“Models are developed when a scientist’s creativity and insight are combined with data and observations about many similar scenarios”. Models are used for a lot of things in science. As we know everything has advantages and disadvantages, and the same applies to models. Models help us illustrate the concept and formulate hypothesis. When models are used, the scientists are able to notice patterns and develop and revise representation that become a useful model, which makes their scientific knowledge stronger and helps them understand more about the nature of science. Models are a simplified representation. One of the biggest advantages of the model is, that it allows you to have a look at things which are too small such as atoms or too big such as the solar system.
Although, having many benefits, models have quite a number of disadvantages. Models sometimes oversimplify the process therefore leading to a misunderstanding. As models are supposed to be a simplified representation, they will not be complex, which means they will lack detail. For Example “our particle model explains many things about matter, it is not comprehensive — for example, it cannot predict why certain materials have different electrical properties. We could add further refinements that are outside the scope of this course to enable it to do so, but it would make our model so complicated that it would no longer be useful to us”
Neon is an example of a(n): A. Alkali Metal B. Noble Gas C. Halogen D. Rare Earth Metal
1. Which graph shows the melting of crystalline solids? Explain your reasoning.
2. What type of solid does the other graph show? Explain.
compounds with high melting points have _____
A.covalent bonds
B. metallic bonds
C. ionic bonds
D. no chemical bonds
Answer:
C) Ionic bonds
Explanation:
The ionic bonds are the strongest bond, it occurs when a metal donates electrons and a nonmetal gain these electrons. They'll be together by electrostatic force.
Metallic bonds it the second strongest bond, it occurs between metals, which loses electrons. It's an electrostatic force, but weaker than the ionic compound because it occurs between the cation and the electron.
Covalent bonds are the weakest bond. It happens between metals and nonmetals, or nonmetals and hydrogen or between atoms of hydrogen. The force that joins the atoms depends on the polarity of the molecule. Polar molecules have dipole forces, nonpolar molecules, induced dipole forces. Also, hydrogen makes special dipole forces with nitrogen, oxygen, and fluorine, called hydrogen bond.
As the stronger is the force, as difficult it will be to break it. So, ionic bonds will demand more energy to become gas, and have high melting points.
Compounds with high melting points have [tex]\boxed{{\text{C}}{\text{. ionic bonds}}}[/tex].
Further Explanation:
The attraction between different atoms, molecules and ions is known as a chemical bond. Such bonds are responsible for the formation of chemical compounds.
Ionic bond
It is formed by the interaction of a metal with a non-metal. Metals are electropositive in nature so they have the tendency to lose electrons whereas non-metals tend to gain electrons due to their high electronegativity. Metal atoms form cations by loss of electrons and non-metals become anions with the gain of electrons.
Covalent bond
It is formed by the mutual sharing of electrons between the bonded atoms. It is also known as a molecular bond. Such bonds usually exist between two or more non-metals.
Metallic bonds
These are formed between metal atoms and metallic solids are produced. These are good conductors of electricity due to the presence of delocalized electrons. Copper, gold, zinc are examples of metallic solids.
An ionic bond is the strongest bond, followed by metallic bond and covalent bond is the weakest among the three given bonds. A large amount of energy is required to break ionic bonds as compared to the other two bonds so compounds with ionic bonds have high melting points. Therefore option C is correct.
Learn more:
Identification of ionic bonding: https://brainly.com/question/1603987 What type of bond exists between phosphorus and chlorine? https://brainly.com/question/81715Answer details:
Grade: High School
Subject: Chemistry
Chapter: Ionic and covalent compounds
Keywords: chemical bond, melting points, metallic bond, ionic bond, covalent compound, interactions, metals, nonmetals, cations, anions, mutual sharing of electrons.
When two liquids are combined and form a solid (but didn't freeze) the solid that was formed is called
science question down below hurry
Question 1: Define the terms hypothesis, independent variable, dependent variable, and a controlled variable in your own words.
Question 2: We discussed the importance of having only one independent variable, but trying to test more than one independent variable is an error many people make. In the following experiment, identify the errors that the experimenter made and summarize a valid way to test his research question: What cooking spray best keeps food from sticking to a pan? In the morning, Dan uses grapeseed oil to cook eggs for breakfast; for lunch, he uses vegetable oil spray to coat a muffin tray and cooks cornbread to eat with his chili; for dinner, he uses olive oil to pan cook a hamburger patty.
please help
balance this equation
Cu(NO3)2➡️CuO+NO2+O2
Final answer:
The balanced chemical equation for the decomposition of copper(II) nitrate into copper(II) oxide, nitrogen dioxide, and oxygen is 2 Cu(NO3)2 ➔ 2 CuO + 4 NO2 + O2. This illustrates the conservation of mass by ensuring equal numbers of each type of atom on both sides of the equation.
Explanation:
The question you've asked pertains to balancing the chemical equation Cu(NO3)2 ➔ CuO + NO2 + O2. This process involves ensuring that the number of atoms for each element is the same on both sides of the equation.
To balance this equation, we start with the given substances and adjust the coefficients (the numbers in front of the chemical formulas) to make sure the atoms are balanced. After several steps of balancing, we arrive at the balanced equation:
2 Cu(NO3)2 ➔ 2 CuO + 4 NO2 + O2
This equation indicates that 2 moles of copper(II) nitrate decompose to form 2 moles of copper(II) oxide, 4 moles of nitrogen dioxide, and 1 mole of oxygen gas. The balancing process takes into account the conservation of mass, which states that atoms are neither created nor destroyed in a chemical reaction.
Hair color is a trait that’s controlled by many genes working together. Each gene contributes to this trait only in a small proportion. Which pattern of inheritance is this?
why do you think different liquids have different freezing points
when a star dies which of these celestial objects is it most likely to help create ?
1 a planet
2 a star
3 a moon
4 a meteor
5 a comet
The correct answer is option 2, that is, a star.
Stars die as they consume all the fuel, which permits a star to go through the process of fusion. A star is formed majorly of helium and hydrogen. Once a star uses all the hydrogen, the star begins to die. When a normal-sized star dies, the core eventually cools into a white dwarf, and then into a black dwarf.
White dwarf refers to a very dense and small star, which is usually of the size of a planet. A white dwarf is produced when a low-mass star has used all its central nuclear fuel and lost its outer enveloping as a planetary nebula.
A student dissolved a sample in hexane, spotted it on to a TLC plate and eluted using ethyl acetate. After visualizing the TLC plate under a UV lamp, the student found their sample had two spots corresponding to Rf values of 0.31 and 0.85. They ran the TLC plate again, this time dissolving the compound in dicholoroacetic acid and using ethyl acetate as the eluent. What will be the Rf values for each spot?
1) Consider the following silica gel TLC plate of compounds A, B, and C developed in hexanes:
Determine the Rf values of compounds A, B, and C run on a silica gel TLC plate using hexanes as the solvent.Which compound, A, B, or C, is the most polar?What would you expect to happen to the Rf values if you used acetone instead of hexanes as the eluting solvent?How would the Rf values change if eluted with hexanes using an alumina TLC plate?Show answer
2) You are trying to determine a TLC solvent system which will separate the compounds X, Y, and Z. You ran the compounds on a TLC plate using hexanes/ethyl acetate 95:5 as the eluting solvent and obtained the chromatogram below. How could you change the solvent system to give better separation of these three compounds?
Show answer
3) After a rather lengthy organic chemistry synthesis procedure, a student ran the product of the reaction on a TLC plate and obtained the result below. What might he/she have done wrong, if anything?
Show answer
4) A student spots an unknown sample on a TLC plate. After developing in hexanes/ethyl acetate 50:50, he/she saw a single spot with an Rf of 0.55. Does this indicate that the unknown material is a pure compound? What can be done to verify the purity of the sample?
Show answer
5) Consider a sample that is a mixture composed of biphenyl, benzoic acid, and benzyl alcohol. The sample is spotted on a TLC plate and developed in a hexanes/ethyl acetate solvent mixture. Predict the relative Rf values for the three compounds in the sample.
Show answer
6) Plate A, below, represents the TLC chromatogram of a compound run in hexanes. The same compound was then spotted on a large TLC plate and again run in hexanes. Which TLC plate, B, C, or D, correctly represents how far the compound would run on the longer plate?
Show answer
Back to TLC
Original content © University of Colorado at Boulder, Department of Chemistry and Biochemistry.compounds with ____ bonds are poor conductors of electricity, even when melted.
Answer is: covalent.
Covalent compound (for example methane) are usually bad electricity and heat conductors, because molecules aren far from each other, so heat transfer is less efficient.
They do not form ions and atoms are less positive and negative than in ionic compounds.
Ionic compounds are good good electricity and heat conductors, because ionic compounds (for example sodium chloride NaCl) have mobile ions (cations and anions) that are able to transfer electrical charge. This compounds also conduct heat, because the ions are next to each other, so energy can be transferred efficiently from one place to another.
Which method would be best to separate a mixture of oil and vinegar?
1. Which graph shows the melting of crystalline solids? Explain your reasoning.
2. What type of solid does the other graph show? Explain.
In which biome are you likely to find an organism that has a white coat in winter and a light brown coat in summer? A. desert B. coniferous forest C. tropical rainforest D. savanna
Answer: B. Coniferous forests
Explanation:
The coniferous forests are found in regions of Siberia and Canada. These forests exhibit climatic conditions which range from extremely cold winters, mild to extremely hot summers. Thus the living beings in these forests exhibit adaptations. The organisms which are in brown coat acquire a trait of white coat in winters due to adaptation. It helps the organism to remain insulated and mimic the color of the snow so that the organism remain hidden from the predators.
I am a cold planet on the surface but hot at my core. There are 11 rings that circle me. You will find 21 moons in orbit around me. I rotate on my side. Which planet am I? A.
Pluto
B.
Jupiter
C.
Saturn
D.
Uranus
What happens to the sample's reported water content if the salt decomposes yielding a volatile product?
The decomposition of salt yielding a volatile product can increase the reported water content of a sample in volatilization gravimetry, due to the attribution of the mass loss of the volatile product to water content.
When a sample's salt decomposes, yielding a volatile product, the reported water content of the sample can be affected. In volatilization gravimetry, the sample undergoes thermal or chemical decomposition, which leads to a change in mass resultant from the loss of volatile material. If the decomposition of the salt generates a volatile product, such as water vapor, this will lead to an erroneously high water content measurement since the volatile product is included in the total mass loss that is attributed to water content.
The temperatures used in drying the sample affect the results. Drying the sample at a lower temperature (103-105°C) could result in the retention of some occluded water, whereas drying at a higher temperature (180°C) may release occluded water but also cause a greater loss of substances like carbonates. If salts like chlorides and nitrates decompose, they may form volatile products that could escape, thereby falsely increasing the measurement of the water content.
To ensure accurate evaluations, it's essential to understand the decomposition products and use specialized equipment to trap and weigh any volatile products. This allows for a more precise measurement of the true water content of the sample.
how are the empirical and molecular formulas for a compound related?
A student conducted an experiment to test whether talking to plants would help them to grow faster. The student talked to one group of plants and hand watered them. The student did not talk to the other group of plants and used sprinklers. After three weeks, the plants that were spoken to showed much more growth than the plants that were not. Based on the results of this experiment, which is the best conclusion? Talking to plants may or may not help plants grow faster because three weeks is not enough time to tell. Talking to plants may or may not help plants grow faster because the amount of water given was likely different for each group. Talking to plants does not help plants grow faster because the experiment did not involve enough groups of plants to determine this. Talking to plants does help plants grow faster because those plants showed more growth.
Answer is: Talking to plants may or may not help plants grow faster because the amount of water given was likely different for each group.
The scientific method is a process for experimentation that is used to explore observations.
Steps of the scientific method:
1) ask a question about something that is observed.
2) do background research. It this ecample, research is not good enough, because there are teo variables (talking to plants and amount of water).
3) construct a hypothesis, an attempt to answer questions with an explanation that can be tested.
4) test of hypothesis.
5) analyze collected data and draw a conclusion.
What is the balanced net precipitation reaction for BaCl2 and KOH?
Final answer:
The balanced net precipitation reaction for BaCl₂ and KOH results in solid barium hydroxide and potassium chloride in solution, with the net ionic equation being Ba²⁺(aq) + 2OH⁻(aq) → Ba(OH)₂(s)
The balanced net precipitation reaction between aqueous barium chloride (BaCl2) and potassium hydroxide (KOH) involves a double displacement reaction where the cation of one reactant (Ba2+ from BaCl2) combines with the anion of the other reactant (OH- from KOH) to form an insoluble product, barium hydroxide (Ba(OH)2).
The complete balanced equation is:
BaCl₂(aq) + 2KOH(aq) → Ba(OH)₂(s) + 2KCl(aq)
The net ionic equation, which shows only the species that change during the reaction, is:
Ba²⁺(aq) + 2OH⁻(aq) → Ba(OH)₂(s)
This equation is balanced both in terms of atoms and electric charge, with barium ions and hydroxide ions forming barium hydroxide, which precipitates out of the solution as a solid.
What happens as a result of the kinetic energy of the particles is a liquid being comparable with the inter molecular attractions between the particles?
1 the particles do not move enough to change positions so the liquid is not compressible
2 the particles move enough that they separate from one another and take the shape of the container
3 the particles do not move enough so they are fixed in place and the liquid has a fixed volume
4 the particles move enough that that are not fixed in place and the liquid can flow
What is an example of a molecule? (That I can draw)
Most enzymes in living things are made up of __________.
A. carbohydrates
B. lipids
C. proteins
D. nucleic acids
Answer:
The correct answer is C.
Explanation:
Enzymes are proteins that catalyze chemical reactions in living things. Enzymes are catalysts, so they are substances that without being consumed in a reaction significantly increase the speed. They do not make impossible reactions feasible but accelerate those that could spontaneously occur, increasing their speed when reacting.
Have a nice day!
why is mitosis important to all living things
a scoop of baking soda is added to a beaker containing vinager.the baking soda disapears and bubbles are observed.this is an example of an change
pls help will give crown to best answer
Which statement is true about a liquid but not a gas? It will change shape and take the shape of its container. It has more internal energy than the solid state. It allows particle to move past each other relatively easily. It has close to a constant volume as pressure is applied to it.\
Answer:
d
Explanation:
A sample of C3H8 has 7.52×1024 H atoms. How many carbon atoms does the sample contain?What is the total mass of the sample?
The C3H8 sample has 2.82 x 1024 carbon atoms and a total mass of 68.8712 g.
Explanation:Given that the number of H atoms in the C3H8 sample is 7.52 x 1024, calculating the number of propane (C3H8) molecules involves dividing that number by the amount of hydrogen atoms in a single C3H8 molecule, which is 8. This gives us the number of molecules in the sample as 9.4 x 1023 molecules.
As each propane molecule has 3 carbon atoms, the total amount of carbon atoms in the sample can be found by multiplying 9.4 x 1023 by 3, resulting in 2.82 x 1024 carbon atoms.
In order to find the total mass of the sample, we need to know the molar mass of propane, which is 44.097 g/mol. Using Avogadro's number (6.02 x 1023 molecules/mol), we can find the number of moles in the sample, which is 1.56 moles of propane. Multiplying this by the molar mass, we get that the total mass of the sample is 68.8712 g.
Learn more about Mole calculations here:https://brainly.com/question/33652783
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What is true of intercellular signals that do not go through direct connections between cells, such as plasmodesmata?
A. The signal fails to reach the inside of the cell, and the cell does not respond.
B. The signal is transferred to an adjacent cell for signal transmission.
C. An ion-linked channel to the nucleus opens up.
D. A receptor molecule accepts the signal and transports it inside the cell.
I believe that what happens here is that when those cells carrying those intercellular signals do no pass through the connections, actually the signal is passed through or are transferred to adjacent cells for signal transmission, hence the answer is:
B
I did the test and C. what correct. Could you please mark me brainiest?
minerals are classified into groups based on ____
Answer:
The correct answer is: their composition.
Explanation:
The mineral classification is based on the chemical composition and internal structure, which together represent the essence of a mineral and determine its physical properties. According to the chemical composition, minerals are divided into classes according to the dominant anion or anionic group, for example, oxides, halides, sulphides and silicates, among others.
Minerals have the same anion or dominant anionic group in their composition, so they have family similarities and characteristics more clearly and strongly marked than those that share minerals that have the same dominant cation. Examples of this are carbonates, since they resemble each other more than copper ores.
Minerals related by the domain of the same anion tend to occur together in the same place or in similar geological deposits; for example, sulphides generally occur in associations close to deposits of the type of veins or replacement, while silicates form most of the rocks in the earth's crust.