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 made a discovery that led to the understanding that an atom consists mostly of empty space with- * 20 points A. protons orbiting a dense nucleus made of electrons and neutrons B. Neutrons and protons orbiting a cloud of electrons C. Electrons and protons orbiting a cloud of neutrons D. Electrons orbiting a dense nucleus made of protons and neutrons
Answer:
D(pretty sure)
Explanation:
SCIENCE!! i need help on the question in the middle please!!!
as u move down the levels of classification the number of classification the number of organisms in the level decrease or increase?
Answer:
decrease
Explanation:
Which statement correctly describes the location and charge of a proton in an atom? A. The protons are inside the nucleus with a negative charge. B. The protons are inside the nucleus with a positive charge C. The protons are outside the nucleus with a negative charge. D. The protons are outside the nucleus with a positive charge.
Answer:
The correct answer is B
Explanation:
A group of people take a diet pill. After 3 months, they measure the amount of weight they lost.
A :Independent Variable:
B: Dependent Variable:
dependent variable I think
Write down Newton’s second law and its equation.
Answer: a = Fnet/m
Explanation:
The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object. This verbal statement can be expressed in equation form as follows: a = Fnet / m.
Which statement is true about the model of the atom below? * 20 points Captionless Image A. Positively charged particles are found outside the center of the atom. B. Negatively and positively charged particles are found in the center of the atom. C. Neutral and positively charged particles are found in the center of the atom. D. Neutral particles are found outside the center of the atom.
Which statement best describes properties of elements? A) All elements have a similar structure and hardness. B) All elements are either metals or gases. C) All elements are solid and magnetic. D) All elements have mass and occupy space
Answer:
D
Explanation:
That is the right answer
WILL GIVE BRAINLIEST
List three examples of where potential energy is transformed to kinetic energy in the Rube Goldberg Machine simulation. Fully explain the energy transformations using complete sentences. (Example: The ball has potential energy when it sits on the shelf that transforms to kinetic energy when it falls to the ground.)
DO NOT COPY AND PAST THE ANSWER FROM 2018 AND IF YOU HAVE A QUSTOIN ABOUT IT ASK UNDER THE QUSTION DO NOT ANSWER IT TO ASK A QUSTION
Answer:
1. The ball will have potential energy at the top of the mountain, when the ball falls the ball will have kinetic energy .
2. The roller coaster has potential energy when stopped on the very top, therefore it releases kinetic energy when it falls down the rollercoaster.
3. The car on the hill had potential energy weather when it went down it had kinetic energy.
Explanation:
Sorry it took forever I had to think lol..
Answer:
ok lol
im bored
Explanation:
Which equation using element symbols correctly describes the reaction: "One molecule of methane plus two molecules of diatomic oxygen react to form two molecules of water and one molecule of carbon dioxide?"
Answer:
CH4+2O2→2H2O+CO2
What is the chemical symbol for table salt?
Answer: NaCI
Explanation:
Answer: NaCl
Sodium chloride , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions.
Which property describes a mixture? It cannot be separated by physical methods. It has a single chemical composition. It cannot have more than one state of matter. It cannot be described by a chemical symbol or formula.
Answer:
it cannot be separated by physical methods
Explanation:
The mixture is not separated from the physical methods. Thus, option A is correct.
A mixture has been the combination of two or more substances. It has been described as a homogeneous solution.
The constituents in the mixture are indispensable. The mixture is generally homogeneous, however, heterogeneous mixtures have been possible with the substances being separated.
The mixtures have a different chemical composition and are not separated from the physical methods. Thus, option A is correct.
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Which two models would be most useful in predicting weather?
A. A mathematical model based on data
B. A plastic model of a cloud
C. A map that shows wind patterns
D. A peach used to represent Earth
Answer:
A. A mathematical model based on data
A mathematical model based on data and a map that shows wind patterns would be most useful in predicting weather as it they will provide data with most accuracy.
What is accuracy?
Accuracy in terms of chemistry can be defined as to how close a measurement is to the true value.There are three types of accuracy:
1) Point accuracy-It means accuracy is present at that point of scale only.It does not give any information about the accuracy of the instrument.
2)Percentage of true value--It is the accuracy which is determined by identifying accuracy of the instrument and comparing it with the measured true value.
3)Percentage of scale range- It is the accuracy which determines accuracy of the measurement.
Accuracy in case of instruments is neglected up to ±0.5 percent.
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DO NOT ANSWER IF YOU DO NOT KNOW WHAT TO DO
Answer:
im gunna save my answer so no one can take it:)
Explanation:
I tried my best
Answer:
Wxvylaura
Explanation:
They are correct listen to them
What is the formula name!!
I will give brainliest !!…
Answer:
I think this is the formula CH₃COOH.
Explanation:
Obi is trying to determine if a powdery, solid substance is an element or a compound. After recording some observations, he strongly heats a sample of the solid over a burner flame. After fifteen minutes, he turns off the flame and allows the sample to cool. He records his final observations in the data table.
A 3-column table with 3 rows. The first column labeled observation has entries appearance, mass (g), chemical reaction with weak acid. The second column labeled original sample has entries white solid, 100.0, bubbles. The third column labeled sample after heating has entries white solid, 56.0, no bubbles.
Which is the best explanation of his results?
A. The heating changed some of the sample to gas, causing the mass to decrease without breaking down the sample. Therefore, the original sample is a compound.
B. The appearance stayed the same, showing that the sample was not broken down by heating. Therefore, the original substance is an element.
C. The mass decreased during heating and some of the impurities escaped. Therefore, the original substance is an element.
D. The chemical reaction with acid changed, showing that the sample was broken down by heating. Therefore, the original substance is a compound.
An element consists of one type of atom and cannot be broken into simpler substances through simple chemical processes
The correct option is option D
D. The chemical reaction with acid changed, showing that the sample was broken down by heating. Therefore, the original substance is a compound
The reason why option D is correct is as follows:
The given table is presented as follows;
[tex]\begin{array}{|l|l|l|}\mathbf{Observation}&\mathbf{Original \ Sample}&\mathbf{Sample \ After \ Heating}\\Appearance&White \ solid&White \ solid\\Mass&100 \, g&56 \, g\\Chemical \ reaction \ with \ acid&Bubbles&No \ bubbles\end{array}\right][/tex]
Given that the changes after heating includes lack of visible reaction with the weak acid, and a significant change in mass, therefore;
The original substance was broken down by heat resulting in a new substance that has different chemical properties. An element cannot be broken down into simpler substances. Therefore, the substance is a compound
The correct option is option D
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Two students make a model of a tree house they want to build. The sale is 1:44. In the scale model, the tree house has 2 windows. How many windows should be the real tree house have?
A. 22
B. 88
C. 4
D. 2
The data table shows the number of pumpkin seeds that germinate at different temperatures. What is the median number of seeds that germinate at 32ºC?
A. 64
B. 65.5
C. 65
D. 66
Answer: I agree with the other person it's B
As the toy car rolls away, it slows down. Why?
Answer:
Friction
Explanation:
Depending on the material the toy car rolls away on, the more friction is created, the more friction there is, the more on surface rubs against another, creating friction, slowing it down
hope this helps
In which chemical equation is the number of atoms in the reactants the same as the number of atoms in the products?(1 point)
A) Zn + 2HCl → H2 + ZnCl2
B) CH4 + O2 → CO2 + 2H2O
C) Li2CO3 → LiO + CO2
D) CO2 + H2O → CH2OH + O2
2. Which statement is true regarding a chemical reaction?(1 point)
A) Even if the total number of atoms does not change, mass may not be conserved in the reaction.
B) Even if the total number of atoms changes, mass may not be conserved in the reaction.
C) The total number of atoms changes, so mass is conserved in the reaction.
D) The total number of atoms does not change, so mass is conserved in the reaction.
3.
Use the equation and the table to answer the question.
FeCl3 + 3H2O → Fe(OH)3 + 3HCl
Element Mass of an Atom (amu)
Fe 56
Cl 35
H 1
O 16
Iron chloride and water react according to the equation shown. The table shows the atomic masses of the elements involved in the reaction. What is the total mass of the reactants?
(1 point)
A) 215 amu
B) 179 amu
C) 161 amu
D) 108 amu
4. In a chemical reaction, two molecules with a total mass of 76 amu react to form a single molecule. What is the mass of the molecule that is formed?(1 point)
A) 228 amu
B) 38 amu
C) 76 amu
D) 152 amu
Answer:
There are many types of chemical reactions. In this chapter we will begin with combustion
reactions and end with oxidation/reduction reactions. Along the way we examine various aspects
of reactions.
Homework from the book:
Exercises: 1, 4, 6, 8, 9, 11,12, 14-19, 23, 25, 26, 29
Questions: none
Problems: none
In the study guide: Multiple 4, 5, 6, 12-18.
There are many types of chemical reactions. In this chapter we will begin with combustion
reactions and end with oxidation/reduction reactions. Along the way we examine various aspects
of reactions.
Combustion reactions:
All combustion reactions fall into the pattern:
fuel + O2 → CO2 + H2O
The coefficients of the balanced equation will change depending on the fuel. The fuel can be
almost anything including methane (CH4), propane (C3H8), butane (C4H10), octane (C8H18) or
sugar (C6H12O6).
The balanced equation for methane is CH4 + 2 O2 → CO2 + 2 H2O
The balanced equation for octane is
2 C8H18 + 25 O2 → 16 CO2 + 18 H2O
The combustion of methane or octane is exothermic; it releases energy.
CH4 + 2 O2 → CO2 + 2 H2O + energy
The energies of the products are lower than the energiies of the reactants. The excess energy is
released as heat and light.
Matter tends to move to lower energy states. A good analogy for a reaction is a ball falling down
a hill. Exothermic reactions are more likely to occur. Endothermic reactions absorb energy. In
these reactions the products are higher in energy than the reactants. Endothermic reactions are
less likely to occur. You seldom see a ball spontaneously going uphill. Endothermic reactions
can occur when entropy drives the reaction (pushes the ball up the hill). These reactions are far
less common. An exothermic reaction occurs in a chemical hot pack. (Skiers know about hand
and foot warmers.) An endothermic reaction occurs in a chemical cold pack.
The reaction in which the number of atoms are equal in both side is option A. The true statement regarding a chemical reaction is option D mass is conserved.
The total mass of reactants for the given reaction is 179 g. The mass of the molecule formed will be 76 amu.
What mass conservation?According to law of conservation of mass the total mass of the reactants is equal to the total mass of products in a reaction. No atoms are created or destroyed in a reaction.
1. The reaction in which the number of atoms are same on both side is option A, where both part contains 5 atoms.
2. According to mass conservation law, total number of atoms does not change, thus mass is conserved and option D is correct.
3. The atomic mass of Fe = 56 amu and the atomic mass of Cl = 35 amu. Mass of 3 Cl = 3×35 = 105 g
Thus mass of FeCl3 = 105 + 56 = 161 amu.
Mass of H = 1 amu and mass of O = 16 amu. Thus mass of 3 H2O = (3×(16+2)) =54 amu
Thus total mass = 54 + 161 = 215 amu
Thus, option A is correct.
4. According law of conservation of mass the total mass of reactant is equal to the total mass of products. Thus reactants of total mass 76 amu produce product of mass 76 amu. Thus option C is correct.
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What has to happen for these atoms/molecules to change from one state of matter to another? *view attachment*m
Answer:thermal energy has to be added or transferred
Explanation:I’m not sure you might want to double check but the reason I chose thermal energy is because when thermal energy is added to liquid it may dissolve into gas
Please match the example with the classification of matter in which it belongs. Column A 1. soil: soil 2. chocolate milk: chocolate milk 3. neon: neon 4. water: water Column B a.element b.homogeneous c.compound d.heterogeneous mixture
Answer:
34
Explanation:
add
What causes objects to move or stay still?
Claim
Reasoning:
Evidence:
Answer:
For an object to move, there must be a force. A force is a push or pull that causes an object to move, change direction, change speed, or stop. Without a force, an object that is moving will continue to move and an object at rest will remain at rest.
Explanation:
Match the atomic particles with their characteristics.
1. made of two protons and two neutrons
2. similar to an electron; positive charge
3. orbits nucleus; negative charge
4. bundle of energy; zero charge
5. found in nucleus; positive charge
6. very unstable; +, -, or zero charge
7. found in nucleus; zero charge
8. negative particle; negative charge
9. atomic energy converted to mass
Words to match to:
alpha
electron
positron
neutrino
proton
beta
gamma
neutron
meson
The atomic particles of which some are present in atom with their characteristics are given in serial order:Alpha 2.positron 3.electron 4.neutrino 5.proton 6.meson 7.neutron 8.beta 9.gamma.
What is an atom?An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.
The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.
Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.
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Which subatomic particles change the mass number? (select all that apply) Protons Neutrons Electrons
Answer:
protons and neutrons pretty sure
Explanation:
Please help me identify the element. The picture is blurry so..
Answer:
Explanation:
aluminium
CO2(g) + NH3(g) + H2O(l) → NH4HCO3(s) witch type of reaction plzz within 1 hour
Two different samples of solid iron are shiny, can be made into wire, and can rust when exposed to water. Why do the two samples have identical properties? A) They are composed of different types of atoms. B) They are composed of the same type of atoms. C) They have different masses. D) They have the same mass.
Which of the following determines if a substance is pure or a mixture? Select all that apply. a . Whether the mixture changes color when you apply a flame. b. Whether the matter is in a solid, liquid, or gas state. c. Whether the parts can be separated by physical or chemical methods. d. Whether you can see the parts without a magnifying device.
Answer:
free trees
Explanation:
235
92
U +
1
0
n →
90
36
Kr +
A
56
Ba + 3
1
0
n
Answer:
A= 143 B=146 C=56
Answer:
A: 143
B: 146
C: 56
Explanation: