Answer:
Postulates of Dalton's Atomic Theory:
1) Atoms can neither be created nor destroyed.
2) During chemical reaction, atoms combine or separate or re-arrange. They combine in simple ratios.
3) All elements are composed of the indivisible particles called atoms.
4) Atoms of a particular element are identical. They have the same mass and volume.
Postulates of modern atomic theory:
1) All matter is composed of atoms.
2) Atoms consist of protons, electrons and neutrons.
3) Atoms of an element may differ in masses. (as in isotopes)
4) The ratio in which elements combine may not be simple.
Similarities:
1) All elements/matter are/is composed of atoms.
2) Atoms can neither be created nor destroyed.
3) During chemical reactions, atom combine or separate or rearrange.
Differences:
1) Dalton's theory said that atoms are indivisible particles but modern theory denies it and calls atom a divisible particle consisting of sub-atomic particles, protons, electrons and neutrons.
2) Dalton's theory said that atoms of the same element have same mass and volume but according to modern theory, it is said that atoms of the same element can differ in mass (as in isotopes).
3) Dalton said that atoms combine in simple ratio but modern theory denies it.
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Hope this helped!
~AH1807Suppose it takes 5 minutes for half of your sample to radioactively decay. If you started with 80 atoms, and have only 5 radioactive atoms left, how many half-lives have occurred?
What is empirical evidence
A retest of experimental results to make them reliable
Knowledge gained by observation or measurement
A prediction of test results before an experiment
A conclusion derived from evidence and logical reasoning
why is polystyrene soluble in acetone and not water
Polystyrene and acetone are not soluble in water because they are non-polar substances.
A polar substance is a substance that has opposite charges on two ends of the molecule. In polar molecules, a dipole moment exists in the molecule and accounts for its interaction with water.
Water is a polar solvent. It can only dissolve polar molecules. Since polystyrene and acetone are both non-polar substances, polystyrene dissolves in acetone and not in water.
This agrees with the principle in chemistry that like dissolves like.
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with increasing altitude, air density also increases... true or false
Answer:
false
Explanation:
What is the charge of Cl2?
Answer:
Cl2 does not have any charge
Explanation:
But when it is present in its ionic form then chlorine have -1 charge on it. But charge on chlorine varies from -1 to +7
WWE Roman reigns vs john cena summerslam 2021 who won?
Answer:Reigns then hit two Superman punches and a spear to score the pinfall. Result: Roman Reigns defeated John Cena via pinfall to retain the title.
Explanation:
Answer: Roman Reigns I hope this helps
Explanation:
Eleven matches were contested at the event, including one match on the Kickoff pre-show. In the main event, Roman Reigns defeated John Cena to retain SmackDown's Universal Championship.
• An atom of _________ has an atomic mass of ______ because it has ______ protons and _____ neutrons ?
Answer:
carbon 12 6 6
Explanation:
which of these is chemical property
A mid-ocean ridge separates the Pacific plate and the Nazca plate off the western coast of South America.Which statement best describes the relative motions of these two plates?
Answer:
See below
Explanation:
The two plates are called DIVERGENT which means the two plates are moving away from each other. The separating motion can allow magma to come to the surface creating the mid-ocean ridge.
Pots and pans that are used for cooking are often
made of copper, aluminum, and iron. Explain how metallic bonding makes these
metals suitable for this use.
Cooking materials are made of copper, aluminum, and iron because they contain free, mobile electrons owing to the metallic bond.
Metallic bonding involves a sea of electrons that is bonded to metal cations by electrostatic attraction. The electrons in the metallic bond are free to move around the material.
Because there are free electrons, when the material is heated, the electrons receive energy and move faster, this energy spreads throughout the material by conduction.
Hence, good conductors of heat such as copper, aluminum, and iron are used for cooking materials.
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Allison adds ice cubes to water which is at room temperature. Over time, the ice melts.
Read the statement above. How does adding ice to the room temperature liquid change the average kinetic energy of the particles of the
liquid?
Adding ice to the liquid decreases the average kinetic energy of the particles of the liquid.
The temperature of a substance is defined as a measure of the average kinetic energy of the molecules of the substance. The average kinetic energy of the molecules of a substance is directly proportional to the temperature of the substance.
This implies that if I increase the temperature of a substance, the average kinetic energy of the molecules of the substance increases and vice versa.
Ice is at a lower temperature than water at room temperature. Thus, adding ice to water at room temperature decreases the temperature of the water and consequently decreases the average kinetic energy of its particles.
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What is the mass of 7.4 x 10^15 atoms of nickel (Ni)?
Since we are starting from the number of atoms of Nickel, we need to know two sets of formulas:
mass = moles × molar mass
moles = atoms ÷ Avogadro's Number
⇒ mass = (atoms ÷ Avogadro's Number) × molar mass
mass = [(7.4 × 10¹⁵ atoms) ÷ (6.022 × 10²³ atoms/mole)] × (58.69 g/mol)
= 7.21 × 10⁻⁷ g
The mass of 7.4 x 10^15 atoms of nickel (Ni) is 7.21 × 10⁻⁷ g.Someone answer these both for me
Answer:
a b
Explanation:
I think so take it with a grain of salt
What are epimers?
How are glucose and manose epimers?
Please Help!
Answer:
Epimers are carbohydrates which vary in one position for the placement of the -OH groupExplanation:
they have a specific type of stereoisomers which have multiple stereo center's but differ from one another, they differ from each other by configuring at the c-2" atom . so, they are epimersWhat type of front is created when a warm air mass moves in to replace a
retreating cold air mass?
The type of fron created is a "warm" front.
3. Connect the electron configuration of Columns 6 (Oxygen) and 7 (Fluorine) with the
tendency to gain or lose valence electrons easily and the strength of the tendency for
electronegativity.
Answer:
I DON'T KNOW
Explanation:
I DON'T KNOW
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what is the relationship between chemical and electrical energy
Answer:
Electrochemistry,
Explanation:
Electrochemistry is a branch of chemistry concerned with the relation between electricity and chemical change. Many spontaneously occurring chemical reactions liberate electrical energy, and some of these reactions are used in batteries and fuel cells to produce electric power.
I Hope This Helps!!!!!
Answer:
Electrochemistry, branch of chemistry concerned with the relation between electricity and chemical change. Many spontaneously occurring chemical reactions liberate electrical energy, and some of these reactions are used in batteries and fuel cells to produce electric power.
Someone pls help me I will mark you as brain
Answer:
1st one is the answer water cannot be purified by nature pls add me in brainliest
PLEASE HELPP!!!!
What kind of metal is Cu?
Alkaline Earth Metal
Alkali Metal
Transition Metal
Answer:
transition metal
Explanation:
Answer:
Copper is a Transition metal.
Explanation:
Use the periodic table website! It tells you what kind of metals the elements are and if they are metals or nonmetals.
Website: ptable.com
why is beryllium-8 different from beryllium-9 in terms of the nuclear particles?
Answer:
Beryllium-8 (8Be, Be-8) is a radionuclide with 4 neutrons and 4 protons. It is an unbound resonance and nominally an isotope of beryllium. It decays into two alpha particles with a half-life on the order of 10−16 seconds; this has important ramifications in stellar nucleosynthesis as it creates a bottleneck in the creation of heavier chemical elements. The properties of 8Be have also led to speculation on the fine tuning of the Universe, and theoretical investigations on cosmological evolution had 8Be been stable.
Explanation:
Help me pls I will mark you as brain
Answer:
D. 1, 2, and 3
Explanation:
Is college worth it
Answer:
in my opinion not really
Explanation:
An object has a volume of 2 cm3 and a mass of 4 g. What is the density of the object?
Answer: 2.0 grams per cubic centimeter
Explanation: i had this
the range of all forms of radiant energy is called the
Answer:
I think its electromagnetic spectrum
Answer:
Radiant energy is energy that travels in waves and can travel through space. The sun gives off radiant energy and is important here on earth for many natural processes to occur. The electromagnetic spectrum is the range of all forms of radiant energy from gamma rays to radio waves.
Explanation:
A. Changes can occur to certain chemical properties of the substance, but the overall shape of the substance will remain the same.
B. Changes can occur to certain physical properties of the substance, but the overall shape of the substance will remain the same.
C. Changes can occur to physical properties of a substance, but the chemical composition of the substance remains the same.
D. Changes can occur to chemical properties of a substance, but the chemical composition of the substance remains the same.
Answer:
changes can occur to physical properties of a substance, but the chemical composition of the
substance remain the same.
Answer:
Changes can occur to physical properties of a substance, but the chemical composition of the substance remains the same.
Explanation:
I got 100% on edg quiz 2022
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Question
A student measures the distance between points A and B. The student uses a stopwatch to measure the time taken to travel from point A
to point B. Which equation helps the student to calculate the speed at which an item travels?
Question
O Speed =
Distance
Time
Questio
O Speed =
Time
Distance
Questio
O Speed = Distance x Time
O Speed = Distance + Time
Answer:
Speed = Distance × Time
A× B
what is the percent of phosphorus by mass in phosphoric acid h3po4
Explanation:
% phosphorus by mass
= (mass of phosphorus ÷ mass of phosphoric acid) × 100%
= (30.974 g/mol ÷ 97.994 g/mol) × 100%
= 31.61 %∴ percent of phosphorus by mass in phosphoric acid 31.61%.Meat or fish spoilage is often due to spoilage bacteria which utilize. to grow in population.
glucose and free amino acids.
glucose
free amino acids
sulfides
Answer:
glucose and amino acids
Explanation:
Research the validity of ONE of the following hypnosis claims using reputable sources. (No blogs, social media posts, etc.)
1.Hypnosis can help people stop smoking.
2. Hypnosis can help people with weight loss.
A. To what extent does hypnosis work in regards to these behaviors?
B. Would you recommend them? Why or why not?
C. What sources did you use to find your answers.
Answer:
1. Hypnosis can help people stop smoking.(Yes)
To what extent does hypnosis work in regards to these behaviors?
A study by McNeilly and colleagues found that hypnosis may help quitters to focus on their own resources to curb cigarette cravings. Other researchers have suggested that success rates are caused by the relaxation effects of hypnosis. These might allow people to cope with nicotine addiction and nicotine withdrawal.
Would you recommend them? Why or why not?
I wouldn't recommend it because, The evidence for hypnosis as a successful smoking cessation method is a mixed bag. Some studies have seen high success rates, whilst others are more modest. A review of 59 different trials found that hypnosis is often better than no support at all.( so its a risk)
Explanation:
since we cannot measure to absolute zero, how can we determine what the volume will be at that temperature?
Answer:
We can measure volumes approaching absolute zero and then predict what the volume would be at absolute zero.
Since there is NO molecular motion at absolute zero, the volume of a balloon at absolute zero should be zero.
If you headed to the deepest recesses of intergalactic space, shielded from starlight, the only thing that would heat you up would be the Big Bang's leftover glow: the cosmic microwave background at 2olume.ht v725 K. At that temperature, the balloon would have a volume.
Charles' Law asserts that a gas's volume (V) and temperature (T), which must be expressed in Kelvin, are directly proportional to one another. A change in temperature of one Kelvin unit corresponds to a change in one Celsius degree. Never forget that the value 0 on the Kelvin scale corresponds to -273 or "Absolute Zero."
What will the volume be at absolute zero, and how can we calculate it?Charles's Law, V = a T+ b, is used to calculate absolute zero once the mass measurements are transformed to high and low temperature gas volumes.
The volume of an ideal gas would theoretically be 0 at absolute zero, and there would be no more molecular motion. Actually, above this temperature, all gases condense into solids or liquids.
According to Boyle's Law, gas volume grows as pressure lowers. Charles' Law states that when the temperature rises, the volume of the gas increases.
Gases compress infinitely as the temperature is lowered because there is a linear relationship between temperature and pressure for the majority of gases (see gas laws). The volume of an ideal gas would theoretically be 0 at absolute zero, and there would be no more molecular motion.
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