THIS IS A SCIENCE QUESTION
Which choice describes how temperature differences affect air?
A. Hot air rises, and cold air sinks.
B. Hot air sinks, and cold air rises.
C. Hot air is steady, and cold air moves fast.
D. Hot air moves fast, and cold air rises.
Answer:
A
Explanation:
Hot air is less dense therefore it rises. Cold air is more closely packed therefore it is more dense. Less dense things rise while more dense things sink.
Answer:
A
Explanation:
Think of it like an hot air balloon
Hot air makes it rise and cool air sinks it downwards
Need help!! (10 Points)
which liquid is the most viscous and why?
Find the enthalpy for a constant pressure calorimetry reaction where the reaction occurs in a 250ml aqueous solution. The temperature changes from 25.0c to 26.1 c
Assume that cool = 4.18j/gt
Answer:
[tex]\Delta H=1149.5J[/tex]
Explanation:
Hello!
In this case, since the calorimeter contains a solution for which the specific heat is 4.18 J/g°C, which is equal to that of the water, we can also notice that the density is 1.00 g/mL and therefore the present mass is 250 g. In such a way, we compute the enthalpy change as shown below:
[tex]\Delta H=mC\Delta T[/tex]
Thus, by plugging in the mass, specific heat and temperature change, we obtain:
[tex]\Delta H=250g*4.18\frac{J}{g\°C}(26.1\°C-25.0\°C)\\\\\Delta H=1149.5J[/tex]
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Answer the following questions about the last lesson below. What did we figure out about chain reactions? What did we figure out about fission? Fission produce more energy than a typical fuel sources, chain reaction
Answer:
(Nothing)-But No answer
Oxidation of 1-pentanol could produce 1-pentanal and 1-pentanoic acid
At the south Texas nuclear power plant, uranium atoms are split in order to create heat. The heat is used to make steam, which turns a generator to make electricity. What energy changes takes place during this process?
A-Chemical energy to nuclear energy to electrical energy to heat energy
B-Mechanical energy to nuclear energy to heat energy to light energy
C-mechanical energy to heat energy to chemical energy to electrical energy
D-nuclear energy to heat energy to mechanical energy to electrical energy
Answer:
Inside the reactor
In a nuclear reactor the uranium fuel is assembled in such a way that a controlled fission chain reaction can be achieved. The heat created by splitting the U-235 atoms is then used to make steam which spins a turbine to drive a generator, producing electricity.
If the root word "derm” means "skin,” which of these words means "the study of skin diseases and treatment”? dermatologically dermatological dermatologist dermatology
Answer:
it would be dermatology
Explanation:
the first two dont make sense, and a dermatologist is the doctors themselves, so therefore dermatology is the study of it
How red blood cells different to animal cells
Answer:
By contrast, the red blood cells of mammals lack nuclei and other internal structures found in most animal cells. This simplification allows mammal red blood cells to carry more gas-transporting proteins and to squeeze through smaller blood vessels.
Explanation:
Which characteristic applies to all mixtures?
Answer:
A mixture is the blending of two or more dissimilar substances. A major characteristic of mixtures is that the materials do not chemically combine. Mixtures can be divided into those that are evenly distributed (homogeneous) and those that aren't (heterogeneous).
Explanation:
Answer:
A mixture is the blending of two or more dissimilar substances. A major characteristic of mixtures is that the materials do not chemically combine. Mixtures can be divided into those that are evenly distributed (homogeneous) and those that aren't (heterogeneous
the increase in atomic radius as you go down the periodic table is caused by?
Answer: The number of energy levels increases as you move down a group as the number of electrons increases. Each subsequent energy level is further from the nucleus than the last. Therefore, the atomic radius increases as the group and energy levels increase.
Which substance can be decomposed by a chemical change?
a. calcium
b. potassium
c. sodium
d. sodium chloride
What physical and chemical properties should braces (used to straighten teeth possess in order to attain its desired goal to straighten the teeth) while not presenting a health hazard to the individual?
Answer: Braces are used by the people to correct the alignment and position of tooth or teeth in the jaw.
Explanation:
The teeth braces must have strong tensile strength and must create a constant pressure on the teeth so as to allow the straightening of the teeth.
The strong force of attraction between the molecules of the braces material that can be steel, nickel, molybdenum, copper, titanium. This makes the bracing material rigid on the teeth.
Which TWO statements describe the ocean floor giving brainliest pls
Answer:
i think that it is. d and b, im not completely sure but ik d is included
Explanation:
Answer:
think b and a
Explanation:
How many atoms are in 2.00 moles of titanium
Answer:
3.04 atoms
Explanation:
because of the switzer theory
What impact can limiting factors have on a population?
(a) Higher birth rate
(b) Higher death rate
(c) Stable population
(d) Lower death rate
Answer:
The answer is B. Limiting factors can lower birth rates, increase death rates.
What is the energy of an object because of its potential and kinetic energies?
chemical energy
electrical energy
nuclear energy
mechanical energy
Can yall plz answer fast!? 20 points if you arent sure its right dont bother
Answer:
The sum of an object's potential and kinetic energies is called the object's mechanical energy. As an object falls its potential energy decreases, while its kinetic energy increases. The decrease in potential energy is exactly equal to the increase in kinetic energy
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Looking at the different chemical structures, which one(s) might be able to hold
cancer fighting drugs and could then travel through the body safely until they
released the drugs into the cancer cells?
a) Graphite and diamond because these well known substances have been used
for years to treat cancer
b) Graphite because it is found in pencils and is a good lubricant
c) Fullerene and carbon nanotubes because they have empty spaces inside the
molecules
d) Diamond because it is one of the hardest substances
Answer:
c) Fullerene and carbon nanotubes because they have empty spaces inside the molecules
Explanation:
Fullerene and carbon nanotubes would be the most desired in order to hold the cancer fighting drugs and to carry them through the body safely.
These molecules have empty spaces in them. The cavities makes it possible for storage. As they pass through the body, they can be held perfectly well to their target site of action.how many atoms of oxygen are in a molecule of nitroglycerin
Answer:
i think there are 3 carbon and 5 hydrogen
Explanation:
There are 9 atoms of Oxygen in a molecule of nitroglycerin.
What is Nitroglycerin?Nitroglycerin is also called Trinitroglycerin, It is an oily, thick, colorless liquid.
A vasodilator, nitroglycerin is generally used to relieve anginal chest pain. Currently, the FDA has approved it for the acute prophylaxis of angina pectoris owing to coronary artery disease as well as the acute alleviation of an episode.
It is used in manufacturing explosives.
The molecular formula of Nitroglycerin is C₃H₅N₃O₉
The chemical formula is 1,2,3-trinitroxypropane.
A molecular formula shows the number of atoms present in the compound.
The number of atoms of Carbon present is 3.
The number of atoms of Hydrogen present is 5.
The number of atoms of Nitrogen present is 3.
The number of atoms of Oxygen present is 9.
So, the total number of atoms of Oxygen present is 9.
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At STP, one mole of oxygen and one mole of neon contain equal numbers of
Answer:
D) particles but the oxygen has a greater mass.
Explanation:
Just took the test and got it right
At STP, one mole of oxygen and one mole of neon contain equal numbers of particles but oxygen has greater mass.
What is a mole?Mole is defined as the unit of amount of substance . It is the quantity measure of amount of substance of how many elementary particles are present in a given substance.
It is defined as exactly 6.022×10²³ elementary entities. The elementary entity can be a molecule, atom ion depending on the type of substance. Amount of elementary entities in a mole is called as Avogadro's number.
It is widely used in chemistry as a suitable way for expressing amounts of reactants and products.For the practical purposes, mass of one mole of compound in grams is approximately equal to mass of one molecule of compound measured in Daltons. Molar mass has units of gram per mole . In case of molecules, where molar mass in grams present in one mole of atoms is its atomic mass.
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Why does sodium have a lower melting point then magnesium
Answer:
Number of delocalized electrons
Explanation:
Magnesium has more delocalized electrons compared to sodium and this accounts for the higher melting point.
When magnesium atoms comes together to form a metallic bonds, they have more network of delocalized electrons. There is more pull for the localized electrons due to the nuclear charge on the nucleus. This strong intermolecular metallic bond increases the melting point of magnesium.An ion that consists of 7 protons, 9 neutrons, and 10 electrons has a net charge of
Answer:
-3
General Formulas and Concepts:
Chemistry - Atomic Structure
Protons have a positive (+) chargeNeutrons have a neutral (0) chargeElectrons have a negative (-) chargeExplanation:
Step 1: Define
7 protons, 9 neutrons, 10 electrons.
+7, +0, -10
Step 2: FInd charge
7 + 0 - 10 = -3
What is MS-Word?MS Word Ki Hai hardware software Ki Hai
Answer:
Ms word is a type of application that is used to make your work more easier nd attractive.
Explanation:
For ex- you can draw a line,you can highlight your text,make your text bold and you can also increase and decrease the font size.
Which of the period 2 homonuclear diatomic molecules are predicted to be paramagnetic?
A chemist determines that a sample of petrified wood has a carbon-14 decay rate of 6.00 counts per minute per gram. The decay rate of carbon-14 in fresh wood today is 13.6 counts per minute per gram, and the half life of carbon-14 is 5730 years. What is the age of the piece of wood in years?
Answer:
6,765 years
Explanation:
Calculation to determine the age of the piece of wood in years
First step is to calculate decimal fraction of Carbon-14 that was remaining
Decimal fraction of Carbon-14= 6.00 counts per minute per gram/ 13.6 counts per minute per gram
Decimal fraction of Carbon-14 remaining= 0.4411765
Second step is to calculate the numbers of half-lives that have elapsed
(1/2)^n= 0.4411765
Hence,
n log 0.5 = log 0.4411765
n = 1.18057
Last step is to calculate the length of time that has elapsed
Using this formula
Elapsed length of time=Half life of carbon-14 *n
Let plug in the formula
Elapsed length of time=5,730 years * 1.18057
Elapsed length of time= 6,765 years
Therefore the age of the piece of wood in years will be 6,765 years
A molecule is made up of two or more atoms bonded together. True or false
Answer:
True
Explanation:
a group of two or more atoms that form the smallest identifiable unit into which a pure substance can be divided and still retain the composition and chemical properties of that substance.
2 plus 45 was near tyhe decimal value of h solve for 123v minus 45b
Answer:
47
Explanation:
Which of the following is a chemical change?
A. Boiling water using fire
B. Breathing in oxygen and breathing out carbon dioxide
C. Ripping a piece of paper in half
D. Melting gold to make jewelry
What is the pH at the equivalence point of the titration of 50.0 mL of 0.300 M NH3(aq) with 0.150 M HCl(aq)?
Answer:
pH = 5.19, at the equivalence point
Explanation:
This is titration of a weak base and a strong acid. pH in the equivalence point will be acid. To determine this pH, we know that in in the equivalence point:
mmoles base = mmoles of base
50 mL . 0.3M = 0.150 M . Volume of acid
Volume of acid = (50 . 0.3)/ 0.15 → 100 mL
Total volume of equivalence point is 50 mL + 150 mL = 200 mL
Neutralization reaction is:
NH₃ + HCl → NH₄Cl
NH₃ + H₃O⁺ ⇄ NH₄⁺ + H₂O
15 15
0 0 15
Ammonia's Kb = 1.8×10⁻⁵
In the equivalence point, we have only ammonium, beacuse all the amonia reacted to the protons. Let's make the equilibrium
NH₄⁺ + H₂O ⇄ NH₃ + H₃O⁺ Ka
I: 15 - - -
Eq: 15-x x x
Ka = 1×10⁻¹⁴ / Kb → 5.55×10⁻¹⁰
[NH₄⁺] = 15 mmoles / 200 mL = 0.075 M
In the equilibrium, we can avoid the 15 - x, because Ka is soo small.
Expression for Ka is [ NH₃ ] . [H₃O⁺] / [NH₄⁺] = 5.55×10⁻¹⁰
[H₃O⁺] = √(5.55×10⁻¹⁰ . 0.075)
[H₃O⁺] = 6.45×10⁻⁶
- log [H₃O⁺] = pH → 5.19
A radical is a reactive intermediate with a single ___ electron, formed by ___ of a covalent bond. Allylic radicals are stabilized by_____, making them ___ stable than tertiary radicals. A compound that contains an especially weak bond that serves as a source of radicals is called a radical ____. Treatment of cyclohexene with N-bromosuccinimide in the presence of light leads to___ by ___ intermediates. The stability of a radical ____ as the number of alkyl groups bonded to the radical carbon increases. Although alkanes undergo radical substitution reactions with both Cl_2 and Br_2 chlorination is ___ than bromination. A compound that prevents radical reactions from occurring is called a radical ___ Treatment of cyclohexene with bromine in an organic solvent leads to ___ by ___ intermediates. Radical halogenation reactions occur ____ racemization at a stereogenic center.
Answer:
unpaired
homolysis
more
initiator
allylic substitution
radical
increases
faster
inhibitor
addition
ionic
with
Explanation:
The list of suitable words to be used to fill in the blank spaces in the sentences have been shown in the image attached.
A radical is any specie that contains an unpaired (odd) electron. Radicals are formed by homolysis of covalent bonds.
Due to the double bond involved in resonance, allylic radicals are more stable than tertiary radicals although stability of radical increases with the number of alkyl groups present. Initiators easily supply free radicals for radical reactions.
Addition reactions are faster with Cl2 than with Br2 because chlorine is more reactive than bromine. The addition of Br2 to cyclohexene occur via ionic mechanism and ionic intermediates.
Radical halogenation reactions occur with racemization at a stereogenic center.
How many unshared electrons are found in the lewis dot structure of Carbon Dioxide or CO2?
There are 4 lone pairs of electrons present in the carbon dioxide molecule
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Answer:
Explanation:
Carbon dioxide, CO2
Each oxygen contributes 2 electrons - 1 for each bond. That means there are a total of 8 electrons around the carbon, in 4 pairs. Because there are 4 bonds, these are all bond pairs.
