Answer:
Explanation:
Combustion can be defined as the burning of a compound in the presence of oxygen to produce carbon dioxide and water. Because it involves the release of heat (energy), it is referred to as an exothermic reaction.
Fuel is an organic compound and it's combustion will also go through the process above and also releases heat (exothermic reaction) into the atmosphere after burning. However, same can be said about forest fire also; as the forest is made up of plants (whose major constituents are organic also). The forest fire can also be termed as combustion because it burns in the presence of oxygen, releasing heat (energy) into the atmosphere (which also makes it an exothermic reaction).
A forest fire models the energy flow of fuel combustion by:
Reacting with oxygen to create heatCombustion is the chemical process whereby there is a redox reaction that causes burning and produces smoke in the form of gas.
For combustion to occur, the following processes must occur:
There must be the presence of an oxidantThere has to be a reaction between the oxidant and heat.The end product must be carbon dioxide and water.As a result of this, a forest fire models the energy flow of fuel combustion by making use of a reactant like wood to create combustion.
Because this process expels energy, then it is known as an exothermic reaction.
Therefore, forest fire occurs:
In the presence of:oxygenBy expelling heat By producing carbon dioxide and water.Read more here:
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2. The model on the right looks bumpy, but when you break a large salt crystal in two, the edges of the split often look straight and feel smooth. Is there a problem with the model?
Answer:
Maybe the sizes are too big which means that they need to be smaller because the more compact they are the more smooth and straight they will be because when they are too big it is easier to break them which would lead to a bumpy surface.
Explanation:
I don't know :)
he Solids model formed by atoms as solid spheres for macroscopic measurements, the model has no problems, because the atoms are extremely small
Dalton's atomic model was the first scientifically based model formulated in 1808, it consists of atoms with spheres that cannot be divided and solids are formed by contact between the spheres and chemical compounds are formed by joining atoms of two or more elements, this model is used to approximate solids such as solid spheres there are today.
The size of these spheres (atoms) is very small, nowadays it is known that it is of the order of 10⁻⁹ m, therefore, having a macroscopic crystal more than 10⁻⁶ m in length, it is impossible to measure fluctuations in the sizes of the spheres, since there are 10⁹ spheres in this volume, therefore it is not possible to measure the fluctuations with instruments,
To be able to measure this fluctuation, very small samples and very high resolution transmission microscopes are needed.
In conclusion, the model of the atom as solid spheres for macroscopic measurements, the model has no problems.
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HELP ASAP! WILL GIVE BRAINLY!! Match each of the unknown ions to its appropriate description. 1.B+ 2.A− 3.D^2+ 4.C^2− a.A nonmetal that gained one electron b.A metal that lost one electron c.A nonmetal that gained two electrons d.A metal that lost two electrons
1B.a metal that lost one electron
4C a non metal that gained two electrons
Define compressibility
Answer:
Compressibility means: being able to basically squish something easier. Like water, water can be reduced in volume or size under pressure When that water expands, it turns into a gas.
Explanation:
Which model is most similar to that of Aristarchus? The solar system shows the planets in their orbits around the sun in this order: Mercury, Venus, Earth with Moon, Mars, Jupiter, Saturn. Fixed stars are around the outside of the orbit of Saturn. The solar system shows the planets in their orbits around Earth in this order: Moon, Mercury, Venus, Sun, Mars, Jupiter, Saturn, Fixed stars. The solar system shows the sun and planets in their orbits around Earth in this order: Moon, Mercury, Venus, Sun, Mars, Jupiter, Saturn.
Answer:
It’s the first model
Explanation:
Answer:
The solar system shows the planets in their orbits around the sun in this order: Mercury, Venus, Earth, with Moon, Mars, Jupiter, Saturn. First choice
Explanation:
Just had the question.
A student drew a diagram of the quantum model of an atom, as shown. A small circle is shown. Six light gray spheres and six dark gray spheres are shown inside the circle. On the outer side of the circle is a diffused shaded circular region. This diffused shaded circular region has two distinct bands of dark gray shading in it. Which of the following explains if the student's diagram is correct or incorrect? The diagram is incorrect because electrons follow orbital rings around the nucleus. The diagram is incorrect because there is only a single type of particle at the center of the atom. The diagram is correct because electrons are present in a negatively charged cloud outside the nucleus. The diagram is correct because all electrons can be accommodated in two electron clouds around the nucleus.
Answer:
The diagram is incorrect because there is only a single type of particle at the center of the atom.
Explanation:
The small circle at the centre of the sphere which contains six light gray spheres and six dark gray spheres represents the nucleus of the atom which is found at the centre of the atom.
The nucleus contains only one type of particle which is the proton. Hence the representation of two particles at the centre of the circle makes the model incorrect.
Answer:
D- The diagram is correct because all electrons can be accommodated in two electron clouds around the nucleus.
Explanation:
This is the correct answer because i just took the pre-quiz and tried B and A and they were both incorrect and C just doesnt make any sense so yeah hope it helped :)
Suppose an astronomer discovers a large, spherical-shaped body orbiting the Sun. The body is composed mostly of rock, and there are no other bodies sharing its orbit.
Answer:
The answer is "Comet".
Explanation:
The comets were interstellar frozen gas of snowballs, stone, and debris orbiting the sun, which are also the size of average towns while frozen. As even the orbit of the comet passes near the sun, it warms up and spreads dust and gas into a big floating head greater than most stars.
It is very important because they are primitive items left out from the galaxy creation. They were one of the first solid materials throughout the solar nebula, its collapsing interstellar-like cloud of dust and gas, which established the heat and planets.Answer: A Planet
Explanation:
The International Astronomical Union defines a planet as a spherical object that orbits a star. Planets clear the neighborhood around their orbits (i.e., no other bodies share their orbits).
Which of these are properties of solids? Select all that apply.
a. Takes the shape of its container.
b. Molecules vibrate in a fixed position.
c. Strong attraction between molecules.
d. No definite volume.
PLEASE HELP
Answer:
B.
Explanation:
Solids vibrate in a fixed position because they keep their shape. Liquids take the shape of their container, so A cannot be the answer. Solids do have a definite volume, so D is not your answer.
What is the scientific method and what the second step of the scientific ? If you answer the question right you will get a 5 star and a brainly
Answer:
a method of procedure that has characterized natural science since the 17th century, consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses.The basic steps of the scientific method are: 1) make an observation that describes a problem, 2) create a hypothesis, 3) test the hypothesis, and 4) draw conclusions and refine the hypothesis.
Explanation:
the scienticif Method and the second step of the scientific
Select True or False.
Social Security is normally paid out in the lump payment upon  retirement
Answer:
TRUE MY DOOD
Explanation:
How many meters are present in the 12.45 miles? Please show your work, and report your answer with the correct number of significant figures and appropriate units.
Explanation:
We know that,
1 mile = 1609.34 m
We need to find how many meters are present in the 12.45 miles. To find it use unitary method as follows :
12.45 mile = 1609.34 × 12.45
12.45 mile=20036.283 meters
or
[tex]12.45\ mile=2.0036\times 10^4\ m[/tex]
Hence, this is the required solution.
Q1: What problem did the development of the metric system solve? Write your answer below!
Answer:
It solved the issue of depending on too many base units
Explanation:
It was first adopted by the French government. Metric system was developed by Gabriel Mouton of Lyons, he is called the founding father of the metric system. He proposed the decimal system of measurement that was refined by the scientists.
The metric system is simple for making measurements, you just need to know few metric units. There are seven base units in this system of measurement while there are twenty base units in inch-pound system of measurement. Metric system is easier to remember. The metric system follows the decimal number system and it decreases and increases in size by 10.
It has been adopted by all the countries of the world except Myanmar and US.
A scientist conducted research and plotted his results in the histogram shown below. Which of the following is the best measure of the center of the data?
Median
Mode
Mean
They are all appropriate
Answer: Mean
Explanation:
The histogram in the given picture gives slightly bell shaped curve.
That means the data is symmetric and follows normal distribution.
Out of Mean, Median and mode , Mean is the best measure of the center of the data when data distribution is continuous and symmetrical.
We choose median if data has extreme values where as mode is considered as least measure of tendency and it used in nominal data.
Hence, the correct option is "Mean".
Which of the following numbers has three significant figures?
all of the choices
1000 yards
1014 miles
101 feet
Answer:
The correct answer is 101 feet.
Explanation:
To solve this problem, we need to remember the rules of significant figures. Any digit that is not zero is significant, and any zero is significant if it is between two non-zero digits or a trailing zero after the decimal point. Now, let's apply these rules to the options that are given:
1000 yards - Since the zeros are not after the decimal point or between two other digits, they are not significant. This means the only significant digit is 1, so there is only 1 significant digit.
1014 miles - All three of the non-zero digits are significant, and the 0 is significant in this case because it is between two other significant digits. Therefore, this number has 4 significant digits.
101 feet - The two 1's are significant because they are non-zero digits, and the zero is also significant because it is between the two 1's. Therefore, this number has 3 significant digits.
Thus, your answer is 101 feet.
Hope this helps!
Several scientists from different countries are asked to examine the results of an experiment before a journal will print it.
Which term best describes this step of the investigative process?
A)question
B)communication of results
C)peer review
D)experiment control
Answer:
C)peer review
Explanation:
Peer review involves the evaluation of scientific research work by other professionals working in the same field. It is one of the stages a manuscript passes through before it is published in any reputable journal.
Peer review is important because it ensures that only high quality and original scientific research is published for the consumption of other professionals in the same field.
The Average Speed of the orbiting space shuttle is
17500 miles/hour. What is the speed in kilometers/
second?
Explanation:
It is given that, the Average Speed of the orbiting space shuttle is 17500 miles/hour.
We need to convert the speed in kilometers/ second
We know that,
1 mile = 1.609 km
or
1 km = 0.621 miles
1 hour = 3600 seconds
[tex]17500\ \dfrac{\text{miles}}{\text{hour}}=17500\ \dfrac{\text{miles}}{\text{h}}\times \dfrac{1\ h}{3600\ s}\\\\=17500\times \dfrac{\text{miles}}{3600\ s}[/tex]
Now cancel the miles in numerator.
[tex]17500\times \dfrac{\text{miles}}{3600\ s}=17500\times \dfrac{\text{miles}}{3600\ s}\times \dfrac{1.609\ km}{1\ \text{miles}}\\\\=17500\times \dfrac{1.609}{3600}\ km/s\\\\=7.82\ km/s[/tex]
So, 17500 miles/hour is equal to 7.82 km/s.
a certain gas occupies 5 dm³ at 24 °C and 15 cm Hg. Calculate the pressure of the gas if the volume is halved and the temperature is raised to 200°C.
Explanation:
(P1V1)/T1=(P2V2)/T2
(15X5)/297=(p2x2.5)/473
p2=47.78cmHg
You have a container filled with 24 moles of neutral lithium. How much negative electric charge is contained in the electrons of all the lithium atoms in the container
Answer:
There are 6.94x10⁶ C of the negative electric charge contained in the electrons of all the lithium atoms in the container.
Explanation:
We have 3 moles of electrons (e⁻) in 1 mol of Li, so the quantity of negative electric charge is:
[tex] \frac{3 moles \thinspace e^{-}}{1 mol Li}*24 moles Li*\frac{6.022 \cdot 10^{23} e^{-}}{1 mol \thinspace e^{-}}*\frac{1.60 \cdot 10^{-19} C}{1 e^{-}} = 6.94 \cdot 10^{6} C [/tex]
Therefore, there are 6.94x10⁶ C of the negative electric charge contained in the electrons of all the lithium atoms in the container.
I hope it helps you!
A participant took 5.2 hours to complete a marathon. How many minutes did the participant take to complete the marathon?
Answer:
312 minutes
Explanation:
because 1 hour = 60 minutes this is the example they give you so then you do the math from there
Which of the following is an oxidation-reduction reaction? KOH + HNO3 → H2O + KNO3 CaCl2 + Na2SO4 → CaSO4 + 2NaCl AgNO3 + NaCl → AgCl + NaNO3 Al2(SO4) 3 + 6KOH → 2Al(OH)3 + 3K2SO4 N2 + O2 → 2NO
Answer:
N2 + O2 → 2NO is an oxidation-reduction reaction.
Explanation:
An oxidation-reduction reaction (also know as Redox reaction) is a type of chemical reaction that involves a transfer of electrons between two species. It occurs when the oxidation number of a molecule, atom, or ion changes by gaining or losing an electron.
We will consider the equations one after the other.
KOH + HNO3 → H2O + KNO3Oxidation numbers of the individual element on the reactant side:
KOH : K = +1, O = -2, H = +1
HNO3 : H = +1, N = +5, O = -2
Oxidation numbers of the individual element on the product side:
H2O: H = +1, O = -2
KNO3: K = +1, N = +5, O = -2
There is no change in the oxidation numbers, hence, it is not an oxidation-reduction reaction.
CaCl2 + Na2SO4 → CaSO4 + 2NaClOxidation numbers of the individual element on the reactant side:
CaCl2 : Ca = +2, Cl = -1
Na2SO4: Na = +1, S = +6, O = -2
Oxidation numbers of the individual element on the product side:
CaSO4: Ca = +2, S = +6, O = -2
NaCl: Na = +1, Cl = -1
There is no change in the oxidation numbers, hence, it is not an oxidation-reduction reaction.
AgNO3 + NaCl → AgCl + NaNO3Oxidation numbers of the individual element on the reactant side:
AgNO3: Ag = +1, N = +5, O = -2
NaCl: Na = +1, Cl = -1
Oxidation numbers of the individual element on the product side:
AgCl: Ag = +1, Cl = -1
NaNO3: Na: +1, N = +5, O = -2
There is no change in the oxidation numbers, hence, it is not an oxidation-reduction reaction.
Al2(SO4) 3 + 6KOH → 2Al(OH)3 + 3K2SO4Oxidation numbers of the individual element on the reactant side:
Al2(SO4)3: Al =+3, S = +6, O = -2
KOH: K = +1, O = -2, H = +1
Oxidation numbers of the individual element on the product side:
Al(OH)3: Al =+3, O = -2, H = +1
K2SO4: K = +1, S = +6, O = -2
There is no change in the oxidation numbers, hence, it is not an oxidation-reduction reaction.
N2 + O2 → 2NOOxidation numbers of the individual element on the reactant side:
N2: N = 0
O2: O = 0
Oxidation numbers of the individual element on the product side:
NO: N = +2, O = -2
There are changes in the oxidation numbers, hence, it is an oxidation-reduction reaction.
The following is an oxidation-reduction reaction - N2 + O2 → 2NO
Oxidation numbers represent the potential charge of an atom in its ionic state. If the oxidation number decreases in a reaction, it is reduced. If an atom's oxidation number increases, it is oxidized.
CaCl2 + Na2SO4 → CaSO4 + 2NaCl is a double displacement reaction KOH + HNO3 → H2O + KNO3 is acid-base neutralization reaction AgNO3 + NaCl → AgCl + NaNO3 is double displacement reaction Al2(SO4) 3 + 6KOH → 2Al(OH)3 + 3K2SO4 is double displacement reactionAll three reaction mention above is not oxidation-reduction reaction as each atom has the same oxidation number in these reactions. N2 + O2 → 2NO is oxidation-reduction reaction.= > Oxidation state of N in the reactant is 0
=> Oxidation state of N in the product is +2
So, N is oxidized
=> Oxidation state of O in the reactant is 0
=> Oxidation state of O in the product is -2
So, O is reduced
Thus, the following is an oxidation-reduction reaction - N2 + O2 → 2NO
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Why is it important to read over the SDS sheet before you do a lab?
Answer:
so you know what to do and you know the rules
Explanation:
HELPPPPP ME ASAP I'll give you a thanks and mark you as brainliest and give u points
Suppose that the clay balls model the growth of a planetesimal at various stages during its accretion. Choose the planetesimal that is most likely to pull in debris particle A.
Answer: 2nd one
Explanation:
PLATO
Which part of Earth most likely has the highest albedo value?
Answer:
Sea ice
Explanation:
Sea ice has a much higher albedo compared to other Earth surfaces
An ideal gas with γ = 1.67 has an initial temperature of 0°C, initial volume of 10.0 liters, and initial pressure of 1.00 atm. Then the gas is expanded adiabatically to a volume of 10.4 liters. What is the new temperature? (1 point)
Answer: T = 9.74°C
Explanation: An ideal gas in a quasi-static adiabatic process follows the equation: [tex]pV^{\gamma} = constant[/tex].
So:
[tex]1.10^{1.67} = constant[/tex]
constant = 46.7735
Adiabatic conditions can be written as:
[tex]TV^{\gamma-1}=constant[/tex]
Then, new temperature is
[tex]T.(10.4)^{1.67-1}=46.7735[/tex]
[tex]T.(10.4)^{0.67}=46.7735[/tex]
[tex]T = \frac{46.7735}{4.802}[/tex]
T = 9.74°C
The new temperature is 9.74°C.
Hii, i’m having a bit of trouble on this and would appreciate help. thank you!
Answer:
Option A. 231 90Th
Explanation:
Please see attached photo for explanation
what is 5800 in scientific notation?
Answer:
5.8 x 10³
Explanation:
How can you determine a chemical property of a substance
Answer:When chemists study chemical substances, they examine two types of properties: chemical properties and physical properties. Some physical properties are extensive properties, properties that depend on the amount of matter present. Mass and volume are extensive properties.
Explanation:
Answer:
to observe the change in the color of the substance during a reaction
Explanation:
______Reflects how closely packed the particles of matter are
Answer:
Density
Explanation:
A piece of metal ore weighs 9.00 g. When a student places it into a graduated cylinder containing water, the liquid level rises from 21.25 mL to 26.47 mL. What is the density of the ore
Answer:
1.72 g/ml
Explanation:
If our aim is to determine the density of the metal ore, then;
Mass of the metal ore= 9.00 g
Volume of the ore= volume of water displaced = 26.47 - 21.25 = 5.22 ml
Density of the ore= 9.00 g/5.22 mk
Density of the ore= 1.72 g/ml
I need help please, will mark you the brainliest.
Explanation:
The orbital diagram of an electron with eight electron is attached. Since the 2p orbitals are filled using the maximum space available instead of pairing the electrons, this is in accord with Hund's rule.
When filling orbitals, you should put one electron in each box. After all of the boxes in the orbital have one electron in each, you can then put the second electron into each of the boxes.
Separate a mixture of sand, common salt, copper pieces and iron fillings. Also measure the amount of common salt in the mixture. Write the steps and the procedure of separation. Also what safety measures you will take during the experiment.
Answer:
Explanation:
This question seeks to test the knowledge of separation techniques.
From the narration in the question, the first separation to be done is the removal of Iron fillings by the use of magnet (magnetic separation). Since Iron is magnetic, the iron fillings will be attracted by the magnet hence removing the iron fillings from the mixture.
The second constituent to be removed will be the copper pieces by the use of a sieve (sieving). Copper pieces have relatively larger sizes than sand and common salt, hence a sieve (which separates particles based on size) can be used to remove the copper pieces from the mixture.
What will be left in the mixture after the processes above will be salt and water. This mixture will have to be dissolved in water; the salt will dissolve in water while the sand will not. After which, filtration will be done to remove the sand which will be collected on the filter paper as filtride and the salt solution will pass through the filter paper as filtrate.
The salt solution can then be evaporated to dryness to retrieve the solid salt from the solution.
The amount of salt in the mixture can then be measured using a weighing balance.
Some of safety measures to be taken during the course of this experiment includes performing the experiment in an airtight and controlled environment. Lab coat and hand gloves should be worn during the course of the experiment. The evaporation to dryness should not be done close to an inflammable material/substance