The scientists who have contributed to our current body of knowledge were
from what part of the world?
A. All areas of the world
B. Mostly Europe
C. Mostly the Middle East
D. Only the United States
SEMIT
Answer:
A.
Explanation:
Well, Nicola Tesla was from Croatia.
Albert Einstein was from Germany.
Thomas Edison was from the U.S.
So I think all over.
Which of the following is an example of a testable scientific hypothesis?
A.
Why do plants grow better in the Sun than in the shade?
B.
Gorillas are happier in the wild than they are in the zoo.
C.
Roses grow faster in the Sun than in the shade.
Mr. Auric Goldfinger, criminal mastermind, intends to smuggle several tons of gold across international borders by disguising it as lumps of iron ore. He commands his engineer minions to form the gold into little spheres with a diameter of exactly
8 cm and paint them black.
However, his chief engineer points out that customs officials will surely notice the unusual weight of the "iron ore" if the balls are made of solid gold (density
). She suggests forming the gold into hollow balls instead , so that the fake "iron ore" has the same density as real iron ore
One of the balls of fake "iron ore," sliced in half.
Calculate the required thickness of the walls of each hollow lump of "iron ore." Be sure your answer has a unit symbol, if necessary, and round it to 2
significant digits.
The thickness of the walls of each hollow lump of iron ore is: 0.295cm. This is determined using the knowledge of the Volume of a Hollow Sphere.
What is the Volume of a Hollow Sphere?
The formula for the Volume of a Hollow Sphere is give as:
Volume of a Hollow = 4/3 R³ – 4/3 r³
Step 1 - Find the apparent volume of 8cm diameter sphere including the wall the the hollow inside
V = 4/3 r³
V = (4/3) (8)³
V = (4/3) * (22/7) * 512
V = 2145.52cm³
Step 2 - Determine the mass of Gold required for the sphere to achieve the density of iron ore if the apparent volume is as given in Step 1 above.
Recall that Mass = Density * Volume
Mass = 5.15 * 2145.52
Mass = 11049.45
Step 3 - Find volume of gold based on mass calculated in Step 2 above
Recall that :
Volume = Mass/Density
Thus,
V = 11049.4/19.3
Thus, Volume = 572.51cm³
Step 4 - Find the width of the wall of a hollow sphere for the volume realized in step 3
Recall the initial formula:
Volume of a Hollow = 4/3 R³ – 4/3 r³
Thus, 572.51 = (4/3) (8³ - (8 - t)³)
572.51 = (4/3) *(22.7) *(8³ - (8 - t)³)
572.51 = (88/21) *(8³ - (8 - t)³)
Multiply both sides by 21 and we have
88 (512 - (8 - t)³) = 12,022.71
Simplify further
(8 - t)³ = 357.38
t = 0.9035cm
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What does a particular point on a line of a phase diagram represent?
A. The pressure created by the kinetic energy of molecules at a
particular temperature
B. The maximum temperature a substance can exist at without
bonds breaking
OC. The melting point or boiling point of a substance at a specific
pressure
OD. The conditions in which temperature and pressure have equal
effects on a substance
Answer:
The point at which the lines intersect represents the triple point.
Fast food and juice boxes are example of which of these?
group of answer choices
habitat destruction
air pollution
water pollution
overpackaging
i need a answer within 20 mins i will give 30 points
Answer:
habitat destruction I think
Explanation:
A student placed equal-sized potato cubes in two different beakers containing either distilled (pure) water or a concentrated sugar solution. The experiment is shown in Figure 2.
Explain
what would happen to the mass of the potato cube after being placed in distilled (pure) water
Please help me
When the potato is put into the distilled water, it will absorb the water. The water is trying to dilute the salt inside the potato.
What is the meaning of concentrated?
The concentration of a solution is a measure of the amount of solute that has been dissolved in a given amount of solvent or solution.
When the potato is put into the distilled water, it will absorb the water. The water is trying to dilute the salt inside the potato.
Since potatoes already contain sugar, less water will diffuse out of the potato placed in sugar water. The slice placed in water will be rigid since it will absorb water.
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Identify the reaction type for each unrelated, radical reaction as either initiation, propagation, or termination. Reaction A. A chlorine chlorine bond splits into two chlorine radicals. What type of reaction is reaction A
A is the initial reaction when a chlorine bond splits into two chlorine radicals.
What are radicals?In chemistry, a radical is an atom, molecule, or ion that has an unpaired valence electron.
The question is based on Radical Chain Reaction. And these reactions have three different phases: Initiation, Propagation and Termination.
Reaction A- Initiation
Reaction B- Termination
Reaction C- propagation
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PLS HELP
4. T or F X-rays, ultraviolet light, and gamma rays all can travel through interplanetary space, so they are examples of waves.
5. What happens to the amplitude of water waves as you get farther from the disturbance that caused them? Why?
4. True
5. The amplitude of the ripples decreases as the circumference of the circle increases.
What is a wave?A wave is a disturbance that moves energy from one place to another.
Radio waves, gamma-rays, visible light, and all the other parts of the electromagnetic spectrum are electromagnetic radiation. Electromagnetic radiation can be described in terms of a stream of mass-less particles, called photons, each travelling in a wave-like pattern at the speed of light. Hence, the statement is true.
As the disturbance moves outwards the energy it carries is spread over a larger and larger region called the wavefront. For example, the ripples in the water lie in a circle with an ever-increasing circumference. The amplitude of the ripples decreases as the circumference of the circle increases.
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An intravenous solution is noted as having a concentration of glucose equal to 0.312 M. What volume of solution (in mL) is needed to deliver 0.078 moles of glucose to the patient?
The volume of the solution in mL needed to deliver 0.078 moles of glucose to the patient is 250mL.
How to calculate volume?The volume of a solution can be calculated by using the following formula:
Molarity = n/V
Where;
n = number of molesV = volumeAccording to this question, an intravenous solution is noted as having a concentration of glucose equal to 0.312 M. The volume that will be needed is as follows:
volume = 0.078 moles ÷ 0.312M
volume = 0.25L = 250mL
Therefore, the volume of the solution in mL needed to deliver 0.078 moles of glucose to the patient is 250mL.
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What is the answer to this question? I need help!!
Answer:
[tex]\fbox {C}[/tex]
Explanation:
By repeating the experiment with new amounts of each reactant, this conflict can be resolved as we can see the effect of a reactant on the final amount of product formed.
The 9.6 g object displaced
3.2 mL of water.
What is its density in g/mL?
density=[?] g/mL
Answer: 3
Explanation:
Density is mass/volume divide the mass 9.6 by the volume of 3.2
[tex]\frac{9.6}{3.2} =3[/tex]
The density of the object displaced in water is equal to 3 g/ml.
What is the density?The density of a substance can be described as the substance's mass per unit of its volume. The symbol is generally used to represent density ρ and the letter D can be used.
The mathematical formula of the density of a material can be represented as shown below:
Density = Mass/volume
ρ = m/V
The density of a material varies with pressure as well as temperature. There is a small variation in the density of the solids and liquids but much larger for gases. Increasing the pressure of the substance decreases the volume and thus increases its density.
As the object displaced water of volume of 3.2 ml.
Therefore, the volume of the object, V = 3.2 ml
The mass of the object, m = 9.6 g
The density of the object placed in water can be calculated as:
Density of object = 9.6/3.2 = 3 g/ml
Therefore, the density of the object is 3 g/ml.
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Please answer step by step.
3 moles of NaOH reacts with 1 mole of phosphoric acid.
What is the moles ratio of the NaOH and Phosphoric acid reaction?The moles ratio of the reaction between NaOH and Phosphoric acid is given by the equation of the reaction below:
[tex]3\:NaOH + H_{3}PO_{4} \rightarrow Na_{3}PO_{4} + 3\:H_{2}O \\ [/tex]
Based on the equation of the reaction, 3 moles of NaOH reacts with 1 mole of phosphoric acid.
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Ammonia gas occupies a volume of 450. mL at a pressure of 720. mm Hg. What volume will it occupy at standard pressure?
Show your work Please!!!!
A sealed container can hold
0.325 L of gas at 1.00 atm
and 293 K. How many moles of gas
can the container hold?
0.216 moles of gas can the container hold if a sealed container can hold 0.325 L of gas at 1.00 atm and 293 K.
What is an ideal gas equation?The ideal gas law (PV = nRT) relates the macroscopic properties of ideal gases. An ideal gas is a gas in which the particles (a) do not attract or repel one another and (b) take up no space (have no volume).
PV=nRT, where n is the moles and R is the gas constant. Then divide the given mass by the number of moles to get molar mass.
Given data:
R = gas constant = 0.08206 L.atm / mol K
T = temperature, Kelvin
V=5 L
P = 1.05 atm
T = 296 K
Putting value in the given equation:
[tex]\frac{PV}{RT}=n[/tex]
[tex]n= \frac{1.05 atm\; X \;5 L}{ 0.08206 L.atm / mol K X 296 K}[/tex]
Moles = 0.216 moles
Hence, 0.216 moles of gas can the container hold if a sealed container can hold 0.325 L of gas at 1.00 atm and 293 K.
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Answer:
0.014
Explanation:
Use the formula PV=nRT; there are calculators for it online as well.
the screenshts below
Answer:
yes so for example one
Explanation:
yeah so
Given the balanced equation representing a
reaction:
2NO+ O₂ → 2NO₂ + energy
1. The mole ratio of NO to NO₂ is
(1) 1 to 1
(2) 2 to 1
(3) 3 to 2
(4) 5 to 2
Answer: it would be a 1 to 1 ratio
Explanation: originally it would be 2 to 2 but you have to reduce
. What is the relationship between the speed of impact and the dropping height?
The relation between the speed of impact and the dropping height is
[tex]\rm h =\dfrac{1}{2g}v^2[/tex]
What is Speed of Impact ?It is defined as the speed of an object when it falls from a height and makes an impact with the ground or any other object.
As the object is falling from the height , its velocity will be continuously changing
Assuming it has no initial velocity , u = 0
let the final velocity is [tex]\rm v_f[/tex] = [tex]\rm \sqrt {2gh}[/tex]
the potential energy at the height h as mgh
the kinetic energy when it reaches the bottom as [tex]\rm \dfrac{1}{2}mv^2[/tex]
As the energy is always conserved
[tex]\rm mgh = \dfrac{1}{2}mv^2[/tex]
[tex]\rm h =\dfrac{1}{2g}v^2[/tex]
This is the relation between the speed of impact and the dropping height.
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what are the 3 common gases that give off reactions?
The 3 common gases that give off reactions are Hydrogen sulfide, Carbon monoxide, Nitrogen oxides.
What are off reactions
Off reactions are defined as chemical reactions that occurs when something burns or during combustion of materials which gives off energy.
Some gases that give off reaction are:
Hydrogen sulfideCarbon monoxideNitrogen oxidesNote that these gases are mostly poisonous.
Therefore, the 3 common gases that give off reactions are Hydrogen sulfide, Carbon monoxide, Nitrogen oxides.
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Ethanoic acid reacts with ethanol to form an ester and water. How many moles of ethanoic acid are required to produce 0.5 mol of the ester? (A) 0.05 (B) 0.5 (C) 1 (D) 2
0.5 moles of ethanoic acid are required to produce 0.5 mol of the ester , Option B is the right answer.
What is esterification reaction ?The reaction in which a carboxylic acid combine with an alcohol to form ester and water is called esterification reaction.
It is given in the question that
Ethanoic acid reacts with ethanol to form an ester and water
C₂H₅OH + CH₃COOH → CH₃COOH + H₂O
The moles of ethanoic acid required to produce 0.5 mole of ester.
In the following reaction it can be seen that the mole fraction of ethanoic acid to ester is 1: 1
Therefore 0.5 mole of ethanoic acid will be required to produce 0.5 mol of ester.
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A solution is 0.225M Na2SO4. What is the molarity of the sodium ion in solution
The molarity of the sodium ion in the solution is 0.450 M.
How do we determine the molarity of sodium ions in a solution?The molarity of the sodium ion in a solution can be determined by the dissociation of the given solution Na2SO4(sodium sulfate).
The dissociation of Na2SO4 is computed as follows:
1 mole of Na2SO4 dissociates to give 2 moles of sodium cations and 1 mole of sulfate anion.i.e.
[tex]\mathbf{Na_2SO_4 \to 2Na^{+} + SO_4^{2-}}[/tex]
The molarity for sodium-ion [Na+] is:
= 2 × 0.225 M
= 0.450 M
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For the function F(x) = 1, which of these could be a value of F(x) when x is
close to zero?
Answer:
A. -10,000
Explanation:
When x approaches zero, the graph tells us that F(x) either becomes extremely large or extremely small. The best answer is therefore A: -10,000. Best, because we aren't given the exact value of x, but clearly the other results require that x be greater than 1 or less than -1, which is far from zero.
Give some examples of what are sand good for explaining is involved!
Explanation:
The definition of a god is an image, person or thing that is worshiped, honored or believed to be all-powerful or the creator and ruler of the universe. An example of a god is Ganesha, a Hindu diety.
what is the wavelength of a microwave with a frequency of 2450 mhz
Answer:
See below
Explanation:
The way to calculate this
speed of light = wavelength * frequency
3 x 10 ^8 m/s = wavelength * 2450000000 Hz
wavelength = .12245 meters
= 1.2245 x 10^-1 Meters
The wavelength of a microwave with a frequency of 2450 mhz is 1.2245 x 10⁻¹ meters.
What is wavelength?The wavelength is the time period or spatial period between the periodic wave and the distance between two waves. A microwave is a form of electromagnetic radiation.
The frequency of a microwave, f = 2450 MHz
We need to find the wavelength and the period of the microwaves
c = f λ
c = speed of light = 3 x 10 m/sec. 8 c = λf where λ = wavelength, f = frequency. Length
The relation between the wavelength and frequency is given by
The speed of light = wavelength x frequency
3 x 10⁸ m/s = wavelength x 24500 Hz
Wavelength = .12245 meters
1.2245 x 10⁻¹ Meters
Therefore, the wavelength of a microwave with a frequency of 2450 MHz is 1.2245 x 10⁻¹ meters.
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The exothermic reaction between solid aluminium powder and solid manganese (IV) oxide, produces solid manganese and
another product. How many moles of aluminium powder are needed to produce 203.7 grams of manganese?
The number of moles of aluminum powder needed to produce 203.7 grams of manganese is 5 moles.
How to calculate the number of moles of Aluminium powder?Heat, Mn, and Al2O3 are produced when aluminum powder and manganese dioxide are heated.
[tex]3MnO_{2} + 4Al - > 3Mn + 2Al_{2} O_{3} + Heat[/tex]
The balanced chemical equation in this situation indicates that there are 3 moles of manganese and 4 moles of aluminum involved in the reaction, which results in a 3:4 mole ratio.
You may make use of this mole ratio by calculating how many moles of aluminum are required to react with the 203.7g of Manganese. So,
Firstly, the mass of Aluminium has to be taken out
Let the mass be considered x.
So, the number of moles of Aluminium = x/27
Number of moles of Manganese = 203.7/54
Hence, the mass x will be,
[tex]x = 4 *203.7 * 27 / 3 * 54[/tex]
[tex]x = 135.8g[/tex]
Hence, the number of moles of Aluminium is = 135.8/27 = 5 moles.
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7.0 mol Mn reacts with 5.0 mol
O2 according to the equation below:
2Mn + O₂ → 2MnO
How many moles of MnO form from
5.0 mol Mn?
[?] mol MnO
Round your answer to the tenths place.
5 moles of MnO form from 5.0 mol Mn. Details about stoichiometry can be found below.
How to calculate number of moles?The number of moles of a substance can be calculated stoichiometrically as follows:
According to this question, the following chemical equation is given as follows:
2Mn + O₂ → 2MnO
2 moles of Mn forms 2 moles of MnO
Hence, 5 moles of Mn will form 5 × 2/2 = 5 moles of MnO.
Therefore, 5 moles of MnO form from 5.0 mol Mn.
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Answer: 10.0
Explanation: i took the test
Ordinary water boils at 100°C. Can it be made to boil at 95°C or 105°C.
It can be done. Normally the boiling point of water is 100°C. It will boil at temperature greater than 100°C more quickly. Water can be boiled at 95°C but for that the atmospheric pressure of the water should be decreased which will decrease the boiling point of water.
Concept :To boil water at 95°C, decrease the atmospheric pressure.
At 105°C, the water will be boiling quickly than normal at 100°C.
The best way is add alcohol .
The common way is that decrease the atmospheric pressure .
This will work as per Boyles law ,and boiling point can be decreased.
but it has few restrictions
You can't decrease pressure simply at normal conditionsFor decreasing pressure you have to go hill tops .Hence there is a spare way
Add alcoholGeneral alcohols like ethanol,butanol can decrease the boiling point of water
Ripening is a _______________ and spoiling is a ______________.
A. Chemical reaction, chemical reaction.
B. Physical reaction, chemical reaction.
C. Physical reaction, physical reaction.
D. Chemical reaction, physical reaction.
Answer:
A
Explanation:
The answer to this question is A. Both ripening and spoiling are chemical reactions.
Spoiling is a chemical reaction because spoiled food has bad smell and taste and it changes colour too.
Ripening of fruits is a chemical change. For example the colour could change as well as the texture.
Answer:
option a) chemical reaction, chemical reaction.
Explanation:
Changes in which new substances with different properties are formed are called chemical changes. Cooking of food, burning of substances are chemical changes as entirely new substances are formed. Burning of a candle wax releases carbon dioxide and water vapour (new substances). in here ripening and spoiling is a change that cannot be reversed which makes it a chemical change.
Which would be a good use for an organic substance? Check all that apply. A. Electrical conductors B. Waterproof coatings C. Fuels such as gasoline D. Microchips E. Plastic storage containers
Answer:
B. waterproof coatingExplanation:
please mark me brainlistName 20 chemical changes in our daily environment
Answer:
chemical reactions In our daily environment are
1) Cooking food
2) Photosynthesis
3) rusting
4) painting
5) respiration
6) combustion
7) Electrochemistry (including chemical batteries)
8)Digestion
9)Soap and detergent reactions
10)Acid-base reactions
11) fermentation
12) oxidation
13 ) burning of paper
14) riping of fruits
15) frying egg
16) souring of milk
17) baking
18) heating sugar
19) burning wood
20) rising bread
Consider the compound calcium nitrate, Ca(NO3)2. Which statements are true about this compound? Check all that apply. There are two atoms of oxygen. There are six atoms of oxygen. There are two nitrogen atoms. There are two calcium atoms.
Calcium nitrate is made up of 6 oxygen atoms, 2 nitrogen atoms and one calcium atom.
Ca(NO₃)₂
Calcium nitrate is a compound consisting of calcium, nitrogen and oxygen compoundsIt is an inorganic compoundIt is water-absorbent and absorbs moisture from airCalcium nitrate has two forms, hydrous and anhydrousBoth forms are colourless and odourlessThe reaction to form Calcium nitrate is Ca + 2NO₃ -----> Ca(NO₃)₂The number of oxygen atoms is: 2x3 = 6The number of nitrogen atoms is: 2x1= 1There is 1 calcium atomThus, calcium nitrate is made up of 6 oxygen atoms, 2 nitrogen atoms and one calcium atom.
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Answer:
B)There are six atoms of oxygen.
C)There are two nitrogen atoms.
Explanation:
edge 2023