How many valence electrons does Bromine have?
Answer:
7
Explanation:
Answer:
Bromine has 7 valence electrons.
Explanation:
Bromine is in group 7 or 17, so it has 7 valence electrons use the Lewis structure for more help.
2 Points
Which of these is a benefit of using cotton grocery bags?
Answer:
What are the options given?
Answer:They can be used over or 100 times without tear.
Explanation: A P E X
Why did Thomson’s results from experimenting with cathode rays cause a big change in scientific thought about atoms?
A.His results gave people a picture of what atoms look like for the first time.
B.His results gave the first clues that atoms could be created and destroyed.
C.His results gave the first experimental evidence that matter is made up of atoms.
D.His results gave the first evidence that atoms were made up of smaller particles.
Answer:
D, because he discovered electrons
Explanation:
His results gave the first evidence that atoms were made up of smaller particles.
When a chemical reaction occurs, _____.
a phase change takes place
the physical and chemical properties of the products are different from the reactants
the physical and chemical properties of the reactants are the same as the properties of the products
the compounds can be separated by physical means
Answer: When a chemical reaction occurs, _____.
a phase change takes place
the physical and chemical properties of the products are different from the reactants
Explanation:
A chemical change is like dynamite exploding or iron rusting. It's an actual change in the chemical makeup resulting in a new product
A chemical reaction results in the production of new substances with physical and chemical properties that are different from the reactants, unlike a physical change which does not alter the molecular structure of the substance.
Explanation:When a chemical reaction occurs, the physical and chemical properties of the products are different from the reactants. A chemical reaction involves a change in the composition of the substances in question where bonds between atoms are broken and/or formed, resulting in the production of new substances. These new products exhibit different physical and chemical properties such as melting point, color, taste, etc. This is in contrast to a physical change which only affects the appearance or form of a substance without altering its molecular structure. Chemical changes are often more difficult to reverse than physical changes. For example, combining hydrogen and oxygen to produce water is a chemical change because it results in the formation of a new substance with different properties than those of the individual reactants.
Determine the oxidation STATE of S in LiSO4
Answer:
Element: S O
Oxidation number: +6 -2
Explanation:
Which substance contains bonds that involve a transfer of electrons from one atom to another
1. For each of the molecules below, determine the electron geometry, molecule geometry, and bond
angles.
a. CC14 (4 Cl atoms, no lone pairs on C)
b. PF3 (3 Fatoms, 1 lone pair on P)
c. OF2 (2 F atoms, 2 lone pairs on O)
d. 13. (2 1 atoms and 3 lone pairs on central I)
e. A molecule has 2 double bonds on the central atom and no lone pairs. Predict the molecule geometry. What do you think the bond angles would be?
Answer:
CCl4- tetrahedral bond angle 109°
PF3 - trigonal pyramidal bond angles less than 109°
OF2- Bent with bond angle much less than 109°
I3 - linear with bond angles = 180°
A molecule with two double bonds and no lone pairs - linear molecule with bond angle =180°
Explanation:
Valence shell electron-pair repulsion theory (VSEPR theory) helps us to predict the molecular shape, including bond angles around a central atom, of a molecule by examination of the number of bonds and lone electron pairs in its Lewis structure. The VSEPR model assumes that electron pairs in the valence shell of a central atom will adopt an arrangement which tends to minimize repulsions between these electron pairs by maximizing the distance between them. The electrons in the valence shell of a central atom are either bonding pairs of electrons, located primarily between bonded atoms, or lone pairs. The electrostatic repulsion of these electrons is reduced when the various regions of high electron density assume positions as far apart from each other as possible.
Lone pairs and multiple bonds are known to cause more repulsion than single bonds and bond pairs. Hence the presence of lone pairs or multiple bonds tend to distort the molecular geometry geometry away from that predicted on the basis of VSEPR theory. For instance CCl4 is tetrahedral with no lone pair and four regions of electron density around the central atom. This is the expected geometry. However OF2 also has four regions of electron density but has a bent structure. The molecule has four regions of electron density but two of them are lone pairs causing more repulsion. Hence the observed bond angle is less than 109°.
Which of the following air fronts does not move?
a Occluded front
b Cold front
c Stationary front
d Warm front
can someone answer this
Answer:
Explanation:
10 N right
Natural gas is a relatively clean burning fuel, meaning it produces less _________ than oil or coal.
Answer:
Burning natural gas
Explanation:
hope this helps mark me as brainliest pls :)
Natural gas is a relatively clean burning fuel, meaning it produces less burning than oil or coal.
What is natural gas ?Methane makes up the majority of natural gas, which is a combination of gaseous hydrocarbons that also contains minor quantities of other higher alkanes. Typically, trace gases including helium, nitrogen, hydrogen sulfide, and carbon dioxide are also present in low concentrations.
When burning natural gas for energy, less carbon dioxide ( CO₂ ) and almost all other air pollutants are released into the atmosphere than when burning coal or petroleum products to provide the same amount of energy.
One of the cleanest and safest fuels is natural gas. In comparison to other fossil fuels, it produces less pollution. When natural gas is consumed, it mostly emits water vapor and carbon dioxide, which are also gases that people exhale.
Thus, Natural gas is a relatively clean burning fuel, meaning it produces less burning than oil or coal.
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In terms of bond energies of the chemicals involved, why can hydrogen can be used as a fuel?
Answer:
see below
Explanation:
Hydrogen reacting with oxygen to generate water produces a relatively large amount of thermal energy. As requested and in terms of bonding energies, a Hydrogen - Oxygen fuel cell reaction could be illustrated as follows...
H - H + 1/2(O = O) => H - O - H
ΔHb: 1mol(-436Kj/mol) 1/2mol(498 Kj/mol) 1mol(-463 Kj/mol)
= -436Kj = -249Kj = -926Kj
ΔH(Rxn) = ∑ΔH(Products) - ∑ΔH(reactants)
= [(-926kj)] - [(-436Kj) + (-249Kj)]
= (-926 + 436 + 249)Kj = -241Kj (=> which is the Standard Heat of Formation of Water => See Thermo Tables in text appendix).
This means, on reaction of Hydrogen and Oxygen, 241Kj energy is released by exothermic process. The challenge now, is to direct this 241Kj of energy into a material substance so as to generate useful outcomes (work).
Now one should understand that the source of the energy in this problem is from the hydrogen - oxygen reaction, however, there are other mechanisms and reactions that generate thermal energy. Hydrogen fuel cell is but one.
So, now what does one do with the thermal energy generated in the fuel cell reaction. That is, what application would be needing 241Kj of energy per mole water formed? Consider two needed (hypothetical) applications => 1. to boil water and the other 2. to warm a tub of bathwater.
Our physics friends tell us that the amount of thermal heat used is related to the mass of substance receiving the heat and the resulting temperature change accompanying the transfer of thermal energy by the following equation ...
q = mcΔT where q = thermal energy. m = mass, c = specific heat & ΔT = Temperature change.
Given that both applications will receive the same amount of thermal energy ( => 241Kj) the question is reduced to how much mass would be needed to heat the water to boiling for application 1 vs amount of water to moderately heat water for a bath.
Application 1 (Boiling water) => 241Kj energy would only need a small quantity of water to achieve a high enough temperature to reach boiling point where as, Application 2 (Warming bath water) => 241Kj energy would be applied to a much larger quantity of water to limit the heating effect to a moderate temperature level.
In summary, the hydrogen-oxygen fuel cell reaction produces thermal energy => the thermal energy is directed into a mass of substance that is then heated to a needed temperature level to perform a functional service. The services derived from the H/Oxy rxn are, in essence, the utility of the process as a fuel. :-)
Addendum => The Hydrogen Electrochemical fuel cell process is the same except the process is galvanic in nature but still generates the same amount of thermal energy which is translated directly into electrical energy for needed applications.
PLEASE HELP LAST QUESTION
what would happen if NO were added to N2(g)+O2(g)->2NO(g) at equilibrium?
a. More NO would form
b. More N2 and O2 would form
c. Keq would increase
d. Keq would decrease
Balance the equation Rb + Au2O3
Answer : The balanced chemical reaction will be:
[tex]6Rb+Au_2O_3\rightarrow 2Au+3Rb_2O[/tex]
Explanation :
As per question, when rubidium react with gold oxide then it gives rubidium oxide and gold.
This reaction is a single replacement reaction in which more reactive element displaces the least react element from its solution.
The balanced chemical reaction will be:
[tex]6Rb+Au_2O_3\rightarrow 2Au+3Rb_2O[/tex]
How much energy would need to be input to completely boil 17.3 moles of ice starting at 0 degrees * C and going to 100°C?
(H=40.5 kJ/mol ; H = 6.0kJ / (mol) ; specific
Answer:
[tex]Q = 934.911\,kJ[/tex]
Explanation:
The energy needed to boil 17.3 moles of ice is:
[tex]Q = (17.3\,mol)\cdot \left[\left(40.5\,\frac{kJ}{mol} \right)+ \left(\frac{4.186}{1000}\,\frac{kJ}{g\cdot ^{\circ}C} \right)\cdot \left(\frac{18.015\,g }{1\,mol} \right)\cdot (100^{\circ}C-0^{\circ}C)+\left(6\,\frac{kJ}{mol}\right)\right][/tex][tex]Q = 934.911\,kJ[/tex]
A sample of gas at STP has a volume of 5.23 L. If the gas volume is changed to 3.45 L at 293 K, calculate the new pressure of the gas.
Answer: P=1.63atm
Explanation:
Stp means standard temperature and pressure
Standard temperature =273k
Standard pressure =1atm
Using the formula
P1V1/T1=P2V2/T2
P1= 1atm
V1=5.23L
T1=273k
P2=?
V2=3.45L
T2=293k
Substitute the values
1×5.23/273=p2×3.45/293
Cross multiply
293×1×5.23=p2×3.45×273
1532.39=941.85p2
P2=1532.39/941.85
P2=1.627
P2=1.63atm
Why do the nuclides that are used as radiotracers have short half-lives?
Step 3: Measure the Reaction Rate at 40°C
Using tongs, place the 250 ml beaker on the hotplate.
Temperature of the water:
°C. Reaction time:
seconds DONE
Answer:
Temperature of water is 40
Reaction Time is 26.3
Explanation:
Hope this helps
A reaction's rate can be used as a valuable diagnostic tool. The temperature of water is 40° C, and the rate of reaction is 26.3.
What is rate of reaction ?The speed at which a chemical reaction occurs is known as the reaction rate or rate of reaction. It is proportional to the rise in product concentration per unit time and the fall in reactant concentration per unit time. Reaction times might differ significantly.
We may devise strategies to increase production by learning how quickly things are created and what slows down reactions. This knowledge is necessary for the industrial production of various chemicals, such as fertilizers, medications, and home cleaners.
The change in a reactant or product's concentration over time is what is referred to as the rate of a chemical reaction. Concentration is measured in moles per liter, or molar, and time is measured in seconds. Therefore, we use molar per second to indicate the pace of a chemical reaction.
Thus, the temperature of water is 40° C, and the rate of reaction is 26.3.
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what type of energy does a saxophone player have and what energy does it turn into
50 + 25 pts 75 for right answer
Some physical properties of matter include:
density
color
reactivity
luster
abundance
taste
source
Answer:
soe are appearance, texture, color, odor, melting point, boiling point, density, solubility, polarity, and many other
Explanation:
Which best describes the formation of metamorphic rock?
They are formed through the cooling and hardening of magma or
lava, both below Earth's surface or on Earth's surface as volcanic
rocks.
They are formed by deposited sediment, usually at the bottom of
lakes and oceans, that is compressed over time into solid layers of
rock
They are formed as extreme weather elements, like tornadoes and
floods, break down mountains and other rock landforms into smaller
pieces.
They can be formed from any of the three rock types, withstanding
high temperatures and pressures, and forming new minerals without
melting.
D)
Answer:
D)They can be formed from any of the three rock types, withstanding
high temperatures and pressures, and forming new minerals without
melting.
Explanation:
The metamorphic rocks are formed through cooling and hardening of magma or lava, both below Earth's surface or on Earth's surface as volcanic rocks. Thus the correct option is A.
What is metamorphic rock?The type of rock which are generated when rocks are subjected to many physical changes such as heat, pressure and different chemical reactivity over a long period of time are called metamorphic rocks.
The process of metamorphism makes the rocks as chemically modified and recrystallized. This process does not melt the rocks, but it transforms the rocks into dense and compact rocks.
The common metamorphic rocks are marble, schist, phyllite, etc. The action of pressure and temperature can even change the metamorphosed rocks into new types. They can be even folded and squished.
The term meta means change and morph means form. This rocks are formed as a result of geological process such as magma intrusions.
Thus the correct option is A.
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C2H2 + 2H2 → C2H6
How many moles of hydrogen are needed to produce 13.78 mol of ethane?
Answer:
27.56 moles
Explanation:
Answer:
27.56 mol ans C)
Explanation:
Which statement is true about a polyatomic ion?
It forms metallic bonds with other ions.
It forms covalent bonds with other ions.
It is made of atoms that are covalently bonded together.
It has a charge that is distributed over part of the entire unit.
*
Answer:
It is made of atoms that are covalently bonded together.
Explanation:
For example the carbonate ion CO3++.
The carbon and oxygen atoms are held together by covalent bonds.
Answer:
"It is made of atoms that are covalently bonded together." (C)
Explanation:
Polyatomic ion is made of three atoms that are covalently bonded together
Edg. 2020 :)
Which of these is a problem with using nuclear energy?
A.
It is very expensive to use.
B.
It is a non-renewable energy source.
C.
There aren't enough qualified technicians.
D.
We don't have a way to contain the radioactive waste produced.
Answer:
D
We don't have a way to contain the radioactive waste produced.
Explanation
Nuclear waste is non disposable and takes millions of years to biodegrade and lose it radio activeness
0.5 moles of any gas is at STP, it will occupy how many LITERS of volume?
Answer: 500L
Explanation:
No of moles= volume× molarity/1000
No of moles =0.5moles
Volume=?
Molarity of a gas at stp = 1M
Stp means standard temperature and pressure
No of moles = volume ×molarity/1000
Substitute the values
0.5=volume×1/1000
Cross multiply
Volume = 1000×0.5
Volume = 500L
The volume is 500L
A student needed to make 100.0 mL of 0.20M NaOH solution. How many grams of sodium hydroxide does the student need to weigh out
Answer:
0.08 g
Explanation:
100.0 mL = 0.10 L
Multiply the volume by the molarity to find moles.
0.10 L × 0.20 M = 0.002 mol
Convert moles to grams.
0.002 mol × 40 g/mol = 0.08 g
Final answer:
To prepare 100.0 mL of 0.20M NaOH solution, a student needs to weigh out 0.80 grams of NaOH, using the molar mass of NaOH and the desired solution volume and concentration.
Explanation:
Calculating the Mass of NaOH Needed for 0.20M Solution
To determine the mass of sodium hydroxide (NaOH) necessary to prepare a 100.0 mL of 0.20M NaOH solution, we have to follow multiple steps:
Calculate the number of moles of NaOH required using the formula Molarity (M) = Moles of solute (mol) / Volume of solution in liters (L).
Convert the volume from mL to L, since the molarity formula requires volume in liters.
Use the molar mass of NaOH to convert moles to grams.
First, we calculate the moles needed:
0.20 mol/L * 0.100 L = 0.020 mol NaOH
Next, we determine the mass of NaOH using its molar mass:
Molar mass of NaOH = 40.00 g/mol
Mass of NaOH = Moles * Molar mass
Mass of NaOH = 0.020 mol * 40.00 g/mol = 0.80 g NaOH
Therefore, the student would need to weigh out 0.80 grams of NaOH to prepare a 100.0 mL of 0.20M NaOH solution.
Please help I’m being timed In many thermodynamically favored reactions, the total bond energy of the products is lower than the total bond energy of the reactants. Therefore, thermodynamically favored reactions are often
A) exothermic
B) endothermic
C) conducted in warm conditions
D) conducted in cold conditions
Calculate the number of atoms in 4.8 dm^3 of neon gas at rtp
No of atoms in 4.8 dm³ of neon gas is determined in the following way.
Explanation:
We have given
Neon Gas=4.8dm³
At STP
1 mole of an ideal gas occupies 22.4 L(dm³) of volume.
which means that number of molecules occupy 22.4 L of volume.
So
4.8 dm³x 1 mole/22.4 dm³ = 0.214 moles Neon
0.214 moles x 6.02x10²³ atoms/mole = 1.29x10²³ atoms of Neon
No of Atoms in 4.8dm3 neon gas =1.29x10²³ atoms of Neon
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Final answer:
To find the number of atoms in 4.8 dm³ of neon gas at rtp, we calculate the moles of neon and then multiply by Avogadro's number, resulting in approximately 1.29 x 10²³ atoms.
Explanation:
To calculate the number of atoms in 4.8 dm3 of neon gas at room temperature and pressure (rtp), we can use Avogadro's law which states that one mole of an ideal gas occupies 22.4 liters (or dm³) at rtp. Thus, to find the number of moles of neon gas, we divide the volume of the gas by the molar volume at rtp (22.4 dm3/mol).
Number of moles (n) = volume / molar volume = 4.8 dm3 / 22.4 dm³/mol = 0.214 moles
To find the number of atoms, we multiply the number of moles by Avogadro's number (6.022 x 10²³ atoms/mol).
Number of atoms = number of moles x Avogadro's number = 0.214 moles x 6.022 x 10²³atoms/mol = 1.29 x 10²³atoms
Therefore, there are approximately 1.29 x 10²³ neon atoms in 4.8 dm³ of neon gas at rtp.
Ten gallons of water is a measurement of its mass. True False
Answer:
True
Explanation:
Its used to measure mass. Ten gallons weigh 8 pounds.
:D
Have a good day flopper :D
*eliza*
Answer:
false
Explanation:
weight and mass are very different your weight can change but your mass cannot so if you add 10 there isnt a difference in the mass
-, How many food Calories (Kcal) are in 3500 joules
Answer:
3500 Calorie
Explanation:
How many moles of calcium atoms do you have if you have 3.00 × 10²¹ atoms of calcium. (The mass of one mole of calcium is 40.08 g.)
Answer:
4.98x10^-3 mole
Explanation:
According to Avogadro's hypothesis, 1 mole of any substance contains 6.02x10^23 atoms. This greatly implies that 1 mole of calcium will also contain 6.02x10^23 atoms.
Now, if 1 mole of calcium contains 6.02x10^23 atoms,
then Xmol of calcium will contain 3x10^21 atoms i.e
Xmol of calcium = 3x10^21/6.02x10^23
Xmol of calcium = 4.98x10^-3mol
Therefore, 4.98x10^-3 mole of calcium contains 3x10^21 atoms
3.00 × 10²¹ atoms of calcium are equivalent to 4.98 × 10⁻³ moles of calcium atoms.
To convert atoms to moles we need a conversion factor: Avogadro's number. According to Avogadro's number: there are 6.02 × 10²³ calcium atoms in 1 mole of calcium atoms. The number of moles corresponding to 3.00 × 10²¹ atoms of calcium are:
[tex]3.00 \times 10^{21} atoms \times \frac{1 mol}{6.02 \times 10^{23} atoms} = 4.98 \times 10^{-3} mol[/tex]
3.00 × 10²¹ atoms of calcium are equivalent to 4.98 × 10⁻³ moles of calcium atoms.
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