Which chemicals previously used in products such as refrigerants, aerosol sprays, and cleaning products contributed to the depletion of the ozone layer
Answer:chlorofluorocarbons (CFCs) could deplete Earth's atmospheric ozone layer, which blocks the sun's damaging ultraviolet rays. When the scientists reported their findings in 1974, CFCs were widely used as refrigerant gases and as propellants in aerosol sprays
Explanation:
Fluorine-18 undergoes positron emission as shown:
18 F + 4x +48
Enter the appropriate values for A and Z and the chemical
symbol for X
A:
Z:
83
1
X:
Answer:Answer:
40-18 fl =>40-cl+cl+0-1e sorry if im rong
Explanation:
When [tex]^1^8F[/tex] undergoes positron emission, the product nucleus is, [tex]^1^8O[/tex].
What is a positron emission?In positron emission, also called positive beta decay (β+ decay), a proton in the parent nucleus decays into a neutron that remains in the daughter nucleus, and the nucleus emits a neutrino and a positron, which is a positive particle like an ordinary electron in mass but of opposite charge.
When a proton is converted into a neutron then the positron emission takes place as follows.
[tex]^1_1p\;\rightarrow\;^1_0n\;+\;^0_+1e[/tex]
A positron is represented by the symbol. Therefore, when a positron emission occurs then the resultant nuclei atomic number decreases by a unit mass.
The general equation representing positron emission is as follows.
[tex]^M_ZA\;\rightarrow\;^M_Z_-_1 B\;+\;^0_+1e[/tex]
Hence, fluorine-18 decays by positron emission as follows.
[tex]^1^8_9F\;\rightarrow\;^1^8_8n\;+\;^0_+1e[/tex]
Therefore, when [tex]^1^8F[/tex] undergoes positron emission, the product nucleus is, [tex]^1^8O[/tex].
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what type of weather does a warm front cause and why
why must a ph meter be calibrated by using a solution with a known ph value
Answer:
A pH calibration is the process of adjusting your pH meter by measuring solutions of a known pH value. This is because the characteristics of your electrode will change over time and this needs to be compensated for. A calibration does this by matching your pH meter to the current characteristics of your pH sensor.
Explanation:
How many moles of AgNO3 must react to form 0. 854 mol Ag? mol AgNO3.
The moles of silver nitrate required to form 0.854 mol silver ion has been 0.854 mol.
The balanced chemical equation for the dissolution of silver nitrate has been:
[tex]\rm AgNO_3\;\rightarrow\;Ag^+\;+\;NO_3^-[/tex]
The aqueous solution of silver nitrate has been dissociated into the constituent silver and nitrate ions.
In a balanced chemical equation, the coefficient has been equivalent to the moles of each reactant forming the moles of product.
From, the balanced equation,
[tex]\rm 1\;mol\;AgNO_3=1\;mol\;Ag[/tex]
The given moles of Silver has been 0.854 mol. Thus, the moles of silver nitrate required has been given as:
[tex]\rm 1\;mol\;Ag^+=1\;mol\;AgNO_3\\0.854\;mol\;Ag^+=0.854\;\times\;1\;mol\;AgNO_3\\0.854\;mol\;Ag^+=0.854\;mol\;AgNO_3[/tex]
The moles of silver nitrate required to form 0.854 mol silver ion has been 0.854 mol.
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Why can't percent yield be greater than one hundred percent?
Answer:
Percent yield is the maximum amount of product that can be formed in a reaction. Matter cannot be created or destroyed according to the law of conservation of mass, so you cant have over 100%.
Explanation:
Please help to complete this
Mr. Jenson's class is observing the growth of one kind of pea plant.
The class wants to design an experiment to answer the question, "What amount of water will cause the plants to produce the greatest number of peas?"
What could the class do to create the experiment?
A.
give all the pea plants the same amount of water and count the number of peas that the plants produce
B.
give all the pea plants different amounts of water and only guess the number of peas that the plants produce
C.
give all of the pea plants different amounts of water and count the number of peas that the plants produce
D.
stop watering all of the pea plants and then count the number of peas that the plants produce
Answer:
The answer would be C. Giving the pea plants a different amount of water in each one can help you observe how much water produces the most peas in a pea pod.
The answer is C to give all of the pea plants different amounts of water and count the number of peas that the plants produce
Explanation:
Answer:
C. give all of the pea plants different amounts of water and count the number of peas that the plants produce
Explanation:
The class wants to design an experiment that answers the question, "What amount of water will cause the plants to produce the greatest number of peas?"
To answer the question, the experiment should show how many peas the plants produce when they are given different amounts of water. The best way to do this would be to give all of the plants different amounts of water and count the number of peas that the plants produce.
PLEASE HELP CHEMISTRY
What is the hydronium ion concentration of a solution with a POH of 6.90?
O 6.29 x 10-7 M
6.53 x 10-7 M.
O 7.18 x 10-8 M
O 7.94 x 10-8 M
Answer:
O 7.94 x 10-8 M
Explanation:
Did the test
The hydronium ion concentration of a solution with a pOH of 6.90 is 7.94 × 10⁻⁸ M.
What is the relation between pH & pOH?Relation between the pH and pOH will be represented by the below equation as:
pH + pOH = 14
Given that pOH = 6.90
So, pH = 14 - 6.90 = 7.1
Also we know that, pH = -log[H⁺]
[H⁺] = [tex]10^{-pH}[/tex]
[H⁺] = [tex]10^{-7.1}[/tex]M
[H⁺] = 7.94 × 10⁻⁸ M
Hence the concentration of hydronium ion is [tex]10^{-7.1}[/tex] M.
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What is formed if two or more atoms join together?
A. Compound
B. Electronegativity
C. Nucleus
D. Element
HELP
Answer:
compound
Explanation:
compound = A substance consisting of atoms or ions of two or more different elements in definite proportions joined by chemical bonds into a molecule.
A tank of syngas produced by coal gasification contains 60.0% carbon monoxide, 30.0% hydrogen, and 10.0% carbon dioxide. What is the mass of hydrogen (in g) in 1.00 cubic meter of this syngas mixture at 1.00 atm and 25.0 °C? (1 m³ = 1000 L)
Considering the ideal gas law, the mass of hydrogen is 24.552 grams.
An ideal gas is a theoretical gas that is considered to be composed of randomly moving point particles that do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.
An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of the gases:
P× V = n× R× T
In this case, you know:
P= 1 atmV= 1 m³= 1000 Ln= ?R= 0.082[tex]\frac{atmL}{molK}[/tex]T= 25 °C= 298 °KReplacing in the ideal gas law:
1 atm× 1000 L = n× 0.082[tex]\frac{atmL}{molK}[/tex]× 298 K
Solving:
[tex]n=\frac{1 atmx1000 L}{0.082 \frac{atmL}{molK}x298 K}[/tex]
n= 40.92 mol
The mol of syngas mixture is 40.92 mol.
Syngas mixture contains 30.0% hydrogen. So, there is a mol fraction of [tex]x_{hydrogen} =[/tex]0.3 . Thus, the mols of hydrogen in syngas mixture is calculated as:
40.92 moles of syngas mixture× 0.3= 12.276 moles of hydrogen
Finally, being the molar mass of hydrogen H₂ 2 [tex]\frac{g}{mole}[/tex], then the mass is:
[tex]12.276 molesx\frac{2 grams}{1 mole}[/tex]= 24.552 grams
In summary, the mass of hydrogen is 24.552 grams.
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Which model provides more information-a chemical formula or a sketch of the molecule
like in the structural formula? Explain your reasoning.
Answer:
Explanation
:Both b/c a chemical formula tells you how many and a sketch formula shows how they are bonded together.
Molecular formulas show how many atoms of each element one molecule of a compound contains. Note: Ionic compounds are generally crystalline solids with high melting points. Other compounds, however, have very different properties.
Why does Alex’s equation better represent the reaction?
Answer : it has been tested
Explanation:
i took the test
If a number has the units g/L then its
A) a number we are not going to use at all.
B) an imaginary unit that we are not going to use.
C) creating a relationship between mass and volume
D) a relationship between volume and distance.
Answer:
C) creating a relationship between mass and volume
g/L
g or gram is mass
L or Litres is for volume
Help
what is isotopes
which statement describes how vapor pressure occurs? (1 point)
a) Some molecules of a substance have high enough kinetic energy to vaporize. These molecules exert
pressure on the substance.
b) Some molecules of a substance have low enough kinetic energy to melt. These molecules exert pressure on the substance
c) Some molecules of a substance have low enough kinetic energy to vaporize. These molecules exert
pressure on the substance.
d) Some molecules of a substance have high enough kinetic energy to melt. These molecules exert pressure on the substance
Some molecules in a substance have a high kinetic energy hence they are able to convert into vapor. These molecules exert pressure on the liquid surface.
We know that the molecules that compose matter are in constant random motion. The kinetic energy of all the molecules in the liquid are not the same. The molecules at the surface of the liquid posses more kinetic energy than the molecules below.
Some molecules of a substance have high enough kinetic energy to vaporize. These molecules exert pressure on the substance.
Learn more: https://brainly.com/question/25273232
Answer:
Some molecules of a substance have high enough kinetic energy to vaporize. These molecules exert pressure on the substance.
Explanation:
How does lemon juice stop an apple from turning brown?
The most recent model of an atom is the_____.
Points: 67
Answer:
answer is electron cloud model
The speed at which a chemical reaction proceeds is called
Answer:
Answer: Reaction Rate
Explanation:
reaction rate, in chemistry, the speed at which a chemical reaction proceeds. It is often expressed in terms of either the concentration (amount per unit volume) of a product that is formed in a unit of time or the concentration of a reactant that is consumed in a unit of time.
3) The nucleus in a photograph of a cell measures 3 mm across. If the magnification in the photograph is x 500, what is the actual size of the nucleus?
Answer:
1500mm oqkwndbdjdhdndjdd
A sample of tin (Cp = 0. 227 J/g•°C) is placed in a freezer. Its temperature decreases from 15. 0°C to â’10. 0°C as it releases 543 J of energy. What is the mass of the sample? Round your answer to three significant figures. G.
Taking into account the definition of calorimetry, the mass of the sample is 478.41 grams.
Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.
Sensible heat is defined as the amount of heat that a body absorbs or releases without any changes in its physical state (phase change).
So, the equation that allows to calculate heat exchanges is:
Q = c× m× ΔT
where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.
In this case, you know:
Q= -543 J because the energy is releasesc= 0.227 [tex]\frac{J}{gC}[/tex]m= ?ΔT= Tfinal - Tinitial= 10 C - 15 C= -5 CReplacing:
-543 J= 0.227 [tex]\frac{J}{gC}[/tex]× m× (-5 C)
Solving:
[tex]m=\frac{-543 J}{0.227 \frac{J}{gC}x(-5 C)}[/tex]
m=478.41 grams
In summary, the mass of the sample is 478.41 grams.
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brainly.com/question/11586486?referrer=searchResults brainly.com/question/24724338?referrer=searchResultsPart 1: Name the type of chemical reaction that occurs when magnesium chloride
solution (MgCl2) reacts with sodium carbonate solution (Na2CO3).
Part 2: Explain why aluminum (AI) would react with copper chloride (CuCl2) but not with
magnesium chloride (MgCl2).
Mg is ahead of Al in the electrochemical series and more reactive than Al hence Al does not react with MgCl2.
A chemical reaction is said to have occurred when new substances are formed. The reaction between magnesium chloride solution and sodium carbonate solution is a double decomposition reaction since the cations exchange anion partners in the product;
MgCl2(aq) + Na2CO3(aq) ------> MgCO3(s) + 2NaCl(aq)
We must note that a single replacement reaction depends on the relative positions of metals in the electrochemical series. Al can react with CuCl2 because Al is more reactive than copper and ahead of Cu in the electrochemical series. On the other hand, Mg is ahead of Al in the electrochemical series and more reactive than Al hence Al does not react with MgCl2.
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True or False. When light passes from one medium to another the speed changes.
Answer:
Its actually true
Explanation:
Your Welcome Canada,
OH YEAH!!!!!!
Answer:
The correct answer is "True".
Explanation:
I hope this helps!
do Plants and animals create energy the same way?
Answer:
Yes
Step By Step Explanation:
Plants extract energy from food molecules the same way animals do — by cellular respiration.
Most, if not all plants are producers, and they make their own food using sunlight and raw materials, through a process called "photosynthesis". ... Plants get their energy in form of starch whereas animals get it in form of glycogen. Animals get their energy from the food they eat. Animals depend on other living things for food. Some animals eat plants while others eat other animals. This passing of energy from the sun to plants to animals to other animals is called a food chain.
Animals obtain energy from the food they consume, using that energy to maintain body temperature and perform other metabolic functions. Glucose, found in the food animals eat, is broken down during the process of cellular respiration into an energy source called ATP.
Hopes This Helps
which of the following atom could reside in the same group? Explain your answer
What is the chemical composition of dry ice?
Answer:
Dry ice is the solid form of carbon dioxide (CO 2), a molecule consisting of a single carbon atom bonded to two oxygen atoms. Dry ice is colorless, odorless, and non-flammable, and can lower the pH of a solution when dissolved in water, forming carbonic acid (H 2 CO 3).
Explanation: i asked my teacher and this was her response.
The last layer in layered design is _____________. Object Process None of the options Atoms Sub process
The last layer in the layered design is system layer so none of the above is the correct option.
Robotic Process Automation is a software technology that make use of some programs of computer to copy or mimic the behaviors of human when it has access with them. They been use effectively and ensure the work is perfectly done.
There are layers in the Robotic process automation but the last layer is System layer.
They can handle high volume of tasks.
The lowermost layer is associated with individual screen interactions. The lowermost layer in the layered design of Robotic process automation is the component layer or system layer . The Robotic Process Automation and this form technology is in robots creation.
Therefore, The last layer in layered design Is System layer so none of the above is the correct option.
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Mass is the amount of matter in an object, but
weight is
A. the size of the matter.
B. the amount of space matter takes up.
C. the shape of the matter.
D. gravity's pull on the matter.
Answer: is equal to the gravitational pull on an object
Explanation:
how much heat is released when 32g of water cools from 46°C and freezes
The amount of heat released when 32g of water cools from 46°C and freezes is 6182.4 J
Heat: This is a form of energy that brings about the sensation of warmth. The S.I unit of heat is Joules (J)
⇒ Formula:
Q = cm(t₂-t₁).................. Equation 1⇒ Where:
Q = amount of heat releasedc = specific heat capacity of waterm = mass of watert₁ = Initial temperaturet₂ = Final temperatureFrom the question,
⇒ Given:
m = 32 g = 0.032 kgt₁ = 46 °Ct₂ = 0 °C (Freezing point)c = constant = 4200 J/kg.°C⇒ Substitute these values into equation 1
Q = 0.032(4200)(0-46)Q = -6182.4 JNote: The negative sign tells that heat is released and as such can be ignored.
Hence, The amount of heat released is 6182.4 J
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Which materials are used to make concrete select all that apply
Answer:
cement air water sand and gravel
Explanation:
Answer:
Explanation:
The principal ingredients that make up the concrete mix are: cement, fine aggregate, coarse aggregate, water, chemical admixtures, and mineral admixtures.
