help Light reflecting from the aluminum coating on a CD ____________ and then interferes.
A. Diffracts
B. Refracts
C. Vibration
D. Reflection
Answer:
Reflection
Hope it will help you
[h+] for a solution is 2.65 x 10-2 m. this solution is a. acidic basic c. neutral
help will give brainliest
Answer:
A. acidic
Explanation:
Al2O3(s)+3CO(g)→2Al(s)+3CO2(g) Express your answer in kilojoules to one decimal place.
Based on the standard heat of formation of aluminium oxide, the heat of the reaction of the decomposition of aluminium oxide is +3339.6 kJ
What is the heat of reaction?The heat or enthalpy of a reaction is the amount of heat evolved or absorbed when reactant molecules when reactants form products.
Considering the given reaction:
2 Al2O3(s) -> 2 Al(s) + 3 O2(g)The heat of formation of aluminum oxide is -1669.8 kJ/mol.
The heat of the reaction of the decomposition of aluminium oxide is calculated as follows:
Heat of reaction = Heat of formation of products - Heat of formation of reactants
Heat of reaction = {3 × ΔHf°O2 (g) + 2 × ΔHf° Al(s)} - 2 × ΔHf° Al2O3 (s)
Since the standard enthalpy of formation,ΔHf°, of an element in its most stable form is equal to zero.
ΔH°rxn = (3 × 0 + 2 × 0) - 2 × -1669.8 kJ/
ΔH°rxn = +3339.6 kJ
Therefore, the heat of the reaction of the decomposition of aluminium oxide is +3339.6 kJ
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26. Which temperature change indicates an increase
il the average kinetic energy of the molecules in
a sample?
(1) 255 K to 0°C
(2) 355 K to 25°C
(3) 115°C to 298 K
(4) 37°C to 273 K
The temperature change that indicates an increase in the average kinetic energy of the molecules in a sample is 255 K to 0°C.
How does reactions occur?Chemical reactions occur when particles of reactants react or collide with one another, hence, when particles collide faster, reaction also occurs faster.
One of the ways to make reactions occur faster i.e. increasing the average kinetic energy is by increasing the temperature.
The example that depicts an increase in temperature is 255K to 0°C, which is equivalent to 255K to 273K.
Therefore, the temperature change that indicates an increase in the average kinetic energy of the molecules in a sample is 255 K to 0°C.
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Explain how matter is conserved on a molecular scale when ionic compounds dissociate in solution ?
The matter is conserved on a molecular scale when ionic compounds dissociate in solution in the form of solvated ions.
What are ionic compounds?Ionic compounds are those compounds which are formed due to high attractive electrostatic force between the cation (positively charged ion) and anion (negatively charged ion) of any substance.
When a solid ionic compound dissolve in any solution then they will shows dissociation reaction as a result of which we get their ions uniformly distributed in the solution. As water molecule is also polar and ionic compounds are also polar that's why they show complete dissolving in water due to dissociation.
Hence in molecular scale we get it in the form of solvated ions.
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How many atoms are in a 250 g sample of Gold
Answer:
15.055 X 1023 atoms
Explanation:
hope clear
10 A fixed quantity of gas is placed inside a container of fixed volume at a temperature of
27°C. The gas has a pressure, P.
Which expression shows the pressure of the gas at 57°C?
A P2=(27/57) P
B
P2=(57/27) P
P2=(300/330) P
с
D
P2=(330/300) P
A gas has a pressure P at 27 °C. To calculate its pressure at 57°C we use an expression derived from Gay-Lussac's law:
C) P2 = (300/330) P
What does Gay-Lussac's law state?Gay-Lussac's law states that the pressure of a given mass of gas varies directly with the absolute temperature of the gas when the volume is kept constant.
Mathematically, it can be written as:
P/T = k
A gas has a pressure P at 27 °C and we want to find the expression to calculate its pressure at 57°C.
Step 1: Convert the temperatures to the Kelvin scale.We do so by summing 273.15.
K = 27 + 273.15 = 300 K
K = 57 + 273.15 = 330 K
Step 2: Apply Gay-Lussac's law.P2/330 = P/300
P2 = (300/330) P
A gas has a pressure P at 27 °C. To calculate its pressure at 57°C we use an expression derived from Gay-Lussac's law:
C) P2 = (300/330) P
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Convert −5 ◦C to Kelvin.
Which option correctly describes the reactants and products of a chemical reaction?.
Answer:
Chemical reaction occurs when chemical bonds between atoms are formed or broken . The substance that go into a chemical reactions are called reactants, and the substance produced at the end of the reaction are known as the product .
Consider the two triangles shown below.
Note: The triangles are not drawn to scale.
Triangles may be regarded as similar or congruent on the following basis;
1) Side angle side (SAS)
2) Side side side (SSS)
3) Angle Angle side (AAS)
What is a triangle?A triangle is a three sided figure. The figures are not shown here. However, two triangle may be regarded as similar or congruent by the following conditions;
1) Side angle side (SAS)
2) Side side side (SSS)
3) Angle Angle side (AAS)
Since the triagles are not shown here, the similarity of the triangles can not be established.
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How many molecules of water are made from 2 molecules of h2?
Answer:
Given the balanced reaction, note that there are two molecules of water produced for every two molecules of H2
Explanation:
There are two molecules of water is produced from 2 molecules of hydrogen.
What is hydrogen?It is the lightest element which is colorless, tasteless, and non-toxic.
Water is made up of hydrogen and oxygen, with a good amount of heat to carry out the reaction.
The equation is
[tex]\rm 2H_2O + O_2 = 2H_2O[/tex]
It is clear that two molecules of hydrogen produce two molecules of water.
Thus, there are two molecules of water is produced from 2 molecules of hydrogen.
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Write a paragraph, citing examples from the text, to explain how Dr.
Paul Chirik's process could result in the development of flexible
manufacturing technologies.
Paul J. Chirik developed methods associated with chemistry catalysis and transition metals, which may result useful for the development of manufacturing technologies.
What is catalysis?Catalysis refers to the chemical processes that increase the rate of different types of reactions by lowering its activation energy.
Proteins (enzymes) are biological catalysts that increase the rate of chemical reactions in biological systems.
Catalysis may be reached by using transition metals (e.g., actinium and rutherfordium), which result useful in the development of manufacturing technologies.
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b
Identify a compound composed of
molecules
Answer:
nitrogen oxides and hydrogen
How long does sucrose take to decompose? Why?
I need help!
Answer:
The loss of crystalline structure of sucrose was reported at various temperatures, but decomposition, after >50 h of holding at 120 °C in a sealed pan.
Explanation:
As this condition is above the melting temperature of fructose (a possible first decomposition product), and there were water and impurities.
what is fractional distinction
Explanation:
which one of the following a correct way of finding current?
According to the kinetic-molecular theory, what is one way the three states of matter are all similar?
The kinetic molecular theory of matter states that:
1. Matter is made up of particles that are constantly moving.
2. A change in phase may occur when the energy of the particles is changed.
3. All particles have energy, but the energy varies depending on the temperature the sample of matter is in. This in turn determines whether the substance exists in the solid, liquid, or gaseous state.
The part of an atom that is responsible for the bonding of atoms is
Answer:
the answer is electrons
Explanation:
electrons are responsible for the chemical bonding.
What's the volume of 0.2 mol of hydrogen at STP.
5.6 L
22.4 L
4.48 L
2.24 L
Answer:
22.4
Explanation:
Describe how electron arrangements are given using Lewis structures.
Answer:
The Lewis structure indicates that each Cl atom has three pairs of electrons that are not used in bonding (called lone pairs) and one shared pair of electrons (written between the atoms). A dash (or line) is sometimes used to indicate a shared pair of electrons: A single shared pair of electrons is called a single bond.
Explanation:
How would you describe the temperature of an object that has very slow moving particles?
5. Summarize: What do you think would happen to the convection currents in the atmospheres and
along the coastlines if the surface of the Earth warmed up? Do you think this could have any affect
on the convection in the mantle? Why or why not? Your answer should be at least 3 sentences in
length,
Answer:
Explanation:
Image result for Summarize: What do you think would happen to the convection currents in the atmospheres and along the coastlines of the surface of the Earth warmed up? Do you think this could have any affect on the convection in the mantle? Why or why not? Your answer should be at least 3 sentences in length,
As the magma cools and solidifies, the convection currents will stop and the Earth will become geologically dead.
In addition to not causing damage to the sample, what is another advantage of using a microspectrophotometer to analyze fibers?
The fiber’s spectra can also be polarized.
The sample can be quite small.
The sample can originate from a known source.
The fiber sample’s dye can be extracted.
Another advantage of advantage of using a microspectrophotometer to analyze fibers asides not causing damage to the sample is that the sample can be quite small.
What is a microspectrophotometer?Microspectrophotometry is a biological technique used to measure the absorption or transmission spectrum of a solid or liquid material in either transmitted or reflected light.
Microspectrophotometry can also measure the emission of light by a sample, which is usually small as the micro implies.
One advantage of microspectrophotometry is that the sample does not get damaged. However,
However, another advantage of advantage of using a microspectrophotometer to analyze fibers asides not causing damage to the sample is that the sample can be quite small.
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1. Illustrate and describe the sequence in which ten electrons occupy the five
orbitals related to an atom's d sublevel.
Calculate the mass percent of water in the formula:
MgSO4.7H20
Please help me and explain how you got it I gotta pass my chem class pls help!
Answer:
%H20=
(14xH)+(7xO)______________________________ X 100(Mg) + (S) + (4 x O) + (14 x H) + (7 x O)Thus,(14 x 1.008) + (7x16.0)______________________________________ X 10024.31 + 32.06 + (4x16.0) + (14 x 1.008) + (7x16.0)=126.122_____________ X 100246.482= 0.512 x 100=51.2%There is 51.2% of water is Magnesium Sulphate-7-water.
Why are xrays used to probe the crystal structure of a material
Answer:
Because X-rays have wavelengths similar to the size of atoms
X rays are used to probe the crystal structure of a material because this have same wavelength as atoms of crystal have.
What are x rays?X rays are the type of electromagnetic radiations and it is produced when the fast moving electron collide with the target anode and sudden deceleration takes place.
X rays have the high energy so that it easily penetrate in any crystal molecule as they also have same wavelength as atoms of the crystals have.
Hence due to high energy and same wavelength was of atoms of crystal it is used to probe the crystal.
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4. How many atom are in
C3H5(NO3)3
Answer:
carbon = 3
hydrogen=5
nitrogen=3
Oxygen=9
The world is divided into large areas based on their average temperatures and precipitation. what are these areas called?
climate continents
climate zones
global areas
global regions
The world is divided into large areas based on their average temperatures and precipitation is called climate zones.
What is climatic zone?The principal zones that are demarcated by lines of latitude due to which the earth can be divided on the basis of climate. Tropical zone, Subtropics zone, Temperate zone and Cold zone are the four types of climatic zones.
So we can conclude that large areas based on their average temperatures and precipitation is called climate zones.
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The world is divided into large areas called climate zones based on their average temperatures and precipitation.
What are climate zones?Climate zones are areas of the Earth that results from differences in climate such as temperature, humidity, amount of precipitation etc.
Climate zones of the globe are as follows:
Temperate Arctic or polarSubtropical TropicalTherefore, it can be said that the world is divided into large areas called climate zones based on their average temperatures and precipitation.
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Calculate the number of grams nitric acid (HNO3) in 375 L of a 1.00 M solution.
List three reasons why nonvascular plants are important
Answer:
They are food for some animals. Some animals use them for nesting material. Humans can dry and burn some types of nonvascular plants as a fuel.
Explanation:
Some nonvascular plants produce various nutrients that are passed to the soil and can be used by other plants. Also, nonvascular plants that cover a large surface area help maintain the cohesion of the land by reducing the risk of erosion. Nonvascular plants are also very important to animals.
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Hello people ~
Friction always
(a) opposes the motion
(b) helps the motion
(c) both (a) and (b)
(d) none of these
Answer:
Opposes the motion
Explanation:
Let's take an example
Suppose you kicked a ball and the ball is doing down the groundThe friction makes the ball to stop after sometime .So it opposed the ball's motionoption A is correct