the answer is guyots
You see a burning candle. You feel heat above the flame, you see black smoke rising from the wick, and wax melts. List each of the changes that occurred and tell the type of change that caused it.
A burning candle undergoes several changes: heat production, smoke emission, and wax melting. The forming of water vapor and carbon dioxide during heat production and the generation of soot particles during smoke emission are chemical changes. The melting of the wax is a physical change.
Explanation:Three changes occur when you see a burning candle: the production of heat, the emission of smoke, and the melting of wax.
Production of Heat: When you light a candle, the heat of the flame melts the wax near the wick. This liquid wax is drawn up the wick towards the flame. The heat of the flame vaporizes the liquid wax (turns it into a hot gas) and starts to break down the hydrocarbons into molecules of hydrogen and carbon. These vaporized molecules are drawn up into the flame, where they react with oxygen from the air to create heat, water vapor, and carbon dioxide. This process is an example of a chemical change because new substances (water vapor, carbon dioxide) are formed. Emission of Smoke: This is also a chemical change resulting from incomplete combustion. When the flame doesn't get enough oxygen, it can't totally break the hydrocarbons, resulting in small soot particles that scatter light (black residue). Melting of Wax: The wax near the wick melts due to the heat of the flame. This is a physical change since it involves a change of state (solid wax to liquid), but the chemical composition of the wax stays the same. Learn more about Candle Burning here:
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Which one is a true statement about exothermic reactions?
A. Energy from an outside source is continuously being added.
B. The reaction container always feels cold.
C. The reactants have more heat energy than the products.
D. More heat is given off than is put into the reaction.
Which of these is an example of physical change?
Melting a Substance
Breaking chemical bonds
Forming chemical bonds
Nuclear decay
Melting a substance is an example of physical change. Thus option A is correct.
What is physical change?Change is defined as the act, procedure, or outcome of changing: for instance. Change refers to a shift in the weather, transformation refers to a period of profound social change, and substitution refers to a change in the environment.
Change can also be defined as a procedure whereby one or more compounds are chemically transformed into others.
There are two types of changes.
Chemical change - It is defined as a transformation of one material into another, the formation of new materials with distinct properties, and the creation of one or more new substances.Physical change - It is defined as a sort of transformation in which the composition of matter changes but no new material is created. Cutting, bending, dissolving, freezing, boiling, and melting are some of the example of physical change.Thus. melting a substance is an example of physical change. Thus option A is correct.
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Which of these substances are molecules
What is the pressure of nitrogen in atmospheres of a sample that is at 745 mmHg?
Copper is more reactive than calcium. True or false?
Answer;
The above statement is false
Explanation;
Copper is less reactive than Calcium.
This is because Calcium is higher in the reactivity series of metals compared to copper and thus reacts more than copper.
The reactivity series of metals is vital tool that is used in determining the products of displacement reactions and the reactivity of metals in other reactions. The higher the metal is in the reactivity series, the more reactive it is and conversely the lower the metal in the reactivity series the less reactive it is.
In this case, calcium is higher in the reactivity series than copper thus more reactive.
Answer: The given statement is false.
Explanation:
Electronic configuration of calcium is [tex]1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}[/tex], that is, there are two extra electrons. So, in order to attain stability calcium loses two electrons readily.
Whereas electronic configuration of copper is [tex][Ar]4s^{1}3d^{10}[/tex]. Since, it has completely filled d-orbital so, it is stable in nature and thus, does not react readily.
Therefore, we can conclude that reactivity of calcium is more than copper. That is why, the given statement is false.
Which two forms of heat transfer work together to heat water in a plastic bottle
The two forms of heat transfer that work together to heat water in a plastic bottle are conduction and convection.
Heat transferHeat is transferred through solid materials by a process known as conduction.
In liquids, heat is transferred by convectional currents.
For water in a plastic bottle, heat will first have to travel through the solid plastic bottle by conduction before heating the water inside the bottle by convection.
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Which two structures would provide a positive identification of a plant cell under a microscope? A. cytoskeleton, cell wall B. endoplasmic reticulum, chloroplasts C. chloroplast, large central vacuole D. large central vacuole, flagellum
A 20.0 % by mass solution of phosphoric acid (H3PO4) in water has a density of 1.114 g/mL at 20°C. What is the molarity of this solution?
Answer:
Molarity is 2.272M
Explanation:
The mass % of phosphoric acid is 20.0%
It means in 100 g of solution there is 20g of phosphoric acid in it.
Molarity = moles of solute dissolved per litre of solution.
So we need volume of solution
Volume can be calculated from mass and density as
Volume = mass / Density = 100/1.114 = 89.77 mL = 0.08977 L
Moles of solute = mass of solute / molar mass of solute
moles of solute = 20g / 98 = 0.204
molarity = [tex]\frac{moles}{volume}=\frac{0.204}{0.08977} =2.272M[/tex]
Yttrium -90 has a half life of 64 hours . How much of a 120g sample will remain after 128 hours ?
what is the mass of 4.00 cm3 piece of sodium chloride having a density of 2.16 g/cm3 chemistry
Answer : The mass of sodium chloride is, 8.64 grams
Explanation : Given,
Volume of sodium chloride = [tex]4cm^3[/tex]
Density of sodium chloride = [tex]2.16g/cm^3[/tex]
Formula used :
[tex]\text{Density of }NaCl=\frac{\text{Mass of }NaCl}{\text{Volume of }NaCl}[/tex]
Now put all the given values in this formula, we get mass of sodium chloride.
[tex]2.16g/cm^3=\frac{\text{Mass of }NaCl}{4cm^3}[/tex]
[tex]\text{Mass of }NaCl=8.64g[/tex]
Therefore, the mass of sodium chloride is, 8.64 grams
what is the percent composition of the u.s quarter, which has the mass of 5.670g
and contains 5.198g Cu and 0.472g Ni
Final answer:
The percent composition of Cu in the US quarter is approximately 91.72%.
Explanation:
The percent composition of an element in a compound is the percentage of the total mass of the compound that is due to that element.
To calculate the percent composition of Cu in the US quarter, we need to divide the mass of Cu by the total mass of the quarter and multiply by 100.
Percent composition of Cu = (Mass of Cu / Mass of quarter) x 100
Mass of quarter = Mass of Cu + Mass of Ni = 5.198g + 0.472g = 5.670g
Percent composition of Cu = (5.198g / 5.670g) x 100 = 91.72%
Final answer:
The U.S. quarter, with a mass of 5.670g, is composed of approximately 91.67% copper and 8.32% nickel, calculated using the mass of the individual elements and the total mass of the coin.
Explanation:
To find the percent composition of the U.S. quarter with a mass of 5.670g, which contains 5.198g of copper (Cu) and 0.472g of nickel (Ni), you can use the formula:
Percent Composition = (mass of element/mass of compound) × 100%.For copper (Cu): Percent Composition of Cu = (5.198g / 5.670g) × 100% = 91.67%.For nickel (Ni):
Percent Composition of Ni = (0.472g / 5.670g) × 100% = 8.32%.Therefore, the U.S. quarter is composed of approximately 91.67% copper and 8.32% nickel.
how did ernest rutherford change the atomic model?
He showed that most of an atom's mass was located in the atom's nucleus.
Ernest Rutherford changed the atomic model by postulating that most of the mass of an atom is present in it's nucleus.
What is an atom?An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.
The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.
Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.
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The standard unit of mass is the: gram kilogram pound cubic centimeter
Answer:
The standard unit of mass is the kilogram.
Explanation:
The kilogram is the basic unit of mass in the International System of Units. Among the seven basic units of the International System of Units, kilograms are the only basic unit with a prefix.
The XXVI General Conference on Weights and Measures of 2018 approved the definition of a kilogram based on fixing the numerical value of the Planck constant. The decision entered into force on May 20, 2019.
How many grams of Hydrogen (H) would need to react with 190 grams of Fluorine (F) to make 200 grams of HF (Hydrofluoric Acid)? Question 6 options: 200 20 10 5
10 g of H₂
Solution:The Balance chemical equation is as follow,
F₂ + H₂ → 2 HF
Step 1: Calculate Amount of F₂ required to form 200 g of HF:
According to balance equation,
40 g (2 mol) HF is formed by = 38 g (1 mol) of F₂
So,
200 g of HF will be formed by = X g of F₂
Solving for X,
X = (200 g × 38 g) ÷ 40 g
X = 190 g of F₂
Step 2: Calculate amount of H₂ to react with 190 g of F₂:
According to equation,
38 g (1 mol) F₂ required = 2 g (1 mol) of H₂
So,
190 g of F₂ will require = X g of H₂
Solving for X,
X = (190 g × 2 g) ÷ 38 g
X = 10 g of H₂
Critical Thinking:
Suppose you need to build a raft. Write a paragraph describing the physical and chemical properties of the raft that would be important to ensure your safety.
To ensure safety when building a raft, one must evaluate physical properties such as buoyancy, water-resistance, stability, and balance, as well as chemical properties that dictate material inertness and resistance to degradation.
In building a raft to ensure safety, one must consider both physical and chemical properties. It is crucial that the materials selected are buoyant to keep the raft afloat. The materials should also be water-resistant to minimize water absorption, which could lead to deterioration or increased weight causing the raft to sink. Stability and balance are also critical physical properties, as they help prevent the raft from flipping over in water.
From a chemical standpoint, the materials should be inert and non-reactive with water or the substances in it to prevent the raft from breaking down over time. Chemical treatments may be applied to enhance water resistance or prevent biological growth such as algae or bacteria on the raft which can weaken materials or make the surface slippery. Selection based on quality and construction is more practical for safety than aesthetics like color or superficial measures such as size.
Furthermore, when considering the construction method, one must ensure that all parts of the raft are securely bound to avoid disintegration under stress. A sensible selection process is paramount, involving critical evaluation of each raft's potential problems and considering how these could impact safety and performance during river crossing.
Which example provides a complete scientific description of an object in motion? Question 3 options: The marble changed position quickly. The car traveled north. The marble moved 30 cm north in 6 seconds. The ball rolled 20 cm in 5 seconds.
Answer:
The marble moved 30 cm north in 6 seconds. is correct
Explanation:
according to K12
100% sure
Define prediction and explain how it is used to formulate a hypothesis.
Answer:a prediction is a scientific guess that’s solely based on known knowledge
Explanation:
A prediction is used to make a hypothesis because it goes in hand of guessing an outcome that can be tested
A prediction is a scientific guess that is based on knowledge which is known.
What is knowledge?Scientific knowledge is defined as a systemic explanation of phenomenon or behavior of interest that are obtained using the scientific method. The principal on which scientific knowledge depends is the test of knowledge.
The fact which makes scientific knowledge different from other knowledge is that it depends upon fact and scientific resources as well as data. Scientific knowledge helps us to improve and develop new technology find solution of practical problems and make informed decisions.
The procedure of aquaring scientific knowledge is a result of practice of the several method such as observation, filtering hypothesis, deduction of test for hypothesis following testing and experimentation which lead to confirmation or failure of the hypothesis.
Therefore, A prediction is a scientific guess that is based on knowledge which is known.
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dust mites are microscopic bugs that are too small to see with the dissecting microscope. to see the details of a dust mite's skin, which of the following microscopes would you use? Please help fast with make brainiest
A.dissecting microscope
B.compound microscope
C.transmission electron microscope
D.scanning electron microscope
I know the answer is not A.
Nevermind got the answer it is D.
The scanning electron microscope is used to see the details of a dust mite's skin. Thus option D is correct.
What is microscope?Microscope is defined as an optical equipment that magnifies an object by using a lens or a combination of lenses.
It can also be defined as an optical equipment consisting of a lens or group of lenses used to magnify images of small things.
There are five types of microscopes.
Simple microscopeCompound microscopeElectron microscopeStereomicroscopeScanning electron microscopeThus, the scanning electron microscope is used to see the details of a dust mite's skin. Thus option D is correct.
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Vegetable oil has the density of .92 g/mL and honey has the density of 1.42 g/mL. Which liquid will float?
write the symbols for the ions that form when potassium and iodine react to form the ionic compound potassium iodide?
The symbols for the ions that form when potassium and iodine react to create potassium iodide are K+ for potassium and I- for iodine. These ions combine to form the compound with the chemical formula KI.
Explanation:When potassium and iodine react to form the ionic compound potassium iodide, the symbols for the ions involved are K+ for the potassium ion and I- for the iodine ion. Potassium, being in group 1 of the periodic table, loses one electron to form the K+ ion, while iodine, in group 17, gains one electron to form the I- ion. This transfer of electrons results in the formation of an ionic bond between the two ions.
Potassium iodide is represented by the chemical formula KI, indicating that there is a one-to-one ratio of potassium ions to iodine ions in the compound.
Final answer:
The symbols for the ions are K+ for potassium and I- for iodine, which together form the ionic compound potassium iodide (KI).
Explanation:
The symbols for the ions that form when potassium and iodine react to form the ionic compound potassium iodide are K+ and I−. Potassium, which is in group 1 of the periodic table, loses one electron to form a K+ ion. Iodine, on the other hand, is in group 17 of the periodic table and gains one electron to form an I− ion. When these two ions combine, they form the ionic compound potassium iodide (KI).
HELP!!!!! a car traveling at a constant 50 miles per hour turns left on the interstate. what is happening here? A) nothing because the speed is constant B) velocity because the direction is changing C) acceleration because speed is constant but, direction is changing D) displacement because the car is moving
Answer is: B) velocity because the direction is changing.
Velocity is equivalent to a specification of its speed and direction of motion, for example 100 km/h to the east.
Velocity is a physical vector quantity (measured in metres per second) and need magnitude and direction to define it, for example 100 metres per second east.
How do you know if a reaction is endothermic?
very reactive nonmetal element has most protons in the halogen group
if a hill or Mountain has a high gradient (slope) what happens to the speed of a river flowing downward and the rate of erosion?
Match the scientist with his discovery or contribution.
Match
Term
Definition
J. J. Thomson A) Protons
John Dalton B) Atoms
Ernest Rutherford C) Electrons
James Chadwick D) Neutrons
I NEED THIS IN 5 MINUTS MAX
Thomson - Electrons
Dalton - Atoms
Rutherford - Protons
Chadwick - Neutrons
will be the answer
The correct match of the scientists with their discovery are:
A. J. J. Thomson - Electrons
B. John Dalton - Atoms
C. Ernst Rutherford - Protons
D. James Chadwick - Neutrons
What are subatomic particles?An atom is made up of subatomic particles. Electron, proton, and neutron are the particles that form an atom.
Electron was discovered in 1898 and proton was discovered in 1908 and neutron was discovered in 1932.
Thus, the correct options are, A. J. J. Thomson - Electrons
B. John Dalton - Atoms
C. Ernst Rutherford - Protons
D. James Chadwick - Neutrons
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What is the chemical name and formula of a compound that has one carbon atom and four chlorine atoms?
carbon tetrachloride; CCl4
chlorine carbide; Cl4C
carbon chloride; Cl4C
monocarbon tetrachloride; CCl4
The correct chemical name and formula for a compound that has one carbon atom and four chlorine atoms is carbon tetrachloride, represented by the formula CCl4. Therefore option 1 is correct.
"carbon tetrachloride; CCl4," is the correct answer. Carbon tetrachloride is a compound composed of one carbon atom (C) bonded to four chlorine atoms (Cl).
The prefix "tetra-" indicates that there are four chlorine atoms, and "chloride" refers to the chlorine ion. Therefore, the name "carbon tetrachloride" accurately describes the compound's composition.
Thus, the correct chemical name and formula for a compound with one carbon atom and four chlorine atoms is carbon tetrachloride (CCl4).
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In this chemical reaction a very reactive metal, sodium, combines with a poisonous gas and results in the formation of ordinary table salt. In the chemical reaction ______________ is the product.A)NaB)NaClC)Cl2EliminateD)a reactive metalDescribe the mass of the reactants and products given the balanced chemical reaction. A) The mass of the products is 2 3 that of the reactants. B) The mass of the reactants equals the mass of the products. C) The mass of the reactants is less than the mass of the products. Eliminate D) The mass of the reactants is greater than the mass of the products.
Antoine Lavoisier found that mass was conserved in chemical reactions when he saw thatA)heat was released in chemical reactions.B)the products differed greatly from the reactants.C)the mass of the products was the same as that of the reactants.EliminateD)the mass of the products were heavier than the mass of the reactants.
A copper sheet is heated in a furnace until it melts. The hot liquid copper is then cooled until it becomes solid again. Compare the mass of the copper before and after melting.A)The new solid copper is lighter than the original sheet.B)The new solid copper is heavier than the original sheet.C)The new solid copper is the same weight as the original sheet.EliminateD)The molten copper was lighter than the sheet or the new solid.
The equation below shows the products formed when a solution of silver nitrate (AgNO3) reacts with a solution of sodium chloride (NaCl).
AgNO3 + NaCl → NaNO3 + AgCl
(Reactants) → (Products)
In this equation, the total mass of the reactants is
A) equal to the mass of AgCl.
B) less than the mass of AgCl.
C) equal to the total mass of the products.
D) greater than the total mass of the products.
In the given equation, the total mass of the reactants is equal to the total mass of the products. Therefore, option (C) is correct.
What is the balanced chemical equation?A chemical equation can be defined as the representation of a chemical reaction in terms of symbols of the substances. A balanced equation consists of reactants, formed products, and an arrow representing the direction of the chemical reaction.
The chemical equation in which the number of atoms of each element participated in the reaction is equal on either side of the equation is called a balanced chemical equation.
The law of conservation of mass must obey by a balancing of a chemical equation. According to this law, in a chemical reaction, the mass can neither be created nor destroyed.
The total mass on the reactant side should be equal to the total mass on the product side in a balanced chemical equation.
For the given chemical equation total mass of AgNO₃ and NaCl is equal to the total mass of NaNO and AgCl.
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The table below shows the average temperatures of the crust, the mantle, and the outer and inner core of Earth arranged randomly:
Average Temperature of Layers Unknown Layer
Average Temperature (°C) A 4,500 B 1,300 to 2,500 C 5,000 D 0 to 1,300 Which layer is most likely the mantle?
someone please help 10 points science
B is most likely to be the mantle 1,300-2,500 YOUR WELCOME
Average temperature of layers unknown layer average temperature is 1,300 to 2,500. The crust's temperature is between 200° Celsius and 400° Celsius close to the Moho.
What is average temperature ?The average air temperature throughout a specific time period, often a day, a month, or a year, as measured by a thermometer that has been properly exposed. The mean temperature is often calculated for the year and for each month in climatological tables.
Normal and average temperatures have different connotations according to meteorologists than they do in regular language. A normal temperature is higher than the mathematical average of an average temperature.
The combined temperatures of all the hot regions, all the cold places, and all the in-between locations make up the global average temperature. It is a crucial indicator of how the Earth's system is changing.
Thus, option B is correct.
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