Which is a redox reaction?A) 2KBr + F2 ---> 2KF + Br2
B) 2HCL + Mg(OH)2 --> 2HOH + MgCl2
C) 2NaCl + H2SO4 --> Na2SO4 + 2HCl
D) Ca(OH)2 + Pb(NO3)2 --> Ca(NO3)2 + Pb(OH)2

I know the answer is A, but confused as to why that is. Can someone explain this for me? Thanks.

Answers

Answer 1

Answer: You have to look at the oxidation states of each atom in the reaction. Since redox reactions involve the transfer of electrons from one element to another, 2 elements need to have oxidation state changes.
option a is the only option that has a change in oxidation sates. Fluorine goes from 0 to -1 indicating that it gained electrons (got reduced) while bromine goes from -1 to 0 indicating it loses electrons (got oxidized).
(2Br⁻→Br₂+2e⁻ and F₂+2e⁻→2F⁻).

I hope this helps. Let me know if anything is unclear.

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H e l p,,, ill give brainliest :)
Which statement most accurately describes the behavior of a catalyst? (A) A catalyst increases the ∆G of a reaction and hence the forward rate. (B) A catalyst reduces the ∆H of a reaction and hence the temperature needed to produce products. (C) A catalyst reduces the activation energy for a reaction and increases the rate of a reaction. (D) A catalyst increases the equilibrium constant and final product concentrations

Ayala is making salad dressing. She mixes oil and vinegar in a blender until a smooth consistency is formed. Explain whether this is a heterogeneous or a homogeneous mixture and why.

Answers

Answer: The mixture formed will be heterogeneous mixture.

Explanation: When we mix oil and vinegar and blend it together to form a smooth mixture, the final mixture will still be heterogeneous in nature.

As we know that vinegar is a solution of acetic acid in water, which is polar in nature and oil is non-polar in nature.

When, we mix polar compound with a non-polar one, the resulting mixture may mix for a certain time, but after a time, we will be able to see the two layers in a mixture.

And heterogeneous mixtures are defined as the mixtures in which there is a distinct physical boundary present between the solutions in a mixture.

Hence, the mixture of oil and vinegar is a heterogeneous mixture.

Sample Response: A homogeneous mixture can only form when one of the substances can dissolve the other one. Oil and water cannot dissolve each other, so they must form a heterogeneous mixture with small particles of vinegar dispersed throughout the oil, yet not dissolved.

Explanation: Hope this Helps!

Which of the following uses the relationship between the DNA of various groups of organisms to determine how long ago they diverged evolutionarily from one another? Carbon dating
Fossils
Timelines
Molecular clocks

Answers

Molecular clocks use the relationship between the DNA of several groups of organisms to evaluate how long ago they diverged evolutionarily from one another. Therefore, option (4) is correct.

What are Molecular clocks?

The molecular clock can be described as a figurative term for a technique that utilizes the mutation rate of biomolecules to determine the time when two or more life forms diverged. The biomolecular data used are usually nucleotide sequences for DNA, RNA, or amino acid sequences for proteins.

The benchmarks for calculating the mutation rate are often fossil or archaeological dates. The molecular clock is commonly used in molecular evolution to estimate times of speciation or radiation.

The molecular clock can only give one time period as it cannot assign concrete dates. For viral phylogenetics and ancient DNA studies, the areas of evolutionary biology, the intermediate samples can be utilized to more precisely calibrate the molecular clock.

Learn more about Molecular clocks, here:

brainly.com/question/286720

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Molecular clocks because the measure changes in DNA or proteins to indicate degrees of relationship among species.Molecular clocks, together with evidence from the fossil record, allows scientists to estimate how long ago various groups of organisms diverged evolutionarily from one another

What Kelvin temperature is equal to -33DC? A) 306K B) -33K C) 240K D) 33K

Answers

Final Answer:

$\boxed{\boxed{\huge\textsf{$\rm -33^(\,\circ)C=240.15\,K$}}}$

Kelvin Absolute Temperature:

The kelvin, symbol K, is a unit of measurement for temperature. The Kelvin scale is an absolute scale, which is defined such that 0 K is absolute zero, the lowest temperature possible on Earth.

Historically developed from the Celsius scale, the conversion is thus:

$\boxed{\Large\textsf{$\rm 0^(\,\circ)C=273.15\,K$}}$

And absolute zero, 0 K = -273.15° C, the lowest temperature possible.

Knowing this, we can solve the question as:

$\Large\textsf{$\rm -33^(\,\circ)C=(-33+273.15)\,K$}\n\n\boxed{\boxed{\Large\textsf{$\therefore\rm -33^(\,\circ)C=240.15\,K$}}}$

$\hrulefill$

To learn more about the Kelvin Absolute Temperature Scale:

brainly.com/question/24652526

1 ℃ = 273.15 K.

The Kelvin temperature equal to -33℃ is 240 K.

Which of these is NOT a way, or a proposed way, to store nuclear fuel rods after they have been used in a nuclear reactor?

Answers

The question given above is not complete, the options attached to the question is given below:

A). Putting them in a deep pool of water

B). Burying them in a deep underground storage facility

C). Sending them on the shuttle to be suspended in space

D). Putting them in concrete/lead casks and sitting at thereactor site

ANSWER

The correct option is C.

There are many ways of storing spent nuclear fuel rods, these include: immersing them in deep pool of water, storing them in lead casks and burying them in deep underground storage. These forms of storage are utilized in order to protect people and the environment from the harmful radiations that radiate from these fuel rods. Spent fuel rods must never be exposed, therefore it is not possible to suspend them in space.

Answer:

Explanation:

Suppose that a certain fortunate person has a net worth of $79.0 billion ($7.90×1010). If her stock has a good year and gains $3.20 billion (3.20×109) in value, what is her new net worth?

Answers

A net worth: $79.0 billion.
Value of stock : $3.20 billion.
New net worth:
$79.0 + $3.20 = $82.20 billion = $82.20 * 10^9 = $8.20 * 10^10

Answer:

$8.20 * 10^10

Explanation:

Which material is a pure substance?A) alloy

B) compound

C) mixture

D) solution

Answers

The answer is B. The material that can be considered as a pure substance is the compound. A pure substance is defined as a material that is only composed of one substance. The other choices given are mixtures where there are two or more different substances in a material.

B) compound is a pure substance

Further explanation

A pure substance can be an element or compound.

The element is a single substance that cannot be broken down anymore or the simplest substance.

While the compound is a pure substance that is formed from a combination of two or more elements through chemical reactions and has a constant chemical ratio.

A mixture is a combination of two or more single substances. The properties of the mixture component are not lost / unchanged as in compounds.

The mixture can be divided into a homogeneous mixture if the composition / ratio of each substance in the mixture is the same and heterogeneous mixture if the ratio of the composition of the substances is not the same (can be varied) in each place.

Mixtures can also be divided into solutions, suspensions and colloids based mainly on the size of the particles

A) alloy

alloy is a mixture of elements that have metal properties

B) compound

Compounds are represented in chemical formulas which can be separated into their constituent elements by chemical processes

C) mixture

can be separated by physical or mechanical means, the composition can be changed depending on the proportion of pure substances that form it

D) solution

Solution is: a mixture of two or more substances consisting of a solute and a solvent. The particle size of the solution is very small, less than 1 nm.