Which of the following students best describes an element?
Answer:
I dont see anything.
Explanation:
But an element is a substance that is made only out of one atom.
Which example describes a chemical change
taking place?
A. water turning into steam
B. sugar dissolving in warm water
C. alcohol evaporating from a food while baking
D. nails rusting while sitting outside
MARKING BRAINLIEST!
Many processes occur in the digestive system. Which process is best classified as a physical change?
A. digestive enzymes breaking down proteins into smaller fragments
B. teeth grinding an almond into smaller pieces in the mouth
C. bacteria converting lactose into simple sugars in the intestines
D. saliva converting the starch molecules in crackers into simpler sugars
Answer:
Teeth gridning
Explanation:
BC YOUR GRINDING IT
A compound consists of 50.04% carbon, 5.59% hydrogen, and 44.37% oxygen. What is the empirical formula of this compound?
The empirical formula of the compound is C₃H₄O₂
From the question given above, the following data were obtained:
Carbon = 50.04%
Hydrogen = 5.59%
Oxygen = 44.37%
Empirical formula = ?Divide by their molar mass
C = 50.04 / 12 = 4.17
H = 5.59 / 1 = 5.59
O = 44.37 / 16 = 2.773
Divide by the smallest
C = 4.17 / 2.773 = 1.5
H = 5.59 / 2.773 = 2
O = 2.773 / 2.773 = 1
Multiply by 2 to express in whole number
C = 1.5 × 2 = 3
H = 2 × 2 = 4
O = 1 × 2 = 2
Therefore, the empirical formula of the compound is C₃H₄O₂
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Calculate the mass of Aluminum Bromide that can be made with 5.6 moles of Aluminum
The mass of Aluminum tri bromide that can be made with 5.6 moles of Aluminum is 1,492.90 grams.
What is the relation between mass & moles?Relation between the mass and moles of any substance will be calculated by using the below equation as:
n = W/M, where
W = given massM = molar massGiven chemical reaction is:
2Al + 3Br₂ → 2AlBr₃
From the stoichiometry of the reaction, it is clear that:
2 moles of Al = produces 2 moles of AlBr₃5.6 moles of Al = produces 2 moles of AlBr₃Now mass of AlBr₃ will be calculated by using the above equation as:
W = (5.6mol)(266.59g/mol) = 1,492.90g
Hence required mass of AlBr₃ is 1,492.90g.
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the density of a substance is 4.0g/cm3 if a sample of the substance has a volume of 25cm3 what is the mass
Answer:
100 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volume
From the question we have
mass = 4 × 25
We have the final answer as
100 gHope this helps you
How many moles are in 4.81x10^24 atoms of boron(B) ?
Show all of your work. Include units. round your answer to the correct number of significant figures.
Answer:
7.99 moles of boron
Explanation:
Given data:
Number of moles of B = ?
Number of atoms of B = 4.81 × 10²⁴ atom
Solution:
Avogadro number:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ atoms
4.81 × 10²⁴ atom × 1 mol / 6.022 × 10²³ atoms
0.799 × 10¹ mol
7.99 moles
Questlon 7 of 10
Which object will require the greatest amount of force to change its motion?
O A. A 72 kg object moving 25 m/s
O B. A 55 kg object moving 32 m/s
OC. A 75 kg object moving 22 m/s
O D. A 63 kg object moving 27 m/s
A 72 kg object moving 25 m/s will require the greatest amount of force
Further explanationGiven
mass of object and the velocity
Required
the greatest amount of force
Solution
Newton's 2nd law :
∑F = m. a
F = force, N
m = mass = kg
a = acceleration due to gravity, m / s²
Assuming the object is moving from rest (vo = 0) and the time needed to reach its velocity is the same (delta t = equal), it can be formulated:
[tex]\tt \Sum F=m.\dfrac{v_f-v_i}{\Delta t}\\\\F=m.\dfrac{v_f}{\Delta t}[/tex]
So the force on an object depends on the product of its mass and velocity
Or if we use the impulse and momentum formula
[tex]\tt F.\Delta t=m(v_f-v_i)\\\\F,\approx m.v_f[/tex]
So that we determine which is the greatest from the multiplication of mass and velocity will produce the greatest force as well
A 72 x 25 = 1800
B. 55 x 32 =1760
C. 75 x 22 = 1650
D.63 x 27 = 1701
Option A has the greatest force
The length of a year is equivalent to the time it takes for one.. (pls help I honestly forgot )
If the sun heated our atmosphere and the molecules began to s;read apart and rise but the atmosphere was to weak to keep them down , what would happen?
How long does it take for 87.5 % of each isotope to decay?
(The isotopes are below)
Krypton-73= 27 seconds
Krypton-74= 11.5 minutes
Krypton-76= 14.8 hours
Krypton-81= 2.1 x 10^5 years
Answer:
Kr-73 = 23.625 sec
Kr-74 = 10.0625 minutes (603.75 seconds)
Kr-76 = 12.95 hours (777 minutes)
Kr-81 = 1.8375 * 10^6 years
Explanation:
What you do is multiply each of those amounts by 7/8.
27 * 7/8 = 189/8 = 23.625
23/2 * 7/8 = 161/16 = 10.0625
74/5 * 7/8 = 518/40 = 259/20 = 12.95
210000 * 7/8 = 1470000/8 = 183750 = 1.8375 * 10^6
DOG SKELETAL SYSTEM BONES SKELETAL TISSUE BONE CELLS SMALLEST TO LARGEST
Answer:
tissue bone cells ,bones skeletal,dog skeletal system
Explanation:
You are required to identify the following substances using their properties Substance A. conducts electricity in both solid and liquid state. Substance
B. conducts electricity in solid state but its electrical conductivity in liquid state is unknown. Also it burns at a vey high temperature to give off carbon dioxide gas.
C. conducts electricity in liquid state but not in solid state Substance
D. does not conduct electricity in any state
You have to identify that; which substance is an ionic compound, which one is covalent compound , which one is a metal and which one is graphite.
Answer:
Explanation:
A. conducts electricity in both solid and liquid state.
Metal
B. conducts electricity in solid state but its electrical conductivity in liquid state is unknown. Also it burns at a vey high temperature to give off carbon dioxide gas.
Graphite
C. conducts electricity in liquid state but not in solid state
Ionic compound
D. does not conduct electricity in any state
Covalent compound
A metal is a substance that conducts both heat and electricity in solid and liquid state. They do this by the presence of free mobile electrons within their atomic space.
Graphite is a non - metal but it has free mobile electrons within its carbon frame work that allows of electrical conduction.
Ionic compounds are conductors only in molten state. In solid state, they do not conduct electricity and are called electrolytes in their liquid or molten form.
Covalent compounds do not ionize in solution and will not have ions which can conduct electric current.
1. A group of elements that includes the most active of the nonmetals is the
a. nitrogen group.
c. noble gases.
b. alkaline earths.
d. halogens.
Answer:
D. Halogens
Explanation:
All elements in these groups have 7 valence electrons, meaning their electronegativity is the highest among the elements.
A scoop of potassium oxide was placed in
55g of water which produced 67g of
potassium hydroxide. What mass of
potassium oxide was used?
A scoop of potassium oxide was placed in 55g of water which produced 67g of potassium hydroxide then mass of potassium oxide was used is 12g
Potassium oxide is used widely in the agricultural industry as a fertilizer
Here given data is
Potassium oxide was placed in 55g of water which produced 67g of potassium hydroxide
We have to calculate mass of potassium oxide was used =?
Then the reaction is
K₂O + H₂O → KOH
x + 55g = 67g
x = 67g - 55g
x = 12g
Therefore mass of potassium oxide was used is 12g
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How many grams are in 2.3 x 10^ -4 moles of calcium phosphate?
Answer:
Mass = 713.4 ×10⁻⁴ g
Explanation:
Given data:
Number of moles of calcium phosphate = 2.3×10⁻⁴ mol
Mass of calcium phosphate = ?
Solution:
Formula:
Number of moles = mass/molar mass
Molar mass of calcium phosphate is 310.18 g/mol
by putting values,
2.3×10⁻⁴ mol = mass / 310.18 g/mol
Mass = 2.3×10⁻⁴ mol × 310.18 g/mol
Mass = 713.4 ×10⁻⁴ g
Identify and describe the steps in the technology design process.
Answer:
Steps of the technological design process include: identify a problem, research the problem, generate possible solutions, select the best solution, create a model, test the model, refine and retest the model as needed, and communicate the final solution.
Explanation:
hope it helps, please mark brainliest
Steps of the technology design process include: identify a problem, research the problem, generate possible solutions, select the best solution, create a model, test the model, refine and retest the model as needed, and communicate the final solution.
What is technology?Technology is the application of knowledge for achieving practical goals in a reproducible way.The word technology can also mean the products resulting from such efforts, including both tangible tools such as utensils or machines, and intangible ones such as software. Technology plays a critical role in science, engineering, and everyday life.
Technological advancements have led to significant changes in society. The earliest known technology is the stone tool, used during prehistoric times, followed by the control of fire, which contributed to the growth of the human brain and the development of language during the Ice Age. The invention of the wheel in the Bronze Age allowed greater travel and the creation of more complex machines. More recent technological inventions, including the printing press, telephone, and the Internet, have lowered barriers to communication and ushered in the knowledge economy.
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Can someone solve this for me I'm confused.
Answer:
310.53 g of Cu.
Explanation:
The balanced equation for the reaction is given below:
CuSO₄ + Zn —> ZnSO₄ + Cu
Next, we shall determine the mass of CuSO₄ that reacted and the mass Cu produced from the balanced equation. This can be obtained as follow:
Molar mass of CuSO₄ = 63.5 + 32 + (16×4)
= 63.5 + 32 + 64
= 159.5 g/mol
Mass of CuSO₄ from the balanced equation = 1 × 159.5 = 159.5 g
Molar mass of Cu = 63.5 g/mol
Mass of Cu from the balanced equation = 1 × 63.5 = 63.5 g
Summary:
From the balanced equation above,
159.5 g of CuSO₄ reacted to produce 63.5 g of Cu.
Finally, we shall determine the mass of Cu produced by the reaction of 780 g of CuSO₄. This can be obtained as follow:
From the balanced equation above,
159.5 g of CuSO₄ reacted to produce 63.5 g of Cu.
Therefore, 780 g of CuSO₄ will react to produce = (780 × 63.5)/159.5 = 310.53 g of Cu.
Thus, 310.53 g of Cu were obtained from the reaction.
How might a collision between Neptune and Halley's Comet
affect Neptune's orbit?
Answer:
It will mess up the orbit around the sun
Explanation:
The impact of Halley's Comet with Neptune may force the asteroid to descend into Neptune's orbit, which may divert somewhat from its original path.
The collision of two heavenly bodies results in a powerful impact.
This collision might prevent Halley's Comet from continuing on its path and eventually colliding with Neptune.
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23. Select the evidence that Thomson used to conclude his findings.
(a) Electrons become excited with more energy and then release that energy as atomic
spectra.
(b) Performed a series of experiments using pressure, properties of gases, and properties
of compounds.
(c) Battery Passed a cathode ray between positively and negatively charged plates and observed the cathode ray attracting to the positively charged plate.
(d) Bombarded a thin layer of gold foil with alpha particles and detected that some alpha
particles passed through the gold foil while others deflected.i
Answer:
The answer is C
Explanation:
Thomson conducted many tests with cathode rays. Which led to his discovery of the electron.
what volume (in L) of a 3.95 M potassium chloride solution would be needed to make 325 mL of a 2.76 M solution by dilution
Explanation:
Moles of KCl in new solution = 0.325dm³ * (2.76mol/dm³) = 0.897mol.
Hence volume needed = 0.897mol / (3.95mol/dm³) = 0.227dm³ or 0.227L.
In the ground state, all of the atoms of Period 3 elements have the same
A) atomic number
B) number of oxidation states
C) number of occupied energy shells
D) atomic mass
Answer:
C) number of occupied energy shells
Explanation:
Atomic numbers of different elements must differ, as well as atomic masses. The number of oxidation states differs per atom as well.
Which list of terms best describes the formation of sedimentary rocks
Explanation:
Weathering - erosion - transportation - deposition
Sedimentary rocks are rocks that are formed from pre-existing rocks. The agents of denudation plays very important roles during the formation these rock types.
Existing rock bodies are broken down in to tiny fragments. These fragments are carried by erosion and transported. In the basin they are deposited as layers. Compaction, lithification and cementation occurs with burial. This will then lead to the formation of sedimentary rocks.3. What mass of copper could be deposited from a copper(II) Sulphate solution using a current of 5.0 A over 100 seconds? ( F =96,500C,Charge of Cu in CuSO4 = +2)
Mass of copper : 0.165 g
Further explanationGiven
5.0 A over 100 seconds
Required
Mass of copper
Solution
Faraday's law:
The mass of the substance formed at each electrode is proportional to the electric current flowing in the electrolysis
[tex]\tt W=\dfrac{e.i.t}{96500}[/tex]
e = Ar / valence = eqivalent weight
i = current
t = time
W = weight
CuSO₄ ----> Cu²⁺ + SO₄²⁻
Cu ----> Cu²⁺ + 2e
e = Ar/2
= 63,5/2 = 31,75
[tex]\tt W=\dfrac{31.75\times 5\times 100}{96500}=0.165~g[/tex]
One can find the pH of a substance by using ___.
A. a conductivity tester
B. a thermometer
C. plain paper indicator
D. litmus paper indicator
Explanation:
C. Plain paper indicator.
Litmus paper indcator can only tell you if the solution is acidic/neutral/alkaline, but not to what extent.
What mass of gold (Au) contains the same number of atoms as 2.61 g of aluminum (Al)?
Answer:
19.11g
Explanation:
mole = mass ÷ molar mass
mole = 2.61 ÷ 27
mole = 0.097mol
Number of atoms in 2.61g of Aluminum = 6.022 × 10^23 × 0.097
= 0.584 × 10^23
= 5.84 × 10^22atoms
To get the same number of atoms for Gold (Au), we multiply the atomic mass of Au by 0.097mol
Atomic mass of Au = 197g/mol
mass = mole × molar mass
mass = 0.097 × 197
mass = 19.109g
mass = 19.11g
How many grams of carbon are required to produce 0.460 moles of SiC?
SiO2 + C → SiC + CO
Answer:
Sick Core corona +iep =Qurintine
The model below shows a part of a human body's muscular system.
Muscles are organs that make movement possible. Which organ system is responsible for controlling muscular movement?
A. Endocrine system
B. Skeletal system
C. Nervous system
D. Digestive system
Answer:
you must go to jones im doing the same test
Explanation:
Dan wants to test the effects of different amounts of antibiotic on bacteria. While setting up his experiment he makes sure to use the same type of antibiotic, the same type of bacteria, and the same type of incubator for each trial. Which phrase below best describes this part of the experiment?
Answer:
C
Explanation:
A. analyzing results
B. collecting data
C. choosing controlled variables
D. making a prediction
The correct answer would be choosing controlled variables.
The controlled variables are factors that are kept constant among the different groups of subjects during the course of an experiment so as to be able to isolate the effects of a single factor - the independent variable.
There are basically 3 types of variables in a scientific experiment;
1. The independent variable
2. The dependent variable
3. The controlled variable
The independent variables are the variables whose effects are to be determined in the course of experiments. The dependent variables are the variables that are actually measured during the course of experiments and whose values vary along with that of the independent variables. The controlled variables are other variables required for the experiment but which must be kept constant among subjects in order to be able to isolate the effects of the independent variable.
The correct option is C.
what is the average atomic mass of einsteinium? what are its common isotopes?
Answer:
Boom
Explanation:
The bomb is big and it goes boom and it also creates nuclear fragments everywhere