formation of a solid, formation of a gas, and a color change can also occur during some physical changes. give examples of physical changes that could produce these clues. what evidence suggests that the changes you observed in test tubes 1-3 were, in fact, chemical changes
Answer:
Examples of these physical changes are melting ice-cream, or boiling water as well as freezing it. Adding dye to water is also a physical change since the chemical compounds remain the same, it is only the physical appearance that changes.
Possible reasons for chemical changes are the formation of a precipitate (solid), or formation of gas (bubbling) as well as release of heat or light or release of odor.
A chemist adds 36.0 g of sodium chloride to 200 g of water at STP and all of the sodium chloride dissolves. What is the solute in this scenario?
A. Sodium
B. Sodium Chloride
C. Water
The solute in the scenario where a chemist adds 36.0 g of sodium chloride to 200 g of water at STP and all of the sodium chloride is sodium chloride.
What is a solute?A solute is a substance that forms a solution with another substance called solvent in a process called solubility.
According to this question, a chemist adds 36.0 g of sodium chloride to 200 g of water at STP and all of the sodium chloride dissolves in the water.
This shows that the sodium chloride is the solute added to the water (solvent).
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How many moles of oxygen are required to burn in one mole of C4H8 completely?
Answer:
6 moles of oxygen is required to burn 1 mole of C4H8 completely
Explanation:
reaction is C4H8 + (6)O2 ------ (4)CO2+ (4)H2O
When hydrogen is used in a fuel cell, the only waste product is/are __________
Answer:
water
Explanation:
The only by-products from combining hydrogen and oxygen in a fuel cell are water and heat, so hydrogen fuel cells do not emit greenhouse gases or other air pollutants as engines that use fossil fuels do.
Definition of Tissue:
Answer:
any of the distinct types of material of which animals or plants are made, consisting of specialized cells and their products
Explanation:
Does this help you?
Carbon dioxide emissions have been linked to increased air pollution. The following table lists some possible public policies aimed at reducing the amount of carbon dioxide in the air
Some possible public policies aimed at reducing the amount of carbon dioxide in the air is that companies should make use of new emissions technology to avoid air pollution.
What is air pollution?What is air pollution?Air pollution is the release of substance that are dangerous or harmful to human health into the environment.
Excessive release of carbon dioxide into the atmosphere causes pollution and deplete our ozone layer.
One of the policy government have out in check is that all companies should purchase or make use of new emissions technology to avoid polluting the environment and causing harm to human health.
Therefore, some possible public policies aimed at reducing the amount of carbon dioxide in the air is that companies should make use of new emissions technology to avoid air pollution.
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Many policies are established to control air pollution like Tradable Permit System, Corrective Tax, Command-and-Control Policy, and Corrective Subsidy.
What are air pollution control policies?A corrective subsidy is a policy that encourages people to plant trees. Command-and-Control Policy or the regulation policy limits the emission of the particles that affect and harms the air and mandates the use of emissions-reducing technology.
Corrective Tax policy discourages negative effect behavior and imposes Pigovian tax that helps in achieving optimal pollutants. Tradable Permit System allows the figuring of the individual pollution emission.
Therefore, public policies are aimed to reduce air pollution through various means.
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what is the molarity of a solution in which 65.3 NaNO3, are disssolved in enough water to make 1250 mL of solution?
Answer:
1242
Explanation:
is respiration like burning?Explain your answer.
Answer:
Yes
Explanation:
The process of respiration and burning are similar in the following ways: Both respiration and burning require oxygen. Energy is released during both respiration and burning. The products produced (carbon dioxide and water) are the same for both respiration and burning.
Answer:
Yes
Both Respiration and Burning uses oxygen. Both Respiration and Burning produces energy. Both Respiration and Burning gives out carbon dioxide as the end product. The overall chemical reactions of both Respiration and Burning are the same.
Explanation:
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Write a full note on Infectious diseases. please I need it now and no links please thanks
Answer:
diseases where microbes are the immediate cause are called infectious diseases. Infectious diseases are disorders caused by organisms — such as bacteria, viruses, fungi or parasites. Many organisms live in and on our bodies. They're normally harmless or even helpful.
1. Which would dissolve faster?
A. individual salt crystals
B. a big block of salt
2. most cases , when temperature increases , solubility
A. increases
B. decreases
3. As agitation increases , the rate at which a solute will dissolve
A. increases
B. decreases
1) A. individual salt crystals
2) A. increases
3) A. increases
hope this helps :)
A solution is defined as the homogeneous mixture which contain one or more solutes in a solvent. The factors which affect the solubility are temperature and pressure. Here individual salt crystals dissolve faster.
What is solubility?The maximum amount of solute which can dissolve in a given quantity of the solvent at a certain temperature is defined as the solubility. It is defined as the property exhibited by a material to dissolve in a given solvent.
The powdered salt found to dissolves faster in a solvent than the salt of larger size. The rate of dissolving is affected by the size of the solute. The faster the solute dissolves if its size is smaller. So the individual salt crystals dissolves faster.
In most cases, generally the solubility found to decrease with the increase of temperature. When the temperature increases, the kinetic energy of the molecules increases and thereby decreases the intermolecular force of attraction. The increase in the process of agitation decreases the solubility.
1. The correct option is A
2. The correct option is B
3. The correct option is B
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b
Identify a compound composed of
molecules
Answer:
nitrogen oxides and hydrogen
1. Describe the liquid state according to the
kinetic-molecular theory.
Answer:
Liquids have more kinetic energy than solids. When a substance increases in temperature, heat is being added, and its particles are gaining kinetic energy. Because of their close proximity to one another, liquid and solid particles experience intermolecular forces. These forces keep particles close together.
Explanation:
hope it helps U
N2(g)+3H2(g) 2NH3(g)
The equilibrium system described by this equation has
reactant molecule(s)
and
product gas molecule(s).
Considering the definition of chemical equation, the equilibrium system described by this equation has 4 reactant molecules and 2 product gas molecules.
Definition of chemical equationA chemical equation is a symbolic description used to describe the identities and relative quantities of the reactants and products involved in a chemical reaction.
The information contained in the chemical equation allows us to determine the substances that are transformed or modified in a reaction, called reactants or reagents, and the new substances that originate in a chemical reaction, called products.
The chemical equation must comply with the Law of conservation of matter. That is, the equation must indicate that the number of atoms of the reactants and products is equal on both sides of the reaction and that the charges are also equal.
Number of reactant molecule(s) and product gas molecule(s)In this case you know:
N₂ + 3 H₂ ⇄ 2 NH₃
You can observe that the number of H₂ is 3, while the number of N₂ is 1.
The number of molecules on the reactant side is the sum of hydrogen and nitrogen molecules. Then, the total number of reactant molecule is 4.
The number of product molecules are only the number of NH₃. Then, the number of product molecules are 2.
Finally, the equilibrium system described by this equation has 4 reactant molecules and 2 product gas molecules.
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Answer:
4 and then 2
Explanation:
According to the kinetic theory of gases, an ideal gas molecule
Answer:
According to the kinetic theory of gases, in an ideal gas between two successive collisions, a gas molecule travels in a straight line.
12. You want to create a 0. 55M Potassium Chloride solution. You mass 3. 00 grams of Potassium chloride
How much water is needed?
I suppose that you want to produce a 0.25 M solution of KCl
You do not want tp produce 0.25 mol of KCl.
Molar mass KCl = 39.1 + 35.45 = 74.55 g/mol
Mass of 0.25 mol KCl = 0.25 mol * 74.55 g/mol =18.64 g
To produce a 0.25 M solution of KCl = 18.64 g would require a solution volume of 1.0 L or 1000 mL
You have only 5.00 g ( NOT 5.00 gm) of KCl
Volume of solution required = 5 g / 18.64 g * 1000 mL = 268 mL solution
You dissolve the 5 g KCl in some water and then make up the final solution volume to 268 mL
This does NOT mean that you dissolve the 5 g KCl in 268 mL water .
A reaction that is spontaneous at low temperature can become non spontaneous at high temperature if δh is\
Answer:
Reaction
Explanation:
A reaction that is spontaneous at low temperature
It's sunny in new york, but it is cool. where would you expect to find this lizard during the day? question 16 options: under a rock in a damp stream bed basking in a sunny spot in a hole in the ground
It's sunny in new york, but it is cool, we will expect to find lizard under a rock or in a hole in the ground.
Why lizards are not comfortable in cold?Lizards are not comfortable in the cold season as they are cold blooded animal, so their body will gets slow in the winter season.
During the winter season or in the cool weather, lizards will go to the places where they faces less cooling. And these places be like inside the rocks, under a hole, under the ground, in the trunks of trees, etc.
Hence, options (1) and (4) are correct.
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This part insulates the reaction chamber from the transfer of heat to or from the surrounding environment. this part contains a known amount of water, which is placed there before the experiment starts. this part is where the metal is placed at the beginning of the experiment. this part is used for measuring the initial and final temperatures of the water.
The amount of heat transferred in and out of the system is measured by calorimetry. The thermometer in the calorimeter is used to measure the temperature.
What are the parts of the calorimetry device?The thermometer (A) is a device used to measure the final and the initial temperature of the water or any other liquid in a system. A metal vessel is a place where the reaction mixture is present.
In-vessel (B), water, and metal are placed before the beginning of the experiment. The styrofoam cup or the outer metal vessel (C) insulates the instrument, from regulating the heat transformation.
Therefore, part A measures the temperature of the reaction mixture.
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Would the ph at the equivalence point be acidic, basic, or neutral for each given titration?.
The pH at equivalence point depends on the nature of the acid-base titration, and can either be acidic, basic, or neutral.
What is equivalence point?The equivalence point in a titration is the point at which equal amount of acid and base have reacted with each other.
The pH at equivalence point depends on the nature of the acids and bases being titrated.
pH at equivalence point will be:
neutral in a strong acid and strong base titrationacidic in a strong acid and weak base titration basic in a weak acid and strong base titrationTherefore, the pH at equivalence point depends on the nature of the acid-base titration.
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Compare and contrastthe properties of the individual elements that combine to make salt with the compound salt
Answer:
I believe is the correct answer
Explanation:
NaCl made,2(NaCl)or2NaCl,Na2Cl,NaCl2 all represent compounds
Given the following equation: Cu + 2 AgNO3 ---> Cu(NO3)2 + 2
Ag How many grams of Cu are needed to react with 262g moles of
AgNO3?
Given the following equation; Cu + 2AgNO3 = Cu(NO3)2 + 2Ag, 48.97 grams of Cu are needed to react with 262g of AgNO3.
How to calculate mass of substances?The mass of a substance can be calculated using the following steps:
Cu + 2AgNO3 = Cu(NO3)2 + 2Ag
1 mole of Cu react with 2 moles of AgNO3
Molar mass of AgNO3 = 169.87 g/molMolar mass of Cu = 63.5g/molmoles of AgNO3 = 262g/169.87g/mol = 1.54mol
1.54 moles of AgNO3 will react with 0.77 moles of Cu.
mass of Cu = 0.77 × 63.5 = 48.97g
Therefore, given the following equation; Cu + 2AgNO3 = Cu(NO3)2 + 2Ag, 48.97 grams of Cu are needed to react with 262g of AgNO3.
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Marble(calcium carbonate) reacts with hydrochloric acid(hcl) to form calcium chloride solution, water, and carbon dioxide. Find the percent yield of carbon dioxide if 3. 65 grams
Answer:
When calcium carbonate reacts with hydrogen chloride, it reacts to form calcium chloride, carbon dioxide, and water. If this reaction occurs with 51.6% yield, what mass of carbon dioxide will be collected if 16.93 g of CaCO3 is added to sufficient hydrogen chloride
Help me describe air pollution and its causes.
Here is a Answer to your question:
Air pollution is caused by solid and liquid particles and certain gases that are suspended in the air. These particles and gases can come from car and truck exhaust, factories, dust, pollen, mold spores, volcanoes and wildfires. The solid and liquid particles suspended in our air are called aerosols.
Here are the 8 causes of air pollution?
1: The Burning of Fossil Fuels
2: Industrial Emission
3: Indoor Air Pollution
4: Wildfires
5: Microbial Decaying Process
6: Transportation
7: Open Burning of Garbage Waste
8: Construction and Demolition
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What happens to a catalyst as the result of a chemical reaction?
A.) It slows a chemical reaction.
B.) It is not consumed.
C.) It is consumed.
D.) It changes to something else.
The catalyst is recovered unchanged in amount and chemical composition at the end of a reaction. It speeds up only a spontaneous reaction, not a spontaneous one. It is not consumed in a reaction. The correct option is B.
What is a catalyst?A substance which increases the rate of a reaction without itself undergoing any permanent change chemically or quantitatively is defined as the catalyst and the phenomenon is known as the catalysis. It is believed that a catalyst actually participates in the chemical reaction that it speeds up.
A catalyst does not affect the position of equilibrium of a reversible reaction and thus do not alter its equilibrium constant. This is because it speeds up the forward and backward reactions to the same extent. It shows some specificity in its action.
It does not alter the Gibbs energy.
Thus the correct option is B.
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In a terrarium, the pincushion moss, the echeveria, and the moon cactus make up which of the following? Select all that apply. A. a population B. part of a community C. part of an ecosystem
The pincushion moss, the echeveria, and the moon cactus in a terrarium make up a community.
What is a community of organisms?A community of organisms refers to a group of organisms of different species which are found living together in the same habitat.
Populations of organisms of different species within the same habitat constitute a community.
The pincushion moss, the echeveria, and the moon cactus are all different species found within the same habitat, a terrarium.
Therefore, the different species of organisms in the terrarium make up a community.
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Answer: part of a community and part of an ecosystem
Explanation:
Two substances are combined and react. After 10 minutes, the chemical reaction has reached equilibrium. Which values would be equal to zero for the solution?
The extra conversion of concentration of reactant and product should be zero in order to attaining equlibrium state.
What is equilibrium?Chemical equilibrium refers to the state in which both the reactants and products are present in equal concentrations or amount. In equlibrium, same amount of reactant is converted into product and product into reactant.
So we can conclude that the extra conversion of concentration of reactant and product should be zero in order to attaining equlibrium state.
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_______ oxides are oxides of certain non metals
acidic in naturenature
Generally, Oxides of non-metals are acidic in nature. When non-metals are reacted with water it forms an acidic solution. The common oxides of Sulphur, Selenium, and Bromine are strongly acidic.
Does electronegativity affect replacement reactions
Elecetronegativity will affect the replacement reactions as it attracts the bonded electrons towards itself.
What is replacement reaction?Replacement reactions are those reactions in which replacement of any one element from any compound is done by any other element.
Electronegativity is the attracting power of any element to hold the bonded electron towards itself so that they will bear a partial negative charge on itself. If in any reaction replacement of anion is required and any compound have more electronegative element which bounded the bonded electron strictly and will not allow the formation of anion then it affects the activity of the reaction.
Hence electronegativity affect the replacement reactions.
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Daffodils and tulips are examples of which of these?
a.cuttings
b.bulbs
c.runners
d.tubers
Answer: bulbs
Explanation: Daffodils and tulips are examples of bulbs.
Answer: Bulbs
Explanation: When you plant daffodils or tulips, you will see that the "seeds" are onion-like. Onions are bulbs, and so are daffodils and tulips.
Which describes the enthalpy change associated with an endothermic reaction? *
2 points
ΔH is negative
ΔH is zero
ΔH is positive
Answer:
It is negative because the enthalpy of the products is greater than the enthalpy of the reactants.