Answer:
In the Fertile Crescent in the Middle East, cereal crops were first domesticated about 11,000 years ago. Generally, the first domesticated crops were annuals with big seeds or fruits. ... Humans began to transition from a hunter-gatherer culture to a settled farming society as domestication took place.
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3.
What are valence electrons? How do you quickly determine the number of valence electrons an
atom has?
Answer:
Electrons that arent electrons
Explanation:
I teach chem
Answer:
Valence electrons are the electrons found in the highest and main energy level of the atom, being these responsible for the interaction between atoms of different species or between atoms of the same species. You can quickly determine these by looking at a periodic table like this one... Which is where the roman numbers come in and show the valence electrons. (THIS TABLE IS IN SPANISH, I hope you still recognize the symbols.) :))
In a certain chemical reaction, the bond energy of the products is 67 kJ and
that of the reactants is 52 kJ. Because energy is conserved, how much
potential energy does the system release or absorb?
O A. The reaction uses up 15 kJ of energy from the reaction system.
B. The reaction creates 15 kJ of energy when bonds form.
C. The reaction system absorbs 15 kJ of energy from the
surroundings.
O D. The surroundings absorb 15 kJ of potential energy.
D. The surroundings absorb 15 kJ of potential energy.
Further explanationChemical bonds = potential energy
ΔH reaction from bond energy is a breaking and forming reaction of the 2 reacting molecules
Can be formulated:
ΔH rxn = ∑ the energy of the reagent bonds broken - ∑ the energy of the bonds formed by the product
The bond energy of the products is 67 kJ and reactants 52 kJ
[tex]\tt \Delta H_{rxn}=52-67=-15~kJ[/tex]
ΔH = negative ⇒The reaction is exothermic(releases heat to surrounding)
Answer:
C is right
Explanation:
In chemical reactions, what does the law of conservation of mass mean?
Group of answer choices
Matter is not created nor destroyed.
The total mass of the products is greater than the total mass of the reactants.
The total mass of the reactants is less that the total mass of the products.
Matter is not changed.
Answer
The law of conservation of mass states that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations. According to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants.
An element is lustrous, brittle, and silver colored. What type of element is it
Metal
Metalloid
Non Metal
Other
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In Natural selection, individuals whose unique characteristics are well-suited for an environment tend to survive and produce more offspring. true or false? i need this help!right now!
Answer:
True
Explanation:
True. If an animal has attributes to it that help it survive better in an environment, it will survive better than its counterparts who do not have this attribute. More survival = More offspring
Answer:
True.
Explanation:
It's called survival of the fittest. Animals are genetically supposed to be well suited to their environment and if they aren't, they die out.
How many protons, neutrons, and electrons are in C -14
18. Which of these is an ion?
A. Fluorine with 9 protons
B. Calcium with 18 electrons
C. Calcium with 18 neutrons
D. Fluorine with 9 neutrons
solve this very easy choose option fast
Answer:
i think its alcohol and salt because they put salt on the ground to dissolve the snow so what I think is its alcohol and salt cuz they both look like they would evaporate pretty easy and alcohol evaporates really really easy so I think it's alcohol and salt because salt May absorb it or something I don't know but yeah
Answer: alcohol and iodide
Explanation:
Nervous tissue transmits messages throughout the human body by
contracting.
providing protection.
conducting impulses.
absorbing vital nutrients.
Answer: conducting impulses
Explanation:
just did it on edge
Answer:
c. conducting impulses.
Explanation:
got it right on edg, hope this helps!
Substances which will glow in the dark after being exposed to sunlight are:
radioactive
photosensitive
luminescent
phosphorescent
Answer:
If something glows in the dark it is phosphorescent.
PLEASE HELP ME!!
I am smaller than Rb and bigger than Na but we are in the same family.
H
K
N
Cs
Is it easier to remove an electron from Mg or from Cl?
Mg
Cl
Answer: K and Mg
Explanation:
The first one refers to the atomic radius and increases going down and to the left on the periodic table. K is in between Rb and Na.
is a dolerite a mineral or a rock
Answer:
rock is the correct answer
Explanation:
Answer: here's the thing: rocks are minerals.Well, made out of them. so you can say that dolerite is a rock, but it is made out of minerals
Explanation:
How are plants,animals,and bacteria alike
Answer:
They all carry bacteria you have to feed it
Explanation:
Answer:
They all have Organisms.
Explanation:
Hope this helps!
Brainliest Please.
What is convection?
Transfer of heat through objects touching source
Transfer of heat through direct physical contact
Transfer of heat through electromagnetic waves
Transfer of heat through the movement of particles
Answer:
D.
Explanation:
(3.1 x 10^3) (1.00 x 10^7) =
Answer:
(3.1 x 10^3) (1.00 x 10^7) = 31000000000
How many electrons are present in one neon
atom?
Answer: 10 electrons
That means there are 10 electrons in a neon atom. Looking at the picture, you can see there are two electrons in shell one and eight in shell two. Because shell two has eight electrons it is now full.
Explanation: Hopefully this helped!
FILL IN THE BLANKS ASAP 40 POINTS AND BRAINLIST
Answer:
1.) land
2.) water
3.) warmer
4.) rises
5.) sea
Explanation:
Hot air rises, and land heats up first.
Answer:
Here are the answers:
1.) land
2.) water
3.) warmer
4.) rises
5.) sea
Explanation:
During a day at the beach, the land heats up faster than the water. Because of this, the air over land rises over the land and the cooler, more dense air, blows into the ocean, creating a sea breeze.
Write a balanced equation for each of the acid-base reaction given below.a. Aqueous sulfuric acid with aqueous potassium hydroxide.
Answer:
H2SO4 + 2KOH => K2SO4 + 2H2O
Explanation:
The acid-base reaction is a type of chemical reaction that involves the exchange of hydrogen ions.
The acid-base reaction between aqueous sulfuric acid ( H2SO4 ) and aqueous potassium hydroxide (KOH) is a neutralization reaction that results in potassium sulfate and water.
sulfuric acid + potassium hydroxide => potassium sulfate + water
So, the balanced equation for this reaction is as follows:
H2SO4 + 2KOH => K2SO4 + 2H2O
Hence, the correct answer is "H2SO4 + 2KOH => K2SO4 + 2H2O".
what is heavier 1 pound of bricks or 1 pound of feathers
Answer:
They are both the same.
Explanation:
ONE POUND of feathers
ONE POUND of brick
Answer:
They are both the same
Explanation:
Even though feathers are lighter they are both 1 pound. Why do you have so many feathers?!?!?
A deck of cards has dimensions 8.9cm x 5.72cm x 1.82 cm. What is the volume of the deck in cubic centimeters?
The volume of the deck having dimensions 8.9cm x 5.72cm x 1.82 cm is 92.65 cubic centimeters.
How to find the volume of the Cube ?The volume of a cube is obtained by multiplying its side three times. The formula of volume of the cube can thus be given as, Volume of cube = s³, where s is the side length of the cube.
Given ;
Length : 8.9cmBreadth : 5.72cmHeight : 1.82 cmFormula used ;
Volume = Length x Breadth x Height
= 8.9cm x 5.72cm x 1.82 cm.
= 92.65 cm³ i.e, 92.65 cubic centimeters
Learn more about volume here ;
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A deck of cards has dimensions 8.9cm x 5.72cm x 1.82 cm. What is the volume of the deck in cubic centimeters?
Answer:
92.65256 cm^3
Explanation:
To find this, we can simply multiply all three dimensions to get the answer in cubic centimeters, and we get the answer above. If you want to be more specific, we can go by the sigfig rule and the answer would be rounded to 93 cm^3.
Subscripts are used in a chemical formula to show the number of atoms of each element.
True or False.
If endothermic means that the temperature increases and exothermic means it decreases, it 64 degrees to 64 degrees (it stayed the same) endothermic or exothermic?
Answer:
The answer is none of them.
Explanation:
I did the study guide...Also, if it has no change, it is neither.
Why do you think the hot red water sank to the bottom?
Answer:
i did this in school :) but Hot water will rise to the top because it is less dence and cold water will sink to the bottom because it is more dence
Explanation:
why some metals are more dense than others
Enter your answer in the provided box.
A sample of chlorine gas is confined in a 7.17-L container at 491 torr and 37.0°C.
How many moles of gas are in the sample?
mol Cl2
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How does energy (heat) flow in the ocean?
Answer:
There is a connection between the ocean and the atmosphere (they work together to move heat and fresh water across the globe) . Heat can be transferred between the surface of a sea or ocean and the atmosphere through ;
RadiationConvection,Turbulent heat exchange Evaporation of waterCondensation of water vapor above the sea or ocean .Explanation:
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Air masses that form over large bodies of water are moist. What process determines the amount of moisture in an air mass?
Answer:
I don't know if this is right but try it. The amount of water vapor in the air is called absolute humidity. The amount of water vapor in the air as compared with the amount of water that the air could hold is called relative humidity. This amount of space in air that can hold water changes depending on the temperature and pressure.
Calculate the number of molecules in 2.00 moles H2S.
Express your answer numerically in molecules.
Answer:
The answer is
1.204 × 10²⁴ moleculesExplanation:
The number of molecules can be found by using the formula
N = n × Lwhere n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
N = 2 × 6.02 × 10²³
We have the final answer as
1.204 × 10²⁴ moleculesHope this helps you
How for way is the Neptune from the sun