Answer:
Average atomic mass = 79.9 amu.
Explanation:
Given data:
Average atomic mass of Bromine = ?
Atomic mass of 1st isotope = 78.92 amu
Relative abundance of 1st isotope = 50.69%
Atomic mass of 2nd isotope = 80.92 amu
Relative abundance of 1st isotope = 49.31%
Solution:
Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) / 100
Average atomic mass = (50.69×78.92)+(80.92×49.31) /100
Average atomic mass = 4000.45 + 3990.16 / 100
Average atomic mass = 7990.61 / 100
Average atomic mass = 79.9 amu.
6. All changes in states of matter (freezing, evaporation, condensation, etc.) are
a. physical changes
b. chemical changes
Pretty sure its Physical Changes
No chemical reaction is happening.
Answer:
Changes of states are physical changes
Explanation:
They are reversible changes that do not involve changes in matter's chemical makeup or chemical properties.
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A chemist is identifying the elements present in a sample of seawater. What characteristic of an element’s atoms always determines the element’s identity?
answer please!!!!!!!!!!!!!!!!!!!!!!!!✌✌✌
Answer:
hxtististsy z7tzotz8tsx lhsitzrizrs ypzyztozkt udriztkzto
5)
Experiments with gold foil indicated that atoms
A)
usually have a uniform distribution of positive charges
B)
usually have a uniform distribution of negative charges
C)
contain a positively charged, dense center
D)
contain a negatively charged, dense center
Answer:
c
Explanation:
I just learned all this in chemistry too lol
got 100 on the test last week so its good
Experiments with gold foil indicated that atoms contain a positively charged, dense center and the correct option is option C.
Experiments with gold foil, known as the Rutherford gold foil experiment, were conducted by Ernest Rutherford in 1911. In this experiment, he bombarded a thin gold foil with alpha particles.
Most of the alpha particles passed through the foil with little deflection, but some of them were deflected at large angles, and a small fraction even bounced back. This observation led Rutherford to conclude that the atom contains a positively charged, dense center called the nucleus, where most of its mass is concentrated. He proposed the nuclear model of the atom, which became a significant advancement in the understanding of atomic structure.
Thus, the ideal selection is option C.
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Deforestation would most directly result in which of the following?
A. The disappearance of native species.
B. Industrialization of an area.
C. The depletion of the ozone layer.
D. Global warming.
Explain the saying, “Rome was not built in a day
Answer:
What is the Rome was not built in one day with speech
A student wants to develop a model of an organism's cell that lacks chloroplasts. Which statement BEST explains how the lack of chloroplasts affects an organism?Your answer:An organism that lacks chloroplasts would not be able to convert sunlight into chemical energy through photosynthesis.An organism's cells would not be able to reproduce since the chloroplasts contain the genetic material.An organism that lacks chloroplasts would not be able to manufacture all the protein required by its cells
Recall that the main function of chloroplasts is to convert sunlight to chemical energy, or to carry out photosynthesis. Plant (and eukaryotic algae) cells contain these organelles, while animal cells do not, and hence, animals cannot carry out photosynthesis.
So, a lack of chloroplasts would mean that an organism would not be able to convert sunlight into chemical energy through photosynthesis.
Plants cells, and specifically the chloroplast organelle, are able to absorb sunlight, and together with CO₂ and water, produce glucose (for the plant to eat) and oxygen (which is released into the atmosphere). That glucose is further broken down by the plants' mitochondria. Animals directly consume the glucose to be broken down and converted into energy, hence why we do not have - nor need - chloroplasts in our cells.
the further a star is away from Earth, the more it is
Answer: the more big it is
Explanation:
Answer:
The more it is red shifted.
Hope this helped, have a good day
A state property X has a value 89.6 units. It undergoes the following changes, first increase by
3.6 units, then increase by another 18.7 units, then decrease by 12.2 units and finally attains a
value of 85.5 units The value for this series of change is A) 14.2 units
B) -4.1 units C) 108.3 units
D) uncertain
Answer:
B) -4.1 units
Explanation:
According to this question, a state property X has a value 89.6 units. It undergoes the certain changes as follows:
- first increase by 3.6 units
- then increase by another 18.7 units
- then decrease by 12.2 units
- and finally attains a value of 85.5 units
This can be mathematically represented by 89.6 - {3.6 + 18.7 - 12.2 - x) = 85.5
To get x, we say;
89.6 + 3.6 = 93.2
93.2 + 18.7 = 111.9
111.9 - 12.2 = 99.7
99.7 - 85.5 = 14.2units.
The changes that occured is represented as follows:
= (3.6 + 18.7) - (12.2 + 14.2)
= 22.3 - 26.4
= -4.1 units
what occurs at the cathode of a galvanic cell? (sorry about the picture my back camera is broken)
Answer:
The reduction half-reaction of a redox reaction
Explanation:
(just took the test)
The reduction of half-reaction of a redox reaction. Hence, option B is correct.
What is an electrolytic cell?An electrolytic cell converts electrical energy into chemical energy or vice versa.
A galvanic cell is an electrochemical cell in which chemical energy is converted to electrical energy. The chemical reaction which drives a galvanic cell is a redox reaction i.e. a reduction-oxidation process.
A typical galvanic cell is composed of two electrodes immersed in a suitable electrolyte and connected via a salt bridge. One of the electrodes serves as a cathode where reduction or gain of electrons takes place. The other half cell functions as an anode where oxidation or loss of electrons occurs. Batteries and fuel cells are examples of galvanic cells.
Hence, option B is correct.
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What is the K-T boundary?
Answer:
Definition
The Cretaceous/Tertiary boundary (KT), also often called the Cretaceous/Paleogene (K/Pg) boundary, marks the contact between the Mesozoic and Cenozoic eras ∼ 65 Ma ago. The KT boundary is characterized by the last major mass extinction in Earth history that saw the demise of the non-avian dinosaurs along with 50% to 60% of the Earth fauna and flora.
helpppppp i hate chemistry
I will give brainiest who helps me with the correct answer
I promise
5. Name the compound which contain Strontium, Fluorine, and Oxygen.
Options:
Strontium fluorate
Strontium fluoride
Strontium chlorate
Strontium fluorine
Answer:
The first option: Strontium Fluorate.
Explanation:
because Fluorine and oxygen combines to make fluorate, Strontium stays the same.
p.s: i need help in geo and there's an exam tomorrow.
Please Help!!!
Which of the following is not a good indication that a chemical change has occurred?
A. The formation of gases
B. A change in color
C. A scratched surface
D. The release heat or light
Answer:
C.
Explanation:
what is a factor of matter
Explanation:
The factor of matter are solubility, boiling point, melting point, temperature, density and reactivity
If the atomic number of Lithium is 3 and its mass number is 7, how many protons, electrons, and neutrons does a neutral
atom of Li have
Answer:
Protons = 3
Neutrons = 4
Electrons = 3
Explanation:
For every atom, the atomic number is equal to the number of protons.
In a neutral atom (atom with no charge) the number of protons is equal to the number of electrons.
To calculate neutrons subtract the number of protons (atomic number) from the rounded molar mass:
7 - 3 = 4 neutrons
write the atomic number of the following: a) phosphorus b) silicon c) chlorine d) argon
Answer:
a,15b,14c,17d,18I hope it helps youAnswer:
a) 15
b) 14
c) 17
d) 18
Explanation:
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how do i caculate velocity
Answer:
Velocity Equation in these calculations:
Final velocity (v) of an object equals initial velocity (u) of that object plus acceleration (a) of the object times the elapsed time (t) from u to v.
Explanation:
What type of stress occurs when a rock mass is pushed in opposite directions?
Answer:
Shear stress
Explanation:
Answer:
C-Shearing
Explanation:
Shearing is a type of stress caused when a rock mass is pushed in opposite directions Rocks break and split apart and change shapes. Shearing is common at transform boundaries
What is the product of the synthesis reaction between calcium and iodine?
Answer:
The product of the synthesis reaction is CaI.
Explanation:
In chemistry, chemical equations are the representation of chemical reactions between elements, compounds, substances, or molecules.
They are written using element symbols (and sometimes including their current state of matter).
Therefore, if we wanted to show the reaction of sodium and chlorine to make sodium chloride, or table salt, we would illustrate it as such:
[tex]\bullet \ \text{Na + Cl} \rightarrow \text{NaCl}[/tex]
A synthesis reaction in chemistry is the combination of two or more elements, compounds, molecules, or substances to make one compound, molecule, or substance.
The parent equation for a synthesis reaction is:
[tex]\bullet \ \text{A + B}\rightarrow \text{AB}[/tex]
Therefore, we need to find out what the element symbols are for both calcium and iodine.
If we reference a periodic table, we will see that calcium is atomic number 20 and has the symbol Ca.
Additionally, when we locate iodine, we will see that it is atomic number 53 and has the atomic symbol I.
Now, we just need to create the reaction equation.
[tex]\text{Ca + I}\rightarrow \text{?}[/tex]
We know that we are dealing with a synthesis reaction, or a combination, so the elements will combine to make one substance.
With this information, we can make an equation:
[tex]\text{Ca + I} \rightarrow \text{CaI}[/tex]
Therefore, the product of the synthesis reaction is CaI.
Note: Please note that "I" is an uppercase i.
State the career function of mechanical engineering
Answer:
Mechanical engineers design power producing machines, like electric generators, internal combustion engines, and steam and gas turbines, also power using machines, such as refrigeration and air-conditioning systems. Mechanical engineers design other machines inside buildings, such as elevators and escalators.
Explanation:
Which of the following equations is not balanced?
Explanation:
i think the answer is first and last
Determine the final temperature of a system, if 120 grams had an initial temperature of 80°C and mixes with 3,000 g of water at an initial temperature of 20°C
Answer:
The final temperature of the mixture is 22.3°C
Explanation:
Assuming that the 120 g substance at 80°C is water, final temperature of the mixture can be determined using the formula:
Heat lost = Heat gained
Heat = mc∆T where m is mass, c is specific heat capacity of water, and ∆T is the temperature change = Tfinal - Tinitial.
Let the final temperature be T
Heat lost = 120 × c × (T - 80)
Heat gained = 3000 × c × ( T - 20)
Equating the heat lost and heat gained
120 × c × -(T - 80) = 3000 × c × (T - 20)
9600 - 120T = 3000T - 60000
60000 + 9600 = 3000T + 120T
69600 = 3120T
T = 69600/3120
T = 22.3°C
Therefore, the final temperature of the mixture is 22.3°C
What evidence always shows that a chemical change has happened?
O A. The total mass of material changes.
O B. A new substance is produced.
C. A solid material dissolves in a liquid.
O D. A liquid changes into a solid.
Answer:
B. A new substance is produced.
Explanation:
In chemical changes, you will always have a new end product from the reactants that were used within the process.
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Which element is not conserved in this unbalanced chemical equation?
2NaOH + H2S04 - NaSO4 + 2H20
Ο Α. Η
O B. S
O c. O
O D. Na
In the given unbalanced reaction, the number of sodium is not balanced. There must have two sodium in the product side also. The correct formula of sodium sulphate is Na₂SO₄.
What is mass conservation law?According to the law of conservation of mass, the total mass of a system is conserved. Thus, mass can neither be created nor be destroyed. Therefore, for a chemical reaction, the total mass in the product side must be equal to the total mass in the reactant side.
The balanced equation of a chemical reaction thus, obeying the mass conservation law where, each element have to be equal in number in both sides.
In the given reaction, the number of Na in reactant side is 2 and that in product side is 1 only. Thus total mass of sodium is not conserved. It can be corrected as Na₂SO₄ in the product side.
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A student has a remote control for a television. The student points the
remote at the television and presses a button on the remote labeled
Volume. A small red light flashes on the front of the remote. The student
observes that the sound from the television becomes lower.
Which statement best describes how the remote control communicates
with the television to change the volume of the sound?
a
Oь
Od
The remote control sends microwaves toward the television that are absorbed by the front of the television
The remote control sends low-energy infrared radiation to a light detector on the front of the television
The remote control sends radio waves in many directions, which bounce off the walls of the room toward the front of the
television
The remote control sends sound waves in many directions, which bounce off the walls of the room toward a vibration detector on
the front of the television
od
Answer:
The remote control sends low-energy infrared radiation to a light detector on the front of the television
Explanation:
The signal between a remote control and the TV controls consists of pulses of infrared light, which is invisible to the human eye
What is the mass of 0.9210 moles of sulfur dioxide gas (SO2)?
Answer:
58.944 g
Explanation:
From the question given above, the following data were:
Mole of SO2 = 0.9210 mole
Mass of SO2 =?
Next, we shall determine the molar mass of SO2. This can be obtained by adding the molar mass of sulphur and oxygen together as illustrated below:
Molar mass of SO2 = 32 + (2 × 16)
= 32 + 32 = 64 g/mol
Finally, we shall determine the mass of 0.9210 mole of SO2 as follow:
Mole of SO2 = 0.9210 mole
Molar mass of SO2 = 64 g/mol
Mass of SO2 =?
Mole = mass /Molar mass
0.9210 = mass of SO2 / 64
Cross multiply
Mass of SO2 = 0.9210 × 64
Mass of SO2 = 58.944 g
Thus, the mass of SO2 is 58.944 g.
True or false. The greater the distance that the plane moves from an object, the lower the force that will be applied when the action is taken.
Answer:
I think its false-
Explanation:
Answer:
I think it is true i am not sure
What is the best definition of biology?
A. The study of energy and light
B. The study of matter
C. The study of applied science
D. The study of living things
Answer:
D. The study of living things
Explanation:
prefix "bio-" means life, living things
The scientist philosopher Aristotle is known as the father of biology. The best definition of biology is the study of living things. The correct option is D.
What is biology?The branch of science which deals with the study of living organisms, their origins, anatomy, morphology, and distribution is known as the biology. Biology is a natural science discipline which studies living things.
The study of living things and their important processes is explained in biology. This field deals with all the physiochemical aspects of life. It is sub divided into other branches like botany, physiology and zoology.
Thus the correct option is D.
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Florida is known for long, very warm summers with high humidity. Which of the following is a description of the weather in Florida?
A. Daily thunderstorms are very common in Florida.
B. South Florida has a tropical savanna ecosystem.
C. Florida has a brief annual summer rainfall season.
D. North Florida is known for its humidity.
Answer:
A
Explanation:
The description of the weather in Florida is daily thunderstorms are very common in Florida.
What are thunderstorms?Thunderstorms are lightning storms or electrical storms.
Thunderstorms are caused by unstable warm and cold air.
Lightning, hail and heavy rains happen in thunderstorms.
It causes high damage to houses and properties.
Thus, the correct option is A.
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Why are flowers brightly colored?
Answer: In order to help the plants reproduce, flowers that are bright in color are meant to attract birds, bees and other insects. In the genetics of a flower, bright or dull colors are set in
Explanation: