Answer:
Models are important in the study of science because they explain a scientific phenomenon that is not directly experienced.
Explanation:
A Model in science is an idea, a process or a system applied by scientists to test hypothesis of a certain phenomenon in study. A model can be used to predict information using the data obtained. However, it is important to mention that after testing a model , a scientist can improve it using new data obtained in the area of study. Models are therefore a vital part of scientific research and the results communicated when explaining a phenomenon.
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 elegant has 2 valence electrons
Explanation:
Calcium is the element that has 2 valence electrons.
Placing a sample of iron (ll) oxide into a graduated cylinder makes the water volume increase 12.0 mL. The weight of the sample is 76.6 g. What is its density?
Answer:
The answer is
3.83 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\[/tex]
From the question
mass = 76.6 g
volume = 12 mL
The density of iron (ll) oxide is
[tex]density = \frac{76.6}{12} \\ = 6.38333333...[/tex]
We have the final answer as
6.38 g/mLHope this helps you
Answer:
he answer is
3.83 g/mL
Explanation:
The density of a substance can be found by using the formula
From the question
mass = 76.6 g
volume = 12 mL
The density of iron (ll) oxide is
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
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 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.
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 is gold different than the other types of matter
Answer:
Gold is different than other because they are homogenous mixture.
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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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.
Which are steps of mitosis? Select 4 options.
prophase
metaphase
interphase
anaphase
telophase
Answer:
Prophase, metaphase, anaphase, telophase
Explanation:
Which is the largest in size? OA. A. a star O B. a planet O c. an asteroid D. a galaxy E. a supernova E.
Answer:
galaxy
Explanation:
galaxy is the largest in size
Why would a scientist want to identify this species of spider? Check all that apply. to be certain that it is a spider to compare it to similar spiders to determine the relationship it has with other organisms to determine if the spider is safe to handle or not to find out how many offspring it has had this year
Answer:
-To compare it to similar spiders
-To determine the relationship it has with other organisms
-To determine if the spider is safe to handle or not
Explanation:
Answer: 2 3 4
Explanation:
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
four main states of matter?
Answer:
Solid, liquid, gas, and matter!
Explanation:
i hope i helped!
Answer: Solid, Liquid, Gas, and Plasma
Explanation:
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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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.
What 12 letter word explains the protection of animals and resources here on Earth?
___________________________________
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
if you have a volume of 10 ml and a mass of 100 kg, what is the density.
An object of mass 10kg whirled round in a horizontal circle of radius 4m by a revolving
String inclined to the vertical. If the uniform speed of the object is 5m/s.Calculate the tension of the string.
Answer:
114N is correct answer.
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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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
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
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
The density of aluminum is 2.70 g/mL. If you use 108 g of aluminum foil, what is its volume in mL?
Question 13 options:
0.642 mL
292 mL
40.0 mL
2.50 mL
Answer:
volume =40.0 ml
Explanation:
density = mass/ volume
volume = mass/ density
volume = 108/ 2.70
volume =40.0 ml
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.
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:
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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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:
