Since hardness measurement involves only surface of the material, bulk density of the material does not have any explicit relation with the hardness. Materials are usually subjected to microstructural and/or chemical changes in the surface by carbiding, nitriding and other processes, many times by cold working.
The structure of the surface of the material is almost always different from the structure inside the bulk, it would be a very complicated and complex relationship, if anyone ever tries to establish it and may not prove that beneficial also
What is an isotope?
A. atoms of the same element that have similar chemical properties but have different
numbers of protons
B.atoms of the same element that have similar chemical properties but have different
numbers of electrons
C. atoms of the same element that have similar chemical properties but have different
numbers of neutrons
Answer: C.
Explanation:
They are the same elements that contain same number of protons, but different numbers of neutrons.
Why does Earth get more energy from the sun than from all the other stars in the universe combined?
A.) The sun is much hotter than the other stars.
B.) The sun is much more dense than the other stars,
C.) The sun is much closer than the other stars.
D.) The sun is much larger than the other stars,
Answer:
C
Explanation:
C is correct because it is extremely close compared to other stars, the closest at 23 light-years(the distance from the Earth to the sun) away.
The earth gets more energy from the sun than from all the other stars in the universe combined because the sun is much closer than the other stars.
The universe is composed of several stars. These stars are at various distances from the earth.
The earth is closest to the sun. The distance between the earth and the sun is about 93,000,000 miles or 150,000,000 km.
Owing to the proximity of the sun and the earth, the earth get more energy from the sun than from all the other stars in the universe combined.
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four main states of matter?
Answer:
Solid, liquid, gas, and matter!
Explanation:
i hope i helped!
Answer: Solid, Liquid, Gas, and Plasma
Explanation:
Which best describes the law of conservation of mass? (1 point)
The coefficients in front of the chemicals in the reactants should be based on the physical state of the products.
O Products in the form of gases are not considered a part of the total mass change from reactants to products.
Owhen reactants contain both a solid and a liquid, the solid counts toward the overall mass and the liquid does not.
The mass of the reactants and products is equal and is not dependent on the physical state of the substances.
D: The mass of the reactants and products is equal and is not dependent on the physical state of the substances.
Explanation:
Answer:
Its D
Explanation:
Just took the test
What elegant has 2 valence electrons
Explanation:
Calcium is the element that has 2 valence electrons.
The Milky Way galaxy is described as a disk of stars orbiting a central point on the disk. Which of these best explains
why people on Earth cannot see the entire shape of the Milky Way?
A.) Many more stars exist outside the galaxy.
B.) Earth is a part of this galaxy.
C.) The stars in the center of the galaxy are extremely small.
D.) The center of the galaxy consists of a dense cluster of stars.
Answer:
b
Explanation:
Answer:
b
Explanation:
How is gold different than the other types of matter
Answer:
Gold is different than other because they are homogenous mixture.
How are the properties of organic compounds determined?
Explanation:
The physical properties of organic compounds typically of interest include both quantitative and qualitative features. Quantitative information includes a melting point, boiling point, and index of refraction. Qualitative properties include odor, consistency, solubility, and color.
Which verb describes a process that is NOT indicative of a chemical change?
a) ferment
b) burn
c) rot
d) melt
Answer:
melt
Explanation:
i got it right on CK-12
A substance's color changing is not always an indication of a chemical change. Changing the color of a metal, for example, has no effect on its physical properties. Melt is not indicative of a chemical change.
What is melting point ?The typical definition of the melting point is the temperature at which a substance changes from a solid to a liquid.
The melting point of a liquid is the temperature at which the liquid converts from a solid to a liquid above atmospheric pressure. At this period, both the liquid and solid phases are in a thermodynamic equilibrium.
The melting point is frequently used to forecast a chemical's behavior when it changes between the solid and gas phases. Higher intermolecular forces and hence lower evaporation rate are indicators of higher melting values.
Thus, option D is correct.
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Which of the following properties are found in ionic compounds?Immersive Reader
A- Formation of molecules
B- Low melting point
C- Doesn't dissolve in water
D-High melting point
Answer:
High melting point is answer
Which of these statements is false?
A.
The discovery of the first noble gas prompted the discovery of the others.
B.
Technology speeds up element discovery.
C.
Particle accelerators are used to synthesize elements.
D.
There are 22 groups on the periodic table.
Answer:
D
Explanation:
There are actually 8 groups on the periodic table. Meaning choice D is the correct answer.
Which are steps of mitosis? Select 4 options.
prophase
metaphase
interphase
anaphase
telophase
Answer:
Prophase, metaphase, anaphase, telophase
Explanation:
An arc subtends a central angle measuring 3pi/2 radians. What fraction of the circumference is this arc? of the circumference
Answer:
3/4
Explanation:
Answer:
3/4
Explanation:
Got it right on Khan Academy
Brainlest if Correct
4. The periodic table is organized into groups and periods of elements. The point
characteristics of a certain group of elements are listed below. Which of
these elements is in this group?*
Characteristics of a Group of Elements
• Is shiny
• Is solid at room temperature
• Has atoms with two valence electrons
O A Lithium
O B. Strontium
O C. Aluminum
O D. Silicon
Answer:B
Explanation:
Tungsten (W), Copper (Cu), and Iron (Fe) all belong to the same family, whose members are generally used as conductors of electricity. What family is this?
Answer:
Transition metals.
Explanation:
Conductor of electricity typically refers to any material or object that allow the conduction (transfer) of electric charge.
Tungsten (W), Copper (Cu), and Iron (Fe) all belong to the same family, whose members are generally used as conductors of electricity. This family is known as transition elements.
The transition elements refers to the chemical elements found in group III to XII (3-12) of the periodic table and typically has a d-orbitals (d subshell) that is partially filled with electrons.
Tungsten (W), Copper (Cu), and Iron (Fe) belongs to the family of transition metals.
Conductors of electricity are object or substance that conduct electricity. Currents can flow through them efficiently.
The Elements Tungsten (W), Copper (Cu), and Iron (Fe) all belong to the group/family called transition metals.
Transition metals forms one or more stable ions and they have incompletely filled d orbitals.
Generally, transition metals are good conductor of electricity. They are very good catalyst for chemical reaction.
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Which statement explains the kinetic theory of heat? Objects whose particles are at the same temperature are in thermal equilibrium. Objects are made of tiny particles, and their motion depends on the temperature. An object's thermal energy is caused by the movement of the tiny particles that it is made of. Heat is transferred as thermal energy by the interaction of moving particles.
Answer:
Which statement explains the kinetic theory of heat?
A)Objects whose particles are at the same temperature are in thermal equilibrium.
B) Objects are made of tiny particles, and their motion depends on the temperature.
C) Heat is transferred as thermal energy by the interaction of moving particles.
D) An object's thermal energy is caused by the movement of the tiny particles that it is made of.
YOU ANSWER IS (C) "heat is transferred as thermal energy by the interaction of moving particles"
Explanation: I TOOK THE K12 TEST ENJOY !!!!
Answer:
Heat is transferred as thermal energy by the interaction of moving particles.
Explanation:
I took the test
Forensic means _______ the forum
1. What number of molecules of O2 is consumed when 33.6 liters of STP H2O is
produced according to the following reaction:
4 NH3(g) + 502 (g)
-------> 4 NO S
+ 6H20 g
Pleassss answerrr!!
Answer:
x= 5.418*10^24
Explanation:
x * (22.4*6) = 33.6*(6.02*10^23 * 5)
x= 5.418*10^24
The number of moles of oxygen to produce 33.6 L water is 1.25. The number of oxygen molecules in 1.25 moles is 7.52 × 10²³.
What is STP condition?The condition of standard temperature temperature and pressure STP is the 298 K and 1 atm pressure. At this condition one mole of every substances contains 22.4 L of volume.
As per the given reaction 5 moles or 5 × 22.4 = 112 L is needed to produce 6 moles or 6 ×22.4 = 134.4 L of water at STP. Hence, the volume of oxygen required to produce 33.6 L of water is:
volume of oxygen = (33.6 l× 112 l)/134.4 l
= 28 L.
28 L of oxygen is 28/22.4 = 1.25 moles of oxygen at STP. One mole of oxygen gas contains 6.022 × 10²³ molecules. Hence, number of molecules in 1.25 moles is:
1.25 × 6.022 × 10²³ = 7.52×10²³.
Therefore, 7.52×10²³ molecules of oxygen gas will be consumed to produce 33.6 L of water at STP.
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Which statement correctly describes the nucleus of the atom?
A) The nucleus of the atom contains the electrons.
B) The nucleus of the atom is mostly empty space.
C) The nucleus of the atom surrounds the center of the atom.
D) The nucleus of the atom contains most of the mass of an atom.
Answer:
llllllllllkkkll
(Answer:D)
What 12 letter word explains the protection of animals and resources here on Earth?
___________________________________
Based on the Law of Conservation of Matter, why do you think the weight of Steel Wool would change the way it did?
Answer:
Because matter cannot be destroyed or created, It can change form through physical, chemical changes but the matter never gets destroyed or created.
Explanation:
what family are the elements carbon, germanium and lead in?
Answer:
Damian here!! :))
The carbon family consists of the elements carbon (C), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), and flerovium (Fl). Atoms of elements in this group have four valence electrons. The carbon family is also known as the carbon group, group 14, or the tetrels. Elements in this family are of key importance for semiconductor technology.
Explanation:
Hope this helps? :))
Answer:
a carbon group element, any of the six chemical elements that make up Group 14 (IVa) of the periodic table—namely, carbon (C), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), and flerovium (Fl).
Explanation:
have a good day
might be hard to read but i do not understand what the “K” means.
it means kinetic energy
Answer:
k means. crores
Explanation:
it. is. very easy
how might the atoms that make up bones be different from the atoms that make up soft tissue?
The atoms that make up soft tissue are smaller and are incapable of absorbing X-rays while atoms that make up bones are more capable of absorbing X-rays.
X-rays belong to the electromagnetic spectrum. They are composed of high energy radiation which penetrates soft tissue but are readily absorbed by the calcium atoms in the bone.
The soft tissue are composed of smaller atoms which can not absorb X-rays. Hence, X-rays can pass through soft tissue and reach the bone where calcium atoms can absorb them quite well.
This absorption of X-rays in bones is very important in medicine.
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How are stalactites formed?
Answer:
Explanation:
As the redeposited minerals build up after countless water drops, a stalactite is formed. If the water that drops to the floor of the cave still has some dissolved calcite in it, it can deposit more dissolved calcite there, forming a stalagmite.
Manganese-56 decays by beta emission and has a half-life of 2.6 hours. How many half-lives are there in 24 hours? How many mg of a 20.0 mg sample will remain after five half-lives?
Explanation:
Given that,
Manganese-56 decays by beta emission and has a half-life of 2.6 hours.
We need to find no of half lives in 24 hours. It can be calculated by dividing 24 hours by 2.6 hours. So,
[tex]T=\dfrac{24}{2.6}=9.23\ \text{half lives}[/tex]
Let x mg of a2 0 mg sample remain after 5 half-lives.
[tex]x=20\ mg\times \dfrac{1}{2^5}\\\\x=0.625\ \text{mg}[/tex]
Hence, there are 9.23 half lives and 0.625 mg of sample will remain after 5 half lives.
What are the products of the combustion of a hydrocarbon?
a) carbon and oxygen
b)carbon dioxide and water
c)carbon and hydrogen
d) carbon dioxide and hydrogen
Answer:
its b
Explanation:
i got a 100 percent
The products of the combustion of hydrocarbon are carbon dioxide and water. Therefore, option (b) is correct.
What is the combustion reaction?A combustion reaction is a reaction that produces fire and takes place at an elevated temperature. It is an exothermic, redox chemical reaction that usually occurs between a fuel and mostly oxygen in the atmosphere.
Examples of Combustion Reactions such as during the combustion of methane reacts with two molecules of oxygen gas to give carbon dioxide and two molecules of water.
[tex]CH_4(g) + 2O_2(g) \longrightarrow CO_2 (g) + 2 H_2O (g)[/tex]
Oxygen is the main ingredient for the combustion reaction because combustion cannot happen in the absence of oxygen. Complete combustion occurs when a fuel burns completely to produce carbon dioxide and heat with oxygen.
The burning of wood or solid fuels is an example of combustion. The carbon present in wood or coal reacts with oxygen in the air to release heat and form gaseous products.
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2 A bee consumes nectar from a flower.
Which of the following was described
A. Two organisms competing for food
B. A producer helping another producer
C. An organism interacting with a nonliving
component of its ecosystem
D. An organism depending on another organism
for energy
This is science but there is no choice for this subject.
How many 15W LED bulbs could Niagara Falls power?
Complete question is;
Water flows over Niagara Falls at the average rate of 2,400,000 kg/s, and the average height of the falls is about 50 m. Knowing that the gravitational potential energy of falling water per second = mass (kg) x height (m) x gravity (9.8 m/s²), what is the power of Niagara Falls? How many 15 W LED light bulbs could it power?
Answer:
A) Power of Niagara Falls = 1.176 × 10⁹ W
B) 78.4 × 10⁶ bulbs
Explanation:
A) We are given;
The mass flow rate of Niagara falls = 2,400,000 kg/s
The average height of the fall = 50 meters
Gravitational potential energy = mass (kg) x height (m) x gravity (9.8 m/s²)
Now, formula for power is; workdone/time taken.
Thus it's potential energy/time taken.
Hence;
Power = (mass (kg) x height (m) x gravity (9.8 m/s²))/time(s)
We know that mass/time is mass flow rate.
Thus; power = mass flow rate (kg/s) × height (m) × gravity (9.8 m/s²)
Thus;
Power of Niagara Falls = 2400000 × 50 × 9.8 m/s²
Power of Niagara Falls = 1.176 × 10⁹ W
B) The number(n) of 15 W LED light bulbs Niagara falls could power is given by the relationship;
n × 15 W = 1.176 × 10⁹ W
Thus;
n = 1.176 × 10⁹ W/(15 W)
n = 78.4 × 10⁶ light bulbs
The number of 15 W LED light bulbs Niagara falls could power = 78.4 × 10⁶ bulbs
how to find out number of protons , neutrons and electrons?
Answer:
The number of protons in the nucleus of the atom is equal to the atomic number (Z). The number of electrons in a neutral atom is equal to the number of protons. The mass number of the atom (M) is equal to the sum of the number of protons and neutrons in the nucleus
