Answer:
1.what I observe.
Explanation:
The dependent variable in an experiment is what is being observed in the experimental procedure.
This variable is the one that is closely tied to the effects originating from changing the independent variables.
Independent variables are the ones that cause the observation being studied. The effects produced and then studied are the dependent variables.Using charge to describe an atom
Answer:
this atom has nine electrons
Forty milliliter of a liquid has a mass of 80 grams. What is the density of this substance?
Answer:
2.00g/ml
Explanation:
If water has a density of 1.00g/ml, and theres
40ml of it, it would weigh 40g
The substance is twice as dense as water, making its density 2.00g/ml
All good experiments should be...
liquid containing a mixture of neon and xenon was cooled down. One gas solidified at -249 °C and the other at –112 °C. Identify which noble gas solidified at -249 °C and which at -112 °C. Justify your answer.
Answer:
The noble gases (Group 18) are located in the far right of the periodic table and were previously referred to as the "inert gases" due to the fact that their filled valence shells (octets) make them extremely nonreactive. The noble gases were characterized relatively late compared to other element groups.
The History
The first person to discover the noble gases was Henry Cavendish in the late 180th century. Cavendish distinguished these elements by chemically removing all oxygen and nitrogen from a container of air. The nitrogen was oxidized to NO2 by electric discharges and absorbed by a sodium hydroxide solution. The remaining oxygen was then removed from the mixture with an absorber. The experiment revealed that 1/120 of the gas volume remained un-reacted in the receptacle. The second person to isolate, but not typify, them was William Francis (1855-1925). Francis noted the formation of gas while dissolving uranium minerals in acid.
Argon
In 1894, John William Strutt discovered that chemically-obtained pure nitrogen was less dense than the nitrogen isolated from air samples. From this breakthrough, he concluded that another, unknown gas was present in the air. With the aid of William Ramsay, Strutt managed to replicate and modify Cavendish's experiment to better understand the inert component of air in his original experiment. The researchers' procedure differed from the Cavendish procedure: they removed the oxygen by reacting it with copper, and removed the nitrogen in a reaction with magnesium. The remaining gas was properly characterized and the new element was named "argon," which originates from the Greek word for "inert."
Helium
Helium was first discovered in 1868, manifesting itself in the solar spectrum as a bright yellow line with a wavelength of 587.49 nanometers. This discovery was made by Pierre Jansen. Jansen initially assumed it was a sodium line. However, later studies by Sir William Ramsay (who isolated helium on Earth by treating a variety of rare elements with acids) confirmed that the bright yellow line from his experiment matched up with that in the spectrum of the sun. From this, British physicist William Crookes identified the element as helium.
Neon, Krypton, Xenon
These three noble gases were discovered by Morris W. Travers and Sir William Ramsay in 1898. Ramsay discovered neon by chilling a sample of the air to a liquid phase, warming the liquid, and capturing the gases as they boiled off. Krypton and xenon were also discovered through this process.
Radon
In 1900, while studying the decay chain of radium, Friedrich Earns Dorn discovered the last gas in Group 18: radon. In his experiments, Dorn noticed that radium compounds emanated radioactive gas. This gas was originally named niton after the Latin word for shining, "nitens". In 1923, the International Committee for Chemical Elements and International Union of Pure Applied Chemistry (IUPAC) decided to name the element radon. All isotopes of radon are radioactive. Radon-222 has the longest half-life at less than 4 days, and is an alpha-decay product of Radium-226 (part of the U-238 to Pb-206 radioactive decay chain).
The Electron Configurations for Noble Gases
Helium 1s2
Neon [He] 2s2 2p6
Argon [Ne] 3s2 3p6
Krypton [Ar] 3d10 4s2 4p6
Xenon [Kr] 4d10 5s2 5p6
Radon [Xe] 4f14 5d10 6s2 6p
Explanation:
If an atom has a neutral charge, it must have
Answer:
Proton or electron. I think, not sure.
Explanation:
A proton and an electron have an equal amount but an opposite type of charge. Thus, if an atom contains equal numbers of protons and electrons, the atom is described as being electrically neutral.
eletrons I'm pretty sure
is a renewable resource used for the generation of electricity.
A. Natural gas
B. Coal
C. Petroleum
O D. Biomass
Answer:
its natural gas because i had something like this
Explanation:
The renewable energy sources, such as biomass, geothermal resources, water, wind, etc. are called the natural resources. These can be converted into clean and usable energy. The correct option is D.
What is Renewable energy?The energy which is derived from the natural sources which are replenished at a higher rate than they are consumed is defined as the Renewable energy. The renewable energy generating produce lower emissions than burning the fossil fuels.
The word biomass refers to the organic plant matter which is converted into fuel and used as an energy source. The biomass fuel is considered as an important renewable and sustainable source of energy. It is used for the production of electricity.
The organic materials like wood, agricultural wastes, etc. acts as the excellent sources to produce biomass fuel. It is possible to burn the biomass fuel directly and later converted into methane and ethanol biofuels.
Thus the correct option is D.
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magnesium: atomic number
Answer:
Magnesiums atomic number is 12
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Which is an example of a current research focus in chemistry?
A. applying gene therapy to treat certain diseases
B. using hook-and-loop tape in the clothing industry
C. developing smoke detectors for common use
D. studying coal combustion as an energy source
Answer:
b is the correct answer
do not trust answer one
Explanation:
The equilibrium constant _____________. For an ___________ reaction, heat is a reactant. An increase in temperature and heat favors the ____________ reaction and the value of K c _____________.
Answer:
The equilibrium constant change. For an endothermic reaction, heat is a reactant. An increase in temperature and heat favors the forward reaction and the value of Kc increases.
Explanation:
Hello.
In this case, regarding reactions in equilibrium in which heat is a reactant as those exemplified by:
[tex]Heat+Reactants \rightleftharpoons Products[/tex]
We infer that the heat of reaction is positive since the reactants have more energy in their ground state than the products making them endothermic. Moreover, since the Le' Chatelier's principle states that increasing the reaction temperature in endothermic reactions, the forward reaction (towards products) is favored because endothermic reactions absorb heat in the form temperature raise, the required statement is:
The equilibrium constant change. For an endothermic reaction, heat is a reactant. An increase in temperature and heat favors the forward reaction and the value of Kc increases.
Regards.
Answer:
The equilibrium constant increases. For an endothermic reaction heat is a reactant. An increase in temperature and heat favours the forward reaction and the value of KC increases.
Explanation:
Similar properties recur periodically when elements are arranged according to increasing atomic number is the statement of the ______. g
Answer:
Modern periodic law
Explanation:
There are many ways of stating the modern periodic law. Generally, the modern periodic law states that the properties of elements are a periodic function of their atomic numbers. That means, similar properties recur periodically when elements are arranged according to increasing atomic number.
Two scientists were largely responsible for our present day understanding of the modern periodic law, they are, Mendeleev and Moseley. Their work laid the foundation for the periodic table in its current form.
5. What gases was produced from decomposing hydrogen peroxide? What non-gaseous product formed from the reaction
Answer:
H2O
Explanation:
The equation for the decomposition of hydrogen peroxide is shown below;
2H2O2(l)-----> 2H2O(l) + O2(g)
Hence, the decomposition of H2O2 yields oxygen gas and water. Water is a non gaseous product of the reaction as clearly seen in the equation above.
How many grams of Cl are in 31.2g CF2Cl2
Answer:
Mass = 42.6 g
Explanation:
Given data:
Mass of CF₂Cl₂ = 31.2 g
Mass of Cl₂ = ?
Solution:
Number of moles of CF₂Cl₂ = mass/molar mass
Number of moles = 31.2 g/121 gmol
Number of moles = 0.3 mol
1 mole of CF₂Cl₂ contain 2 moles of Cl atom.
0.3 mol × 2 = 0.6 mol
Mass of Cl₂:
Mass = number of moles × molar mass
Mass = 0.6 mol × 71 g/mol
Mass = 42.6 g
Which element contains one set of paired and three unpaired electrons in its fourth and outer main energy level?
Explanation:
Phosphorus (P) because of the 5 valence electrons total, 3 of them are in the 3p sublevel, and according to Hund's rule, they "single-fill" each orbital first.
How many moles of methane are produced when 48.1 moles of carbon dioxide gas react with excess hydrogen gas?
What does a dissolved salt look like?
Answer:(trick question) once the salt has dissolve in the water it is no longer visible
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How many grams of NaCl are needed to prepare 50.0 grams of a 35.0% salt solution?
17.5 grams of NaCl are needed to prepare 50.0 grams of a 35.0% salt solution.
What is Solution?
A solution is a homogenous mixture composed of two or more substances. In a solution, the components are evenly distributed throughout the mixture, resulting in a uniform appearance and properties.
The substance that is present in the largest amount is called the solvent, while the other substances present in lesser amounts are called solutes. When the solute dissolves in the solvent, the resulting mixture is called a solution.
To calculate the grams of NaCl needed to prepare a 35.0% salt solution, we can use the formula:
grams of NaCl = (percent salt / 100) x grams of solution
grams of NaCl = (35.0 / 100) x 50.0
grams of NaCl = 0.35 x 50.0
grams of NaCl = 17.5
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How many atoms are in caco4
Answer: 6
Explanation:
When nitrogen, oxygen, fluorine, sodium, magnesium and aluminum ionize, they all will have:
a. different electron configuration from each other.
b. an unchanged electron configuration.
c. the same charge.
d. the same electron configuration (isoelectronic) as neon.
[Definition: The word isoelectronic means that when you write out the electron configuration they are the same. An exam would be He and Li whereby both of them have 2 electrons and therefore they are both are 1s2 in their electron configurations.]
Answer: d. the same electron configuration (isoelectronic) as neon.
Explanation:
Isoelectronic species are defined as the molecules which have the same number of electrons.
Atomic number of nitrogen is 7 and thus has 7 electrons. Nitrogen has electronic configuration of 2,5 and thus can gain 3 electrons and thus [tex]N^{3-}[/tex] will have electronic configuration of 2,8 ( same as that of neon)
Atomic number of oxygen is 8 and thus has 8 electrons. Oxygen has electronic configuration of 2,6 and thus can gain 2 electrons and thus [tex]O^{2-}[/tex] will have electronic configuration of 2,8 ( same as that of neon)
Atomic number of flourine is 9 and thus has 9 electrons. Flourine has electronic configuration of 2,7 and thus can gain 1 electron and thus [tex]F^{-}[/tex] will have electronic configuration of 2,8 ( same as that of neon)
Atomic number of sodium is 11 and thus has 11 electrons. Sodium has electronic configuration of 2,8,1 and thus can lose 1 electron and thus [tex]Na^{+}[/tex] will have electronic configuration of 2,8 ( same as that of neon)
Atomic number of magnesium is 12 and thus has 12 electrons. Magnesium has electronic configuration of 2,8,2 and thus can lose 2 electrons and thus [tex]Mg^{2+}[/tex] will have electronic configuration of 2,8 ( same as that of neon)
Atomic number of aluminium is 13 and thus has 13 electrons. Aluminium has electronic configuration of 2,8,3 and thus can lose 3 electrons and thus [tex]Al^{3+}[/tex] will have electronic configuration of 2,8 ( same as that of neon)
Explain how a hurricane poses a threat to life and the biosphere. Use complete sentences.
Answer:
A hurricane can cause extreme damage to the biosphere and the geosphere. A hurricane can leave water standing therefore sinking itself into the geosphere. The biosphere can be permanently effected because it can kill, injure, and destroy the biosphere and what the biosphere creates (buildings, parks).
Explanation:
Our universe is made up of at least a
It took 70 seconds for 280cm³ of nitrogen to diffuse through a membrane. If Carbon(IV)Oxide is allowed to diffuse through the same membrane, how long will it take the gas to do so ?
Answer:
t = 125.3 seconds
Explanation:
Molar mass of CO2 = 12+2(16) = 66
Molar mass of N2 = 2(14)= 28
rate of diffusion of N2 = volume/ time = 280cm³/70s
= 4cm³/s
let rate of CO2 = rate of diffusion of CO2 = volume/time
= 400/t
Using Graham's law of diffusion,
rN2/rCO2 = √M(CO2)/M(N2)
4/400/t =√44/28 = 4t/400= √11/7
t/100 = 1.253 , t= (100)(1.253)
t = 125.3 seconds
hence it takes CO2 125.3 seconds to diffuse through the membrane
Which of the following characteristics will not help which of the following characteristics WILL NOT help you tell whether two solids are the same or are different substances?
A. Color
B. Hardness
C. Shape
D. Melting point
What are the conjugate base and conjugate acid for HSO4−? What is the term used to describe species that can behave as either an acid or a base, depending on the chemical environment?
Answer:
Conjugate acid- H^+
Conjugate base- SO4^2-
Terminology- Amphoteric
Explanation:
Consider the equilibrum shown below;
HSO4^-(aq)<-------> H^+(aq) + SO4^2-(aq)
Hence, When HSO4^- is dissolved in aqueous solution, it's conjugate acid is H^+ and it's conjugate base is SO4^2- as shown in the equation above.
If a substance behaves both as an acid and as a base, then the substance is Amphoteric in nature.
The conjugate acid [tex]H^+[/tex]and base [tex]SO4^2-[/tex] and the term would be Amphoteric.
Conjugate acid-
What is Amphoteric?Amphoteric is described as the term employed to denote a substance that possesses the characteristics of both an acid, as well as, a base.
Given equilibrium:
[tex]HSO4^-(aq)[/tex] → [tex]H^+(aq) + SO4^2-(aq)[/tex]
Therefore, the dissolution of [tex]HSO4^-[/tex] in water leads to the display acid that is conjugate [tex]H^+[/tex] and the conugate base [tex]SO4^2-[/tex].
In case, the properties of both are reflected, it shows amphoteric nature.
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C. Where is sugar removed from the blood?
and how can you tell
Answer:During absorption and digestion, the carbohydrates in the food you eat are reduced to their simplest form, glucose. Excess glucose is then removed from the blood, with the majority of it being converted into glycoge, the storage form of glucose, by the liver's hepatic cells via a process called glycogenesis
Explanation:
Draw molecules that satisfy the following prompts:
1. All molecules must have a minimum of 12 Carbon atoms and exactly 3 heteroatoms (not carbon or hydrogen atoms).
2. You may not use the same molecule twice for any parts of this question.
4. You do not need to look up solubility information, but the answers must be reasonable (supported by the concepts that we have discussed). Also, the structures must be reasonable (improper structures, e.g. carbon with 5 bonds or oxygen with one bond and no charge, will not receive any credit).
a. Draw two non-charged molecules that will be separated once they are placed in a separatory funnel that contains 2.5 M HCl(aq) and dichloromethane.
b. Draw two non-charged molecules that will be separated once they are placed in a separatory funnel that contains 2.5 M NaOH(aq) and dichloromethane.
c. Draw two non-charged molecules that will be separated using neutral water and dichloromethane and in a separatory funnel.
Answer:
see images attached
Explanation:
Here we are trying to perform solvent extraction. In solvent extraction, there must be an aqueous phase and an organic phase.
One of the species to be separated is extracted in greater concentration in the aqueous phase while the other is extracted in greater concentration in the organic phase.
The phase into which each specie is extracted depends on the nature of the specie.
Two structures are shown in the images attached that will be separated by the methods shown in (a) (b) (c) in the question
When a helium balloon rises in the air, it expands. If the volume of the balloon doubles, what happens to the density of the helium inside it?
a.The density decreases by half
b.The density doubles
c.The density triples
d.The density stays the same
In which Earth system does the rock cycle take place?
cryosphere
atmosphere
geosphere
biosphere
Answer:
geosphere
Explanation:
geo means rocks this is the area
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How does a circuit with a 1.5-volt battery compare to a circuit with a 9-volt battery?
which of the following Ph levels would indicate the weakest base?
15
8
6
2
Answer:
8
Explanation:
7 is neutral any anything above it is basic and anything below is acidic which means 8 would be the lowest base
Answer:
The pH of a weak base falls somewhere between 7 and 10.
Explanation:
Like weak acids, weak bases do not undergo complete dissociation; instead, their ionization is a two-way reaction with a definite equilibrium point
Which of the following substances will form a base when dissolved in water?
Question 14 options:
A)
HCl
B)
HBr
C)
KOH
D)
SO2
Answer:
Its D) SO2
Explanation
Did the test