Chemical reactions are the various types of permanent changes which occur in substances and which produce new substances .
What are chemical reactions?Chemical reactions are changes which occur in the arrangement of atoms in a substance resulting in the formation of new substances.
There are many types of chemical reactions such as:
combination reactionsdisplacement reactionsdecomposition reactionsoxidation reactionsdouble displacement reactionsThe various types of chemical reactions that occur contribute to the numerous compounds and substance in existence today.
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What is Avogadro’s number?
A. the number of atoms in exactly 14.00 g of carbon-12
B. the number of atoms in a kilogram of any substance
C. the number of atoms, molecules, ions, formula units, or other particles in a mole of a substance
D. the number of atoms, molecules, ions, formula units, or other particles in a gram of a substance
Answer:
C
Explanation:
A lithium atom contains 3 protons , 4 neutrons and 3 electrons
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Answer:
B
Explanation:
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What type of heat is used to cook pancakes?
Answer choices :
A. Conduction
B. Convention
C. Radiation
Answer:
A
Explanation:
Answer:
conduction (A) is the right answer
Helppppp please!!!!!!!
For the first question:
Use the formula: Density = Mass/Volume
Given in the question:
Mass - 1800 mg
Volume - 2 cm3
Calculation
Density = Mass/Volume
= 1800/2
= 900mg/cm3
Therefore, the density is 900mg/cm3.
Plz help getting timed
Answer:
I think the first one is Active Transport.
Explanation:
The second one is passive transport
L avanzar hacia la derecha por el período 5, el tamaño atómico, la energía de ionización y los electrones de valencia: A. disminuye, aumenta y aumentan, respectivamente. B. aumenta, disminuye y disminuye, respectivamente. C. disminuye, disminuye y aumentan, respectivamente. D. disminuye, aumenta y disminuyen, respectivamente.
Answer:
Al avanzar hacia la derecha por el período 5, el tamaño atómico, la energía de ionización y los electrones de valencia: A. disminuye, aumenta y aumentan, respectivamente.
Explanation:
El radio atómico representa la distancia que existe entre el núcleo y la capa de valencia, es decir la más externa. Por medio del radio atómico es posible determinar el tamaño del átomo. En un período el tamaño atómico disminuye de izquierda a derecha pues en este sentido aumenta el número atómico aumentando la carga nuclear mientras que el efecto pantalla y el número de niveles permanecen constantes. En otras palabras, disminuye de izquierda a derecha debido a la atracción que ejerce el núcleo sobre los electrones de los orbitales más externos, disminuyendo así la distancia núcleo-electrón.
Al avanzar hacia la derecha por el período 5, el tamaño atómico disminuye.
La energía de ionización es la necesaria para remover un electrón a un átomo en estado gaseoso. Mientras más lejos del núcleo esté el electrón, es más fácil removerlo porque se necesita menos energía. Al aumentar el número atómico de los elementos de un mismo período, se incrementa la atracción nuclear sobre el electrón más externo, ya que disminuye el radio atómico y aumenta la carga nuclear efectiva sobre él. Entonces en un período, al aumentar el número atómico, la energía de ionización aumenta.
Entonces, al avanzar hacia la derecha por el período 5, la energía de ionización y los electrones de valencia aumenta.
Los electrones de valencia son los electrones que están en la última capa electrónica (llamados orbitales de valencia) y tienen una alta posibilidad de participar en una reacción química.
En cada período aparecen los elementos cuyo último nivel de su configuración electrónica coincide con el número del período, ordenados por orden creciente de número atómico. Por ejemplo, el período 3 incluye los elementos cuyos electrones más externos están en el nivel 3.
Los electrones de valencia aumentan en número a medida que se avanza en un período.
Entonces, al avanzar hacia la derecha por el período 5, los electrones de valencia aumentan.
12. Several isotopes of a certain atom "X" exist. 4.35% of all X atoms have a mass of 39.946 amu.
83.79% have a mass of 41.941 amu, 9.50% have a mass of 42.941 amu, and 2.36% have a mass of
43.939 amu. What is the average atomic mass of atom X?
Answer: 41.97
Explanation:
which ion has the smallest radius
2. How much ice will 7 cups of water make?
Answer:
6.44 cups of ice
Explanation:
The ratio of the densities is simply the density of one divided by the density of the other: The density of ice to water is 0.92. Using the ratio, one can simply multiply the volume of the ice by 0.92, which is the conversion factor for the volume of ice to liquid water.
7 × 0.92 = 6.44
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What is the what is what and why
Answer:
what
Explanation:
is this free points
Please help me answer this chemistry question:
Which of the following particles Are free to drift in metals
Astrology is the study of how the positions of the stars and movements of the planets influence the lives and behaviors of people. Astrology dates back to the second millennium BCE. Modern Western astrology is often associated with horoscopes that explain an individual’s personality and predict significant events in his or her life based on the position of stars and planets. There is no evidence to support the validity of astrology or its methods. Is astrology an example of science or pseudoscience? Explain your answer.
Answer: Astrology is an example of pseudoscience. It is based on beliefs and is not supported by any scientific evidence.
how many atoms are there in 6.8 mole of boron
What can you infer on the materials that clings unto the magnets? What made you say so?
When you are done looking at slides of blood smears you should _____.
1 wash the slides off in the sink
2 leave the slides for someone else to clean up.
3 dispose according to your teacher’s instructions
4 dump in the trash
pls help
Answer:
Hello!!! Princess Sakura here ^^
Explanation:
The answer is Choice 3. the teacher will give you the most safe instructions according to how dangerous the blood might be.
There are many types of forces. Which statement best compares an electrical force to gravitational force?
A. Electrical forces hold small objects near eachother and gravitational forces hold large objects near each other.
B. Electrical forces depends on the type of charge and gravitational forces depend on the mass of the objects and how far apart they are.
C. Electrical forces are attractions between similar types of charges and gravitational forces are attractions between similar size of objects.
D. Electrical forces require that the objects are in contact with eachother and gravitational forces require the objects are far from each other.
How do you call when a substance goes from a solid to a liquid?
Answer:
Melting point as a chemistry concept
The solid begins to go from a solid state to a liquid state — a process called melting. The temperature at which melting occurs is the melting point (mp) of the substance.
1 pt
Question 5
Aurora records the following observations: It rained on Monday. It was sunny on
Tuesday. It rained again on Wednesday: What is Aurora recording?
A) weather
B) neither weather or climate
C) both weather and climate
D) climate
Answer: D. Climate
Explanat
Which of the following is an excited state electron configuration for Iron (Fe)?
a)2-8-18-2
b)2-8-14-2
c)2-8-7-5
d)2-8-10-6
All atoms of the same element:
have the same number of atoms
have the same number of neutrons
have the same number of electrons
have the same number of protons
Answer:
have the same number of protons
Explanation:
The number of protons in an atom determine what element it is. The number of electrons and neutrons can vary from atom to atom of the element, as long as all the atoms have the same number of protons.
The base camp is located 5,300 meters above sea level. The hiker observes that the water begins to boil at 82⁰C, much lower than the 100⁰C needed to cook the raw egg. He hopes that just leaving the egg in the boiling water longer will let the egg cook. Will he have hard-boiled eggs for breakfast?
Answer:
No he will not have hard boiled eggs for breakfast
Explanation:
The temperature required to boil the eggs is about 100⁰C. Unfortunately, at the height of the base camp (5,300 meters), water boils at 82⁰C.
This implies that the egg will not become cooked as at the time when the water begins to boil.
Since the eggs can only become hard boiled at 100⁰C and the temperature at which water boils at 5300 meters is less than that(82⁰C), the eggs can not become hard boiled.
what is physical and chemical change ?
Answer:
Physical change is there is a difference in appearance, smell, etc.
Chemical change is there is change in the composition or the rearrangement of the atoms of one or more substances.
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Answer:
sksksk
Explanation:
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Answer:
Try putting Dd okkkkkkkk
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Why do nitrogen molecules have triple bonds, whereas oxygen molecules have double bonds? How many valence electrons does each atom have, and how does that affect the type of bond formed in each molecule? Draw Lewis dot diagrams to support your answer
Answer:
Nitrogen is a diatomic molecule in the VA family on the periodic table. Nitrogen has five valence electrons, so it needs three more valence electrons to complete its octet. A nitrogen atom can fill its octet by sharing three electrons with another nitrogen atom, forming three covalent bonds, a so-called triple bond.
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Answer:
Two covalent bonds form between the two oxygen atoms because oxygen requires two shared electrons to fill its outermost shell. Nitrogen atoms will form three covalent bonds (also called triple covalent) between two atoms of nitrogen because each nitrogen atom needs three electrons to fill its outermost shell.
The number of electrons in an atom's outermost valence shell governs its bonding behaviour. Elements whose atoms have the same number of valence electrons are grouped together in the Periodic Table. ... To form a covalent bond, one electron from the halogen and one electron from another atom form a shared pair.
What is methane? Where is it found?
Answer:
Methane is an odorless, colorless, flammable gas. It is used primarily as fuel to make heat and light. It is also used to manufacture organic chemicals. Methane can be formed by the decay of natural materials and is common in landfills, marshes, septic systems and sewers
Explanation:
In the early 1900's many scientists thought that an atom consisted of a positive substance with negative charges scattered throughout the substance. Then Ernest Rutherford completed an experiment that changed the concept of an atom. His discovery led to the understanding that an atom. His discovery led to the understanding that an atom consists of mostly empty space with
The question is incomplete; the complete question is;
In the early 1900s many scientists thought that an atom consisted of a positive substance with negative charges scattered throughout the substance. Then Ernest Rutherford completed an experiment that changed the concept of an atom. His discovery led to the understanding that an atom consists mostly of empty with space with-
Protons orbiting a dense nucleus made of electrons and neutrons
Electrons orbiting a dense nucleus made of protons and neutrons
Neutrons and protons orbiting a cloud of electrons
Electrons and protons orbiting a cloud of neutrons
Answer:
Electrons orbiting a dense nucleus made of protons and neutrons
Explanation:
Rutherford established the nuclear theory of the atom by his famous experiment. In his experiment, alpha particles were used to bombard a thin gold foil and the movement of the particles was observed on a moveable zinc sulphide screen.
It was discovered from the experiment that the atom was mostly made up of empty space. The electrons orbit a dense nucleus comprising of protons and neutrons.
How do scientist determine the ages of fossils
Answer:
Relative dating is used to determine a fossils approximate age by comparing it to similar rocks and fossils of known ages. Absolute dating is used to determine a precise age of a fossil by using radiometric dating to measure the decay of isotopes, either within the fossil or more often the rocks associated with it.