was treated with a certain chemical, the ribosomes stopped functioning. Which cell activity was immediately affected by this change in ribosome function? A) Intracellular transport B) Protein synthesis C) Excretion of metabolic wastes D) Aerobic respiration no stupid answers please! I have to get this stupid study guide RIGHT, and finished, so I can go out for my Valentine's Day dinner... please :( I'm desperate
Chemistry homework (easy) (multiple choice)?
Hi, I have answered all the questions on my homework; the ones I'm posting are the ones im not sure of, just thought i'd let you know ur not doing it for me. 1)A substance that can't be broken down into simpler substances is A) Heterogenous mixture B) Homogeneous mixture C) compund Delectron E)an element...... It's probably A, or E idk 3) Chose the Heterogeneous mix A) Carbon B) Gatorade C_chicken noodle soup D)Cholrine E) Black Cofee 9) Example of physical change A) hydrogen balloon explodes when contact with flame Bhalloween light stick glows after shaking C)an egg solidifies during cooking D)Dew forms on a blade of grass E)None of the above 10)which answer with correct significant figurs is (433.621 - 333.9) x 11.900 A)1.19x10^3 B)1.87x10^3 C) 1.1868x10^3 D)1.8680x10^3 E)1.186799X10^3 25)which of the following are examples of extensive propiertie? A)Mass B)Color C)Taste D)Density E)Temperature 28)what wavelenght of light would you report in units of nm, if the light had a wavelenght of 7.60x10^-10m?? A)7.60x10^-3nm B)760nm C)7.60x10^-19nm D)1.32nm E)0.760nm
Help with chemistry homework?
To correct my fellow Yahoo Answers friend, Dhruv, I respectfully list the correct answers from 9 years of undergrad, graduate, and post graduate work (though any senior in high school SHOULD know this...): 1. not created or destroyed. CORRECT 2. Amount of matter in an object CORRECT 3. As temperature increases, the molecules and atoms move faster. CORRECT (answer is more complex) 4. volume. CORRECT 5.pot of water on a stove INCORRECT! 6.graduated cylinder CORRECT (although you could use a scale as well if you used Archimedes' method.) 7. gravitational energy INCORRECT! 8. The cork is less dense than the water. CORRECT 9. Thermal energy is converted to electrical energy. INCORRECT! 10. the effect of gravity on an object CORRECT Correct answers: 5. X-Ray Why? Radiant energy is referring to electromagnetic radiation (waves-particle duality). The only item listed that is on the EM spectrum is an X-ray. 7. Thermal Energy. Why? Gravitational, chemical, and nuclear energy all refer to types of POTENTIAL ENERGY. Thermal energy is a defined as the energy of the matter contained in any system. Under this understanding, thermal energy can NEVER be POTENTIAL, it is always kinetic except at absolute zero when thermal energy ceases to be extant. 9. Radiant energy is converted to electrical energy. Why? Radiant energy, as discussed earlier is the energy of EM radiation. Solar cells and panels use light, specific frequencies depending on the material used in the gap construction, to form a temporary electron bridge. This flow of electrons is electricity, i.e. electrical energy. While some derivations exist that utilize non-photovoltaic solar panels to heat a medium and produce electricity, the solar panels being referenced here are using the photovoltaic effect. (Trust me, I checked the questions pedagogical intent against the instructor's guide in your text's test bank. After writing the answers, I verified them against the answer key.)
Quick Chem Multiple Choice Question -- 10 Points!?
Hi, I am doing a chemistry homework sheet and I am stuck. The homework is graded so I am worrying a lot and pondering each question greatly. I included the question and the 4 multiple choice answers. How is VSEPR theory used to classify molecules? 1. Shapes of molecules are based only on the number of different angles around a molecule's central atom. 2. Shapes of molecules are based on the number of bonding electron pairs and lone pairs that surround a molecule's central atom. 3. Shapes of molecules are based only on the number of bonding electron pairs that surround a molecule's central atom. 4. Shapes of molecules are based only on the number of lone pairs that surround a molecule's central atom. Thanks a lot for all the help. 10 points will be given for the correct answer.
Chemical energy physics multiple choice.?
Hi! The answer is C, All examples involve chemical energy except coasting downhill on a bike. In (a) glucose from the body along with the oxygen we breathe is converted into carbon dioxide and water through a chemical process In (b) the hydrocarbon which te candle is made of is combusted into carbon dioxide and water. Combustion is a chemical process Thanks, Hope this helps! :-)
Science homework help please?
1.) bike rusting 2.) A physical change does not change the identity of the substance but the chemical change does 3.) Water evaporating 4.) chemical change. 5.) physical change. 6.) where chemical bonds are broken and new bonds are formed. 7.) chemical change. 8.) Mass is gained. 9.) do not change the identity of the substance. 10.) Freezing ice Remember - Chemical changes: involve breaking and making new bonds (usually result in the formation of a new substance/change of identity) physical changes - the transition of a substances from solid, liquid and gas and the identity of the substance is the same. a phase change is just the transition of a physical sate to another. oh, by the way, apparently some of the questions have 2 answers and I hope you go and ask your teacher to go through it with you again to actually understand it.
Homework help again =] thanks?
another math question.. On the first day of a sale, a camera was reduced by $8. This represented 10% of the original price. On the last day of sale, the camera was sold for 75% of the original price. What was the final selling price of the camera? can u explain your answer please.. thanks a lot