What must happen before a chemical reaction can begin?
a. The activation energy must be exceeded.
b. The activation energy must be reached.
c. The concentrations of products and reactants must be equal.
d. The concentration of reactant molecules must be reduced.

Answers

Answer 1

Answer:

Your answer would be B

Explanation:

In order to start a chemical reaction, energy is needed

Answer 2

Answer:

Option B

The activation energy must be reached.

Explanation:

According to the collision theory, the following criteria must be met in order for a chemical reaction to occur: Molecules must collide with sufficient energy, known as the activation energy, so that chemical bonds can break. Molecules must collide with the proper orientation.

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Related Questions

The outer planets are made mostly of gas which makes them

Answers

Answer:

The four outer planets are all gas giants made primarily of hydrogen and helium. They have thick gaseous outer layers and liquid interiors. The outer planets have numerous moons, as well as planetary rings.

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Which of the following is an example of the endocrine system maintaining homeostasis?

1. Detecting a pain stimulus and sending a signal to the spinal cord to perform an automatic response
2. Discharging an excessive amount of hormones in the blood and not sending a signal to stop production
3. Sending a message to the pituitary gland to start producing a hormone when the levels in the body are too low
4. Using sense organs to get information about the outside world and direct an appropriate body response release

Answers

Answer:

The correct answer is "C".

Homeostasis is the maintaining of stable internal conditions in the body of a living being, such as body temperature or heart rate.

The endocrine system is an organ in the body which is in charge of secreting hormones that regulate numerous functions in the body, including metabolism, growth, sexual function, sleep, and mood among others. It is an essential organ which contributes to the state of homeostasis in the body.

Explanation:

Answer:

The answer is C

Explanation:

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The transcription of genes in E. coli that lack a termination sequence require _______ factor to terminate transcription.

Answers

Answer:

rho

Explanation:

The Rho factor is a prokaryotic helicase protein that acts in bacteria to mediate the process of termination of transcription. In Escherichia coli, the Rho factor is a hexameric ring-shaped helicase and each subunit of this factor contains two domains involved in RNA binding and ATP hydrolysis. The Rho factor binds to the transcription terminator site on single-stranded RNA and then continues along the messenger RNA (mRNA) strand until it reaches the RNA polymerase, subsequently triggering its dissociation from the DNA and thus the termination of transcription.

A friend who is not taking your Biology course fills a cup with ice and then a drink. The friend asks you why the ice in the cup is floating, and you are able to say that Group of answer choices water vapor is less dense than liquid water. ice is denser than liquid water. convection currents caused by temperature differences push upwards on the ice. the molecules are closer together in ice than in liquid water. the molecules are farther apart in ice than in liquid water.

Answers

Answer:

the molecules are farther apart in ice than in liquid water.

Explanation:

The correct answer would be that the molecules of water are farther apart in ice than in liquid water.

Water molecules in ice form are usually less dense than water molecules in liquid form. The water molecules in ice usually arrange themselves in a lattice form, unlike the random form in liquid water. This arrangement makes water molecules in ice to be more evenly spread out than in their liquid counterpart. Thus, ice is usually less dense than liquid water and will obey the principle of flotation by floating on water.

The ice in the cup is floating is due to: the molecules of water are farther apart in ice than in liquid water.

The density of a substance is the mass of the substance per unit of its volume. The formula to calculate the density is :

[tex]D = \frac{m}{v}[/tex], where D = density, m = mass of the substance, and v = volume

The density is the factor that determines if a substance will float or sink. The less-dense substance floats whereas, the more-dense object sinks.When water freezes to form ice then water molecules show expansion to create an open cage-like structure.This cage-like structure decreases the density of ice than the water so mass ice will have more volume as compared to liquid water.

Thus, the ice floats on water - the molecules of water are farther apart in ice than in liquid water.

Learn more about the density:

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Cell replication is important for reproduction of body cells and reproduction of gametes. Which type of reproduction occurs only in gametes

Answers

Answer:

meiosis

Explanation:

meiosis occurs in reproductive organs

the basic structural and functional unit of the living organism is​

Answers

Answer:

cell

Explanation:

The cell is the fundamental unit of structure and function in living things. All organisms are made up of one or more cells. Cells arise from other cells through cellular division.

Which is a property of every homogeneous mixture? Each part of the mixture has the same appearance. The mixture is made up of a solid dissolved in a liquid. The characteristics of the mixture change within a single sample. The components of the mixture change within a single sample.

Answers

Answer:

Each part of the mixture has the same appearance.

Explanation:

Homogeneous mixture consists of substances that mix evenly. Therefore has same appearance.

A population of birds lives on a small island. Another population of the same species lives on the mainland. The
distance between the island and the mainland is too great for birds to fly back and forth. Recently, a series of
sandbars and tiny islands have formed between the island and the mainland.

Answers

Answer:

The birds can now reach the Island.

Explanation:

The birds can now reach the Island because there is a sandbars and tiny Islands where they can rest for sometime as well as feed on the insects present at that sandbars and tiny Islands. Before these sandbars and tiny islands, the birds can't reach to the mainland due to large distance between Island and mainland so they have no capability to fly such large distance until the tiny Island and sandbars are appeared in the ocean.

Answer: an increase in gene flow between the bird populations

Explanation: :)

Select all that apply.
Which of the following are correctly spelled plural forms?
mongoosen
u mongooses
bluffs
bluffes
knifes
knives

Answers

Correctly spelled plural forms are mongooses, bluffs and knives.

Answer:

Mongooses Bluffs and Knives

Tom is having difficulty dorsiflexing and inverting his right foot. Which muscle is most likely involved in this problem

Answers

Answer:

It should be the tibialis anterior

Explanation:

I hope this helps!

True or false? Phototropism only happens after plants move from darkness into the light.
Group of answer choices

False

True

Answers

Answer:

phototropism only happens after plants move from darkness into the light (false)

Answer:

The answer is false.

Explanation:

write in short about medical occupation​

Answers

A vocation characterized by a specialized body of knowledge of medicine that its members must teach and expand, by a code of ethics and a duty of service that put patient care above self-interest, and by the privilege of self-regulation granted by society.Occupational medicine (also known as “occupational health”) is focused on the treatment of work-related injuries and illnesses. Physicians trained in occupational medicine diagnose and treat work-related injuries much more effectively than most primary care physicians.

How do you measure the area of the peepal leaf?Explain​

Answers

Answer:

Lay the leaves to be measured on a 1-cm grid and trace their outlines. Count the number of square centimeters. Estimate the area of the partial squares. ... Do not include the area of the stem (petiole) in your calculations.

Lay the leaves to be measured on a 1-cm grid and trace their outlines. Count the number of square centimeters. Estimate the area of the partial squares. ... Do not include the area of the stem (petiole) in your calculations.

6CO2 + 6H2O → C6H12O6 +602
In this chemical reaction H2O is a...
A. reactant.
B. product,
C. photosynthesis.

Answers

Answer:

water is a reactant because it reacts with carbon dioxide to form the products above

Flat bones have surfaces composed of ______ bone with internally placed ______ bone. Multiple choice question. compact, spongy

Answers

Answer: compact, spongy

Explanation:

Flat bones have surfaces composed of (compact) bone with internally placed (spongy) bone.

Flat bones are typically thin, although they're often curved. Some examples of flat bones are the cranial in the skull, scapulae which is known as the shoulder blades, ribs, and sternum. They're an attachment for muscles and are used in the protection of internal organs.

Match the type of ELISA with what it is used to detect. Question 2 options: detects presences and concentration of antigen/protein detects presences and concentration of antibody 1. indirect ELISA 2. sandwich ELISA

Answers

Answer:

ELISA is a technique of enzyme linked immunosorbent assay.

Explanation:

The full form of Elisa is enzyme linked immunosorbent assay. The ELISA technique is a boichemical technique that is used to measure the amount of protein or the antibody in a solution and is divided into three types :

Competitive ELISADirect ELISA or Sandwich ELISAIndirect ELISA

1. Indirect ELISA ---  detects the presences and concentration of the antibody.

2. Sandwich Elisa or Direct ELISA  ---  detects the presences and concentration of the antigen/protein.

Which is found in both DNA and RNA?
A. thymine
B. uracil
C. adenine
D. ribose

Answers

Answer:

in DNA it is deoxyribose and in RNA it is ribose

Answer:

C. Adenine

Explanation:

DNA and RNA both have adenine, guanine, and cytosine.

DNA has thymine, which RNA does NOT have.

RNA has uracil, which DNA does NOT have.

Which method of waste treatment is LEAST harmful to the environment?​

Answers

Answer:

c

Explanation:

because burning burying and landfill are all harmful

which anwser choice best describes a community

Answers

Answer:

Community Definition. A biotic community, also known as a biota or ’biocoenosis’, is the group of organisms that live...

Types of Community. There are two main types of community. A major community is the smallest ecological unit which is...

Characteristics of a Community. The features within communities are highly variable, and there are a number of

Explanation:

After nervous stimulation stops, calcium ions returning to the sarcoplasmic reticulum prevent ACh in the synaptic cleft from continuing to stimulate contraction True False

Answers

Answer:

False.

Explanation:  

Neurotransmitter release occurs from the nervous terminal or varicosities in the neuronal axon. When an action potential reaches the nervous terminal, the neurotransmitter is released by exocytose. The molecule binds to its receptor in the postsynaptic neuron, triggering an answer. As long as the signal molecule is in the synaptic space, it keeps linking to its receptor and causing a postsynaptic response. To stop this process the neurotransmitter must be taken out from the synaptic space. There are two mechanisms by which the neurotransmitter can be eliminated:

Enzymatic degradation/deactivation: There are specific enzymes in the synaptic space, which are in charge of inactivating the neurotransmitter by breaking or degrading it. The enzyme acetylcholinesterase prevents ACh from continuing to stimulate contraction.

Reuptake: Receptors located in the presynaptic membrane can capture de molecule to store it back in new vesicles for posterior use. These transporters are active transport proteins that easily recognize the neurotransmitter.  

According to the body-cover theory of phonation, which part of the vocal fold is not considered to be a portion of the cover

Answers

Answer: B. Thyroarytenoid muscle

Explanation:

The options include:

A. Epithelium

B. Thyroarytenoid muscle

C. Superficial layer of the lamina propria

D. Intermediate layer of the lamina propria

The cover-body theory of vocal fold vibration was published by Hurano in 1974 and he described the morphological structure of the vocal folds. He also divided them into the body and cover layer biomechanically.

The main substance of the vocal fold is regarded as the thyroarytenoid muscle. The muscle provides most of the mass of the vocal cord.

the most common mineral group is broken into the subgroups of ferromagnesium and non ferromagnesium

Answers

Answer: The answer would be Silicate

Explanation: They are made out of silicon and oxygen

Which of these is an example of an adaptive (or specific) immune response?

A.
A person's immune system responds to an insect bite by increasing blood flow to the area and causing it to become inflamed.

B.
A person's immune system recognizes that a bacterial infection is present and signals the hypothalamus to increase body temperature.

C.
A person's immune system recognizes viral particles due to a previous vaccine and creates antibodies to fight off the resulting infection.

D.
A person's immune system responds to dirt entering the eye by increasing tear flow and flushing the dirt out of the eye.

Answers

Answer:

I'm not quite sure but I believe the answer is C.

Explanation:

7. Give two examples of biochemical reactions and explain how an organism uses ATP within the reactions.



Answers

Answer:

Because of its energy supply, ATP is necessary for all biological reactions.

ATP is employed both in salt and potassium pumping operations and in the cellular breathing mechanism.

Explanation:

The breakdown of glucose, which frees the cell's energy for life functions, is an example of a catabolic response. Endothermic reactions are called anabolic processes in organisms. The connection between amino acids and a protein is an example of an anabolic response.

If a cell needs energy, this link breaks into adenosine diphosphate (ADP) and a free molecule of phosphate... With an excess power of the cell, this energy is stored by creating ATP from ADP and phosphate. For any muscular contraction, ATP is needed for metabolic reactions.

-To break down one glucose into pyruvate molecules in Glycolysis 2 ATP molecules 4 ATP molecules are produced for a net addition of 2 ATP molecules.

-An inorganic carbon is converted into sugar by ATP in photosynthesis.

Which base does Adenine pair with in RNA?
A. Uracil
B. Guanine
C. Thymine
D. Cytosine

Answers

Answer:

A. Uracil would be the answer.

What's different about the 4 dams

Answers

Answer:

dams could mean the bridges

dams could be mean like something real good

It could also dams as in girl eg-damsel in distress, dams was a old word used in the 70s for girls

atrial fibrillation, a dangerous form of irregular heartbeat is associated with the intake of _____.

Answers

Answer:

Palmitic acid

Explanation:

Intake of palmitic acid is associated with atrial fibrillation.

Palmitic acid - is a saturated long-chain fatty acid and a straight chain saturated fatty acid with a 16-carbon backbone. Palmitic acid is found naturally in palm oil and palm kernel oil, as well as in butter, cheese, milk and meat. It is a conjugate acid of a hexadecanoate.

Hexadecanoate - is a long-chain fatty acid anion that is the conjugate base of hexadecanoic acid (palmitic acid).

What is the approximate age of the ash footprints at Laetoli? (Hint: what is the radiometric age of Laetoli?)

Answers

Answer:

The correct answer is - 3.66 million years ago.

Explanation:

Laetoli, located on the Eyasi Plateau which is known for the remains or footprints of the oldest hominin that were formed and preserved by a series of events -  a volcanic eruption, a rainstorm, and another ashfall.

The remains and footprints were discovered at 1978 and are attributed to Australopithecus afarensis. The age of this remaining footprint can be estimated with the help of the radiometric method of the remains which tells that the footprints are 3.66 million years ago formed.

For a reaction, A H= 2 kJ. For which value of TA Sis the reaction spontaneous?

Answers

Answer:

option a is the answer I think so

Answer:

option a

Explanation:

For which value of TA Sis the reaction spontaneous?

what is cell wall ?

please help.​

Answers

Answer:

A cell wall is a structural layer found just outside the cell membrane that surrounds various types of cells. It may be robust, flexible, and even stiff at times. It functions as a filtration mechanism as well as providing structural support and protection to the cell.

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