Night-vision goggles work by detecting ________ when it's dark outside.
A. visible light
B. radio waves
C. ultraviolet light
D. infrared radiation
Final answer:
Night-vision goggles use infrared radiation to create visible images in low light or total darkness by detecting the thermal energy emitted by objects, which is more intense in the infrared spectrum.
Explanation:
Night-vision goggles work by detecting infrared radiation when it's dark outside. This technology relies on the thermal energy emitted by objects, which is more intense in the infrared spectrum and is not visible to the human eye. Unlike visible light, infrared radiation can be detected in low-light conditions or even in total darkness, allowing night-vision devices to create a visible image for the user.
Infrared radiation is part of the electromagnetic spectrum. Your eyes cannot see infrared radiation, but it can be felt as warmth on the skin. For example, reptiles can detect infrared radiation emitted by their prey, even though it's outside the human visual spectrum. Night-vision technology harnesses this invisible radiation to provide visibility in the absence of light.
The correct answer to the question is therefore D. Infrared radiation.
Energy is released during which phase changes
When two atoms of 2H (deuterium) are fused to form one atom of 4He (helium), the total energy evolved is 3.83 × 10-12 joules. What is the total change in mass (in kilograms) for this reaction?
Final answer:
To calculate the total change in mass for the fusion of two deuterium atoms into helium, we use Einstein's equation E = Δmc^2, which results in a mass change of approximately 4.258 × 10^-29 kg.
Explanation:
When two atoms of 2H deuterium fuse to form one atom of 4He helium, the energy evolved is 3.83 × 10^-12 joules. To find the total change in mass (Δm) for this reaction, we use Einstein's equation E = Δmc^2, where E is the energy released, c is the speed of light in a vacuum (approximately 3 × 10^8 m/s), and Δm is the change in mass. By rearranging the equation to Δm = E/c^2 and substituting the given values, we get Δm = (3.83 × 10^-12 joules) / (9 × 10^16 m^2/s^2) which results in a change in mass of approximately 4.258 × 10^-29 kg.
Calculate the mass of water produced when 4.86 g of butane reacts with excess oxygen.
When 4.86g of butane reacts with excess oxygen, 7.53g of water is produced. This calculation is based on stoichiometry principles and the balanced chemical equation of the reaction.
Explanation:The subject of this question is Chemistry and it pertains to the reaction of butane (C4H10) with oxygen (O2) to produce carbon dioxide (CO2) and water (H2O). The balanced chemical equation for this reaction is 2C4H10 + 13O2 -> 8CO2 + 10H2O. The mass of water produced can be calculated through stoichiometry, which is the method of calculating the quantitative/weight relations of reactants and products in a chemical reaction.
Given the weight of butane is 4.86g, we first need to convert this to moles. The molar mass of butane is calculated by adding the molar masses of Carbon (C=12.01g/mol) x 4 and Hydrogen (H=1.01g/mol) x 10. This equals approximately 58.12g/mol. Therefore, the number of moles of butane we have is 4.86g / 58.12g/mol = 0.0836 moles.
From the balanced equation, we can see that two moles of butane produce ten moles of water. Therefore, 0.0836 moles of butane would produce 0.0836 x 10/2 = 0.418 moles of water. To convert this to mass, we multiply by the molar mass of water, which is 18.01g/mol. Hence, 0.418 moles x 18.01g/mol = 7.53g of water.
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The reaction of 4.86 g of butane with excess oxygen produces approximately 7.53 g of water. This is determined using the molar mass of butane, the balanced chemical equation, and stoichiometry.
Explanation:The chemical reaction of butane (C₄H₁₀) with oxygen (O₂) to produce carbon dioxide (CO₂) and water (H₂O) is given by the balanced equation 2C₄H₁₀ + 13O₂ -> 8CO₂ + 10H₂O. In this reaction, 2 moles of butane produce 10 moles of water. The molar mass of butane is 58.12g/mole. Thus, 4.86 g of butane is 4.86 g / 58.12 g/mole = 0.0836 moles.
By stoichiometry, 0.0836 moles of butane would produce 0.0836 moles x (10 moles of water / 2 moles of butane) = 0.418 moles of water. As the molar mass of water is approximately 18.02 g/mole, the mass-produced would be 0.418 moles x 18.02 g/mole = 7.53 g. Thus, 4.86 g of butane reacts with excess oxygen to produce approximately 7.53 g of water.
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PLEASE HELP ASAP!!!
Which statement about the following reaction is correct?
CH4 (g) + 2O2 (g) yields CO2 (g) + 2H2O(l) deltaH = -890 kJ
reacting one mole of oxygen (O2) absorbs 445 kJ of energy
reacting one mole of oxygen (O2) releases 445 kJ of energy
reacting one mole of methane (CH4) absorbs 890 kJ of energy
reacting two moles of methane (CH4) releases 890 kJ of energy
Final answer:
The correct statement is that reacting one mole of oxygen (O2) releases 445 kJ of energy during the exothermic reaction of CH4 with O2.
Explanation:
The correct statement about the reaction CH4 (g) + 2O2 (g) → CO2 (g) + 2H2O(l) ΔH = -890 kJ is that reacting one mole of oxygen (O2) releases 445 kJ of energy. The reaction is exothermic, meaning it releases energy. The ΔH value of -890 kJ means that for every mole of methane (CH4) that reacts, 890 kJ of energy is released. Considering the stoichiometry of the reaction, where 2 moles of oxygen react per mole of methane, half of the total energy release (which is 890 kJ) would be associated with 1 mole of oxygen, thereby releasing 445 kJ.
What is the definition of force
among atoms with low atomic numbers what is the neutron-proton ratio of the most stable nuclei
The stable neutron-proton ratio in lighter elements is about 1:1, exemplified by Carbon-12. As element atomic numbers increase, the ratio tends to 1.5:1 to maintain nuclear stability, noticeable in heavier elements like lead-206. All elements with Z > 83 are inherently unstable and radioactive.
Among atoms with lower atomic numbers, the most stable nuclei typically have a neutron-proton ratio that approximates 1:1. This means that in lighter elements, the number of neutrons and protons are nearly equal, contributing to the stability of the nucleus.
A classic example is Carbon-12, which has six protons and six neutrons. As we examine heavier elements, the stable neutron-proton ratio increases, which can be attributed to the need to counterbalance the increased electrostatic repulsion between protons within the nucleus. For instance, heavy elements such as lead-206 have a neutron-proton ratio of about 1.5:1, with 124 neutrons to 82 protons.
Regardless of the number of neutrons, it should be noted that all elements with atomic number (Z) greater than 83 are unstable and radioactive. The balance in neutron-proton ratio is crucial as it determines the type of radioactive decay a nuclide may undergo, such as positron emission or electron capture, especially if the ratio is not within the stable range.
Which substance is acting as the Brønsted-Lowry acid in the following chemical reaction? NH4 + OH- yields NH3 + H2O
A. NH4+
B. OH-
C. NH3
D. H2O
Match each type of energy with its description or example.
light
heat
chemical
mechanical
electrical
A.
the energy in your food is an example
B.
the kinetic energy of moving water is an example
C.
total kinetic energy of all the atoms that make up a sample of matter
D.
form of energy visible to the human eye
E.
caused by the movement of electrons
Answer:
A: Chemical
B: Mechanical
C: Heat
D: Light
E: Electrical
Explanation:
A: The energy in food is known as chemical energy. Chemical energy is the energy which is stored in the molecular bonds of the compounds (eg. glucose). Hence, when food is digested, many molecules are broken down to their most basic components.
B: Energy that can be used to "do work" is known as mechanical energy. Mechanical energy is energy (usually kinetic and potential energy) which is used to produce a force to an object, and in this conversion, the object then does work (eg. A body of water being used to push a turbine to create electricity).
C: The kinetic energy in atoms/molecules while vibrating is known as heat. Heat energy can be measured as the temperature of a certain substance, but it is actually the sum of all the kinetic energy of every single molecule/atom
D: The energy given off by the sun which allows us to view our surroundings is known as light energy. Light energy enters our eyes and is converted to an electrical impulse that our brain interprets as colour.
E: When electrons move from atom to atom, this is known as electrical energy. This energy is usually found as a property of metals, where they have a "sea" of localised electrons that can allow for the conduction of electricity
What is the term for a substance that acts on proton donor in one reaction and as a proton acceptor in another?
Phosphorus has an atomic mass of 31 and an atomic number of 15, so the number of neutrons must be _______________.
sorry i'm late:
16 (how to get answer is shown below on second photo):
Gas in a balloon occupies 3.3 L. What volume will it occupy if the pressure is changed from 100.0 kPa to 90.0 kPa (at constant temperature).
When the pressure is decreased from [tex]100.0 kPa[/tex] to [tex]90.0 kPa[/tex] at constant temperature, the volume of the gas in the balloon increases to [tex]3.67 L[/tex].
To solve this problem, we can use Boyle's Law, which states that for a given mass of gas at constant temperature, the volume of the gas is inversely proportional to its pressure. Mathematically, this can be expressed as:
[tex]\[ P_1V_1 = P_2V_2 \][/tex]
where [tex]\( P_1 \)[/tex] and [tex]\( V_1 \)[/tex] are the initial pressure and volume, and [tex]\( P_2 \)[/tex] and [tex]\( V_2 \)[/tex] are the final pressure and volume, respectively.
Given:
Initial volume [tex]\( V_1 = 3.3 \) L[/tex]
Initial pressure [tex]\( P_1 = 100.0 \) kPa[/tex]
Final pressure [tex]\( P_2 = 90.0 \) kPa[/tex]
Temperature is constant
We want to find the final volume [tex]\( V_2 \)[/tex]. Rearranging Boyle's Law to solve for [tex]\( V_2 \)[/tex], we get:
[tex]\[ V_2 = \frac{P_1V_1}{P_2} \][/tex]
Substituting the given values:
[tex]\[ V_2 = \frac{100.0 \text{ kPa} \times 3.3 \text{ L}}{90.0 \text{ kPa}} \][/tex]
[tex]\[ V_2 = \frac{330}{90} \text{ L} \][/tex]
[tex]\[ V_2 = 3.67 \text{ L} \][/tex]
Which of the following are indicators of a chemical change? Select all that apply.
color change
temperature change
precipitate formation
gas formation
cutting a solid into smaller pieces
How many kilojoules are required to convert 115.0 g of ice at 0.0 ∘c to liquid water at 32 ∘c? the heat of fusion of water is 334 j/g, and the heat capacity of water is 4.184 j/g ∘c?
To convert 115.0 g of ice at 0.0 ∘C to liquid water at 32 ∘C, 53.821 kJ of energy is required.
To determine how many kilojoules are required to convert 115.0 g of ice at 0.0 ∘C to liquid water at 32 ∘C, we need to account for both the phase change and the temperature increase.
Melt the ice: The heat of fusion of water is 334 J/g.Therefore, 53.821 kJ are required to convert 115.0 g of ice at 0.0 ∘C to liquid water at 32 ∘C.
2kl(aq)+cl(g) 2kcl (aq) +l2(g) how many moles of L2 are produced
What is the total number of electrons in all s orbitals of a neutral atom of phosphorus?
Wood, Iron, Glass, Paper, Nickel Which substances show magnetic property?
Question 3 what geometric arrangement of charge clouds is expected for an atom that has five charge clouds? trigonal bipyramidal square planar octahedral tetrahedral
AX5E0 - trigonal bipyramidal - zero lone pairs;
AX4E1 - seesaw - 1 lone pair;
AX3E2 - T-shaped - 2 lone pairs;
AX2E3 - linear - 3 lone pairs;
The only option that matches is trigonal bipyramidal.
What happens to the volume of a sugar solution as more sugar is dissolved in it?
how many parts per million of mercury are there in a sample of tap water with a.mass of 750 g containing 2.2 mg of hg
How many grams of carbon dioxide are produced from the combustion of 1.3 moles of acetylene
why do volcanoes erupt?
Question 1 how much water would you add to 175 ml of 6.00 m hydrochloric acid to prepare a 2.00 m solution of this acid? 350 ml 700. ml 58.3 ml 525 ml none of the above
Answer:
350 mL
Explanation:
Given:
concentration of stock solution of HCl =6.00 M
Volume of stock solution of HCl = 175 mL
concentration of required solution = 2.00 M
total volume of required solution = to be determined
This is problem of dilution. We have to determine the total volume of required solution to be made, from the given stock solution.
We will use
M₁V₁=M₂V₂
Where
M₁=concentration of stock solution
V₁= volume of stock solution
M₂=concentration of required solution
V₂=volume of required solution
Putting values
6X175=2XV₂
V₂=525 mL
so total volume of required solution formed will be 525 mL
We have already 175 mL of solution in it. The water need is difference of these two volume.
water added = 525-175= 350 mL
how many moles of 18L of NH3 at 30 celcius and 912 mmHg? how many grams?
This is for a study guide for my semester final, and I have no clue how to answer this, please help, and please at least try to help!
Besides the major types of radioactive decay, there are two others: positron emission and electron capture.
• Compare and contrast positrons with electrons.
• Explain how positron emission works and how it causes transmutations.
• Explain how electron capture works and how it causes transmutations.
• Compare the transmutations caused by positron emissions and electron capture.
Positron emission = emission of a positron and a neutrino when a proton is convert into a neutron. The total number of particles in the nucleus doesn't change, -1 proton +1 neutron
It's a spontaneous reaction for some nucleus.
eg:
Positron = e+
Neutrino=ve
O-15 --> N-15 + e+ +ve
Electron capture= A nucleus absorb an electron while a proton is convert in a neutron and emit a neutrino. The total number of particles in the nucleus doesn't change, -1 proton +1 neutron
eg:
Al-26 +e- --> Mg-26 + ve
Electron capture and positron emission are two mechanisms to explain the decay of some unstable isotopes. Electron capture is usually observed when the energy difference between the initial and final state is low. Mainly because of the larger amount of kinetic energy need for the expulsion two particles with the positron emission mechanism.
What is the molarity of a solution that contains 3.25 moles of nano3 in 250. ml of solution?
The molarity of the solution is determined by dividing the number of moles of solute by the volume of the solution in liters, resulting in a molarity of 13.0 M for the sodium nitrate (NaNO3) solution.
Explanation:To calculate the molarity of the NaNO3 solution, we will use the formula of molarity, which is the number of moles of solute divided by the volume of the solution in liters. The student has provided that there are 3.25 moles of NaNO3 in 250 mL of solution.
To use the formula, we must convert the volume from milliliters to liters. Since 1000 mL equals 1 L, we divide the volume provided by 1000.
Volume in liters = Volume in mL / 1000 = 250 mL / 1000 = 0.250 L
Now, using the molarity formula:
Molarity (M) = Moles of solute / Volume of solution in liters = 3.25 moles / 0.250 L
M = 13.0 M
Explain how deforestation can cause a disruption to the carbon cycle
Deforestation disrupts the carbon cycle by reducing the removal of carbon dioxide from the atmosphere through photosynthesis and releasing stored carbon through burning wood and fossil fuels. This contributes to climate change.
Explanation:Deforestation can cause a disruption to the carbon cycle in several ways. Firstly, trees and plants remove carbon dioxide from the atmosphere and store it in their structure through photosynthesis. When forests are cleared, this process is reduced, leading to increased levels of carbon dioxide in the atmosphere. Additionally, the burning of wood and fossil fuels during deforestation releases stored carbon back into the atmosphere. These disruptions to the carbon cycle contribute to climate change and an imbalance in the Earth's temperature regulation.
Keywords: deforestation, carbon cycle, climate change, carbon dioxide, photosynthesis
What term refers to group behavior seen in animals of a similar type?
Answer:
The correct answer is swarm behavior.
Explanation:
Swarming or swarm behavior is a collective behavior demonstrated by entities, mainly the animals of same size that accumulate together, specifically moving in masses or migrating in some direction or milling about the same spot. As a term, swarming is applicable mainly to insects, however, it can also be applied to any other animal or entity, which demonstrates swarm behavior.
Which waves move by replacing one particle with another? A) light waves B) sound waves C) electrostatic waves D) electromagnetic waves
There are 2 classifications of waves according to the media of propagation.
Mechanical Waves – needs a medium, an example is sound waves. Sound waves do not travel through a vacuum. Sound waves move by replacing one particle with another. Particles vibrate and that is why we hear the sounds. Electromagnetic Waves and electrostatic waves are one but the same. They do not require a medium. – an example is light waves.i think it is B) because Sound waves move by replacing one particle with another. Sound waves require a medium to propagate, or move. Light and electromagnetic waves do not require a medium. Electrostatic are not a type of wave.
hope this helps
Which statement correctly describes an atom of the element helium?
A. An atom of helium has eight electrons in its outer energy
B. An atom of helium most similarly behaves like an atom of hydrogen since it is in the same period.
C. An atom of helium has a full outer energy level and is therefore unusually reactive.
D. An atom of helium has its valence electrons in its first energy level.
Answer:
Option c
Explanation:
Atomic number of helium is 2.
Electronic configuration of He = [tex]1s_2[/tex]
First energy shell of an atom is known as K shell. It has only one sub shell 's sub shell'.
K shell or energy level can accommodate maximum of 2 electrons. Helium has 2 electrons and these two electrons are filled in K shell. So, atom of helium has a full energy level.
Elements having full energy level or eight electrons in their valence shell is stable and therefore chemically inactive or inert.
As outer shell of helium is full, so it is chemically inactive.