After careful consideration your answer is...
Leucippus and Democritus
*Hope I helped*
~Alanna~
Answer:
The first theories of matter were put forward by Empedocles in 450 BC, he proposed that all matter was composed of four elements - Earth, air, fire and water. Later, Leucippus and Democritus suggested matter was made up of tiny indestructible particles continuously moving in empty space.
Explanation:
NEED ASAP WILL GIVE BRAINLIST
Answer:
It have 31 electrons
It have 31 electrons
What is the process of solar nuclear fusion?
Answer:
base sa research po
Explanation:
In the core of the Sun hydrogen is being converted into helium. This is called nuclear fusion. It takes four hydrogen atoms to fuse into each helium atom. During the process some of the mass is converted into energy.
Answer:
Hydrogen atoms are fused into deuterium, then helium-3, then helium-4, each step giving off large amounts of energy.
Explanation:
Because that's how it works :D
is a physiologist. Which would most likely be the main focus of her studies?
how atoms bond to form different kinds of matter
how subatomic particles interact and make up atoms
how certain molecules affect the function of the human heart
how the structure of the human brain may differ between humans
what is the true of lewis base
Answer: To answer your question of what is true of a lewis base, it is true that a lewis base donates electron pairs.
Explanation: A Lewis base is any substance, such as the OH- ion, that can donate a pair of nonbonding electrons. A Lewis base is therefore an electron-pair donor.
(QUICK)
What is the percent yield if the actual yield is 1.5g and the theoretical yield is 4.5g?
Answer:
33.3% (depending on how many significant figures you need)
Explanation:
Actual yield divided by theoretical yield times 100%
Select the correct answer. What does the kinetic theory state about the relationship between the speed and temperature of gas molecules? A. As the temperature increases, the speed of gas molecules remains constant. B. As the temperature increases, the speed of gas molecules decreases. C. As the temperature increases, the speed of gas molecules increases. D. As the speed of gas molecules increases, the temperature becomes constant. E. As the temperature decreases, the speed of gas molecules increases.
Answer:
C. As the temperature increases,the speed of gas molecules increase.
what is the mass number of an atom that has six protons. six electrons, and eight neutrons?
Mass number is the sum of the total number of nucleons (neutrons + protons) present in the atom.
Mass number = Protons + Neutrons
Mass number = 6 + 8
Mass number = 14
_______
Hope it helps ⚜
What is the molecular geometry if you have a double bond, a single bond and 1 lone pair around the central atom?
Answer:
4 pairs are needed for the bonds, leaving 1 lone pair. Each double bond uses 2 bond pairs and can be thought of as a single unit. There are 2 double bond units and 1 lone pair, which will try to get as far apart as possible - taking up a trigonal planar arrangement.
Which of these is a balanced chemical equation?
How are oxidation-reduction reactions related to how you use energy?
Answer:
In oxidation reduction reactions, one species gets reduced by taking on electron(s) and another species gets oxidized by losing electrons. The movement of electrons can be used to do work. ... The electron flow can be run through a wire and these electrons can be used to do work (like run a battery). Hope this helps.
the sequence of stages an organisms go through from one generation to the next lace where an organism lives is called in
Answer:
A life cycle is the sequence of stages an organisms goes through from one generation to the next. Organisms that reproduce sexually can have different types of life cycles, such as haploid or diploid life cycles.
Why are naphthalene ball used to protect clothes from insects? How does it gradually decrease and ultimately disappear?
A team of scientists is conducting tests to measure the boiling point of a liquid using a thermometer in the liquid. The team is
then recording the temperature where the liquid changes from a liquid to a gas rapidly. After 100 trials, the results are 5 degrees
below the expected results. Which next step is most reasonable? (1 point)
O checking the calibration of the thermometer to ensure that it is giving accurate readings
O assuming that the new results are incorrect
O assuming that the previous measurements are incorrect
O checking the insulation of the apparatus to find out if heat is escaping
The most reasonable step to take will be to check the calibration of the
thermometer to ensure that it is giving accurate readings.
Experiments which are done to be give the same results under standard
conditions. Common causes of incorrect results during the analysis of
boiling point of substances include heating the substance too rapidly or
the thermometer not being properly calibrated.
The thermometer is used to measure the temperature and so must be
properly calibrated to give accurate readings.
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describe an experiment that would show that intramolecular forces (attractions between atoms within molecules) are stronger than intermolecular forces (attractions between molecules).
Answer:
Molecules don’t have to collide with each other in order to experience intermolecular forces.
Molecules with permanent dipoles, held in fixed orientation, such as water molecules in the solid state (ice), interact with a potential proportional to the inverse cube of distance. This intermolecular force always exists, no matter how far apart the molecules are; every water molecule interacts with every other water molecule. However, because it diminishes rapidly with distance, it tends to only be important at short distances. (In contrast, the potential between two ions goes as 1/r, and that between an ion and a dipole goes as 1/r^2.)
The van der Waals forces, of which London dispersion forces are the most important, are described by a potential proportional to the inverse sixth power of distance. Theoretically, those forces are always operating between any two atoms or molecules, but again, only become important at short distances.
Explanation:
hope this helps
1) Which statement best describes the usefulness of a model to investigate molecules at the microscopic level?(1 point)
A model’s usefulness depends on whether direct observations of phenomena can be made.
All models are useful.
A model’s usefulness depends on the accuracy of its predictions.
Models are not useful at all.
2) Which scientist contributed to molecular theory by explaining that gas pressure is caused by the impact of gas molecules on surfaces?(1 point)
Daniel Bernoulli
Amedeo Avogadro
John Dalton
Robert Boyle
3) Which term did Avogadro create?(1 point)
molecule
microscope
kinetic energy
atom
4) Which statement best describes the development of theories that connected microscopic and macroscopic phenomena?(1 point)
It took several hundred years for scientists to develop current theories, and they are essentially concrete.
It only took a few decades for scientists to develop current theories, and they are still being revised to this day.
It only took a few decades for scientists to develop current theories, and they are essentially concrete.
It took several hundred years for scientists to develop current theories, and they are still being revised to this day.
5) How can the results of experiments investigating the relationship between microscopic and macroscopic phenomena affect a model of molecular theory?(1 point)
Consistent results support the validity of the model, while inconsistent results require throwing out the model entirely.
Consistent results require throwing out the model entirely, while inconsistent results support the validity of the model.
Consistent results support the validity of the model, while inconsistent results indicate the need to modify the model.
Consistent results indicate the need to modify the model, while inconsistent results support the validity of the model.
Answer:
1. A model’s usefulness depends on the accuracy of its predictions.
2. Daniel Bernoulli
3. molecule
4. It took several hundred years for scientists to develop current theories, and they are still being revised to this day.
5. Consistent results support the validity of the model, while inconsistent results indicate the need to modify the model.
Explanation:
The discovery that macroscopic and microscopic phenomena are connected took several hundred years.
A model is a representation of a real life system that serves as a tool for predictions and explanation. Since models serve a predictive purpose, a model’s usefulness depends on the accuracy of its predictions.
The pressure of a gas is caused by the collision of gas molecules with the walls of the container. This was established by the scientist called Daniel Bernoulli.
Avogadro was able to create the term molecule to describe a substance that has independent existence. The discovery that macroscopic and microscopic phenomena are connected took several hundred years. It took several hundred years for scientists to develop current theories, and they are still being revised to this day.
The results of experiments investigating the relationship between microscopic and macroscopic phenomena affect a model of molecular theory in the sense that consistent results support the validity of the model, while inconsistent results indicate the need to modify the model.
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In a Lewis Diagram for fluorine, are the two electrons given to the other fluorine atom, taken by the other fluorine atom, or shared between the fluorine atoms?
How many ml of a 2.903 M NaOH solution are needed to produce 500.0 ml of a 0.3344M solution?
Answer:
57.6ml
Explanation:
Using dilution formula
C1V1 = C2V2
C1 = 2.903 M, V1 = ? , C2 = 0.3344 M , V2 = 500ml
2.903 × V1 = 0.3344 × 500
V1 =( 0.3344 × 500)/ 2.903
= 57.5956
≈ 57.6ml
What does lowercase v represent in this formula?
Which of the following expresses the value 300,000,000 in correct scientific notation?
Group of answer choices
3 x 108
0.3 x 10-9
3 x 10-8
0.3 x 109
Answer:
3 x 10^8
Explanation:
What is the volume of HCl (r= 1.17 g / cm ^ 3, omega = 36 \%) required to precipitate silver in the form of AgCl from 2, 000 g of an alloy containing 22% by weight of Ag, if used 1.5 times the amount of precipitating reagent?
The volume of precipitating reagent, HCl required to precipitate silver in the form of AgCl from 2,000 g of an alloy containing 22% by weight of Ag is 0.530 L
In order to determine the volume of precipitating reagent, HCl required to precipitate silver in the form of AgCl from 2,000 g of an alloy containing 22% by weight of Ag, the following steps are followed:
Step 1.
The concentration of the HCl solution is calculated using the formula:
Molarity = percentage * specific gravity * 1000 cm³ / molar mass * 1 LPercentage purity of HCl = 36% = 0.36
specific gravity, r = 1.17 g/cm³
molar mass of HCl = 36.5 g/mol
Concentration of HCl = 0.36 * 1.17 * 1000 / 36.5 * 1
Concentration of HCl = 11.53 mol/L
Therefore, 1 L of HCl solution contains 11.53 moles of HCl
Step 2:
The equation of the dissociation of HCl solution is given below:
HCl (aq) ------> H⁺ (aq) + Cl⁻ (aq)1 mole of HCl produces 1 mole of Chloride ions, Cl⁻
Equation of reaction between Silver in the alloy and HCl is given as follows:
Ag (s) + H⁺Cl⁺ (aq) -----> AgCl (s)A white precipitate of AgCl is formed but hydrogen gas is not formed as Silver is a less reactive metal.
1 mole of HCl produces 1 mole of Cl⁻ which reacts with 1 mole of Ag to produce 1 mole of AgCl precipitate.
Step 3: Determine the mass and number of moles of silver in the alloy
Percentage of silver in the alloy = 22% = 0.22Mass of silver in 2000 g alloy = 0.22 * 2000 g
Mass of silver in 2000 g alloy = 440 g
Number of moles of silver in 440 g of silver is determined using the formula below:
number of moles = mass / molar massmolar mass of silver = 108 g/mol
number of moles of silver = 440 /108
number of moles of silver in the alloy = 4.074 moles
Step 4: Calculate the volume of HCl required
Since 1 mole of Cl⁻ ions react with 1 mole of Ag; 4.074 moles of Cl⁻ ions will be required to react with 4.074 moles of Ag.
1 L of HCl solution contains 11.53 moles of Cl⁻
Volume of HCl solution that contains 4.074 moles of Cl⁻ = 4.074 * 1L/11.53
Volume of HCl that contains 4.074 moles of Cl⁻ = 0.353 L
Since 1.5 times the amount of precipitating reagent HCl is required, volume of HCl required = 1.5 * 0.353 L
Volume of precipitating reagent HCl required = 0.530 L
Therefore, the volume of precipitating reagent, HCl required to precipitate silver in the form of AgCl from 2,000 g of an alloy containing 22% by weight of Ag is 0.530 L
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As an electron in an atom moves from a higher energy state to a lower energy state, the atom
A
becomes a negative ion
В.
becomes a positive ion
С.
releases energy
D.
absorbs energy
Answer:B
Explanation:
Industrial chemists have to understand the chemistry of oxides.
For example, silicon dioxide is used in glass making and carbon monoxide is used in the
extraction of iron from iron ore.
(i) Explain how burning carbon in air can lead to the formation of carbon monoxide.
(2)
(ii) Write the balanced equation for the reaction between silicon and oxygen.
(2)
Answer:
carbon monoxide can be formed due to incomplete combustion of carbon due to insufficient oxygen supply
2C+O2___2CO
Si+O2____SiO2
8. Which property is used to determine the degree of polarity between two bonded atoms? A) density B) electronegativity C) pressure D) temperature
Answer:
I think B) electronegativity is the correct answer.
Electronegativity is the property which is used to determine the degree of polarity between two bonded atoms. Therefore, the correct option is option B.
What is polarity?Polarity is the dispersion of electrical charge over the atoms linked by a chemical bond. Bonds between identical atoms, such as H2, are electrically homogeneous in the sense that both hydrogen atoms are electrically neutral, but bonds between different atoms are electrically inequivalent.
Electronegativity is the property which is used to determine the degree of polarity between two bonded atoms. The relative electronegativities of the elements determine the polarity of a bond. Electronegativity is the ability of an element's atom to attract electrons to itself when it is part of a compound.
Therefore, the correct option is option B.
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50 PTS!!!!! Please answer without links!
What type of chemical reaction happens with Aerobic Cellular Respiration?
Synthesis, decomposition, single displacement, double displacement, or combustion.
calculate the molar mass for each of the following compounds 7. PbSO
8. Ca(OH)2
9. Na3PO4
10. (NH4)2CO3
11. C6H12O6
12. Fe3(PO4)2
13. (NH4)2S
14. Zn(C2H3O2)2
Answer:
Fe3(PO4)2
Explanation:
calculate the molar mass for each of the following compounds 7. PbSO
8. Ca(OH)2
9. Na3PO4
10. (NH4)2CO3
11. C6H12O6
12. Fe3(PO4)2
13. (NH4)2S
14. Zn(C2H3O2)2
What you see as you look up at the night sky depends on the weather, the time of year, your location, and how dark your surroundings are. The
---
and stars are the celestial objects most people can see in the night sky.
the [moon] and stars are what most people see.
How are oxidation-reduction reactions related to how you use energy?
Answer:
In oxidation reduction reactions, one species gets reduced by taking on electron(s) and another species gets oxidized by losing electrons. They also flow by a wire
Explanation:
Polyvalent ions are
1) Anions with variable charges
2) Cations from columns 3 to 12
3) Ions that can be positive or negative
Gold has a specific heat of 0.126 J/g.C. Copper has a specific heat of 0.386 J/g C. Which of the two metals would require more
heat energy to raise the temperature of the same weight of metal by 10.5C?
Answer:
The copper, because its specific heat is higher, meaning it takes more heat (Joules) per gram to raise the temperature 1 degree Celsius.
Explanation:
Why do thermistors increase in conductivity when heated? What happens in normal metals? Explain on the atomic level.
Metal conductivity generally goes down or resistivity goes up with temperature goes up.
