Answer:
1). Atoms of each element contain a characteristic number of protons. In fact, the number of protons determines what atom we are looking at (e.g., all atoms with six protons are carbon atoms); the number of protons in an atom is called the atomic number.
2) In contrast, the number of neutrons for a given element can vary. Forms of the same atom that differ only in their number of neutrons are called isotopes.
3) Together, the number of protons and the number of neutrons determine an element’s mass number: mass number = protons + neutrons. If you want to calculate how many neutrons an atom has, you can simply subtract the number of protons, or atomic number, from the mass number.
Predict the decay process and write the nuclear equation of Cf- 255
Answer:
curium
−
243
,
252
/
99
Es,
251
/
98
Cf,
214
/
82
Pb
Explanation: Im not very good with this but here ya go!
OOO OOO
Water's strong hydrogen bonds result in which physical properties? Check all that apply.
high boiling point
low boiling point
high specific heat
low specific heat
density of ice being less than that of liquid water
density of ice being greater than that of liquid water
Ensure you write the states of the reactants and products.
• phosphoric acid reacts with magnesium hydroxide
To balance a redox reaction, what must be done?
The ion charge on both sides of the equation must equal zero.
Water must be added to both sides of the equation.
The increase and decrease in oxidation numbers must be balanced.
H+ and OH− must be added to opposite sides of the equation.
To balance a redox reaction, the increase and decrease in oxidation numbers must be balanced.
A redox reaction also called an oxidation- reduction reaction is a chemical reaction in which there is simultaneous gain and loss of electrons.
The species that loses electrons gets oxidized while the species that gains electrons gets reduced. This results in a change of oxidation number. The species that gets reduced decreases in oxidation number and the species that gets oxidized increases in oxidation number.
So, to balance a redox reaction, the simultaneous gain and loss of electrons must be balanced.
Thus, to balance a redox reaction, the increase and decrease in oxidation numbers must be balanced.
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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 molarity of the nitric acid solution if 20.5 mL of a 0.125 M lithium hydroxide solution are needed to titrate a 25.0 mL sample of the nitric acid solution
Answer:: We're asked to find the molar concentration of the NaCl solution given some titration data.
Explanation:
What makes the Earth go around the Sun?
Answer:
Just as the Moon orbits the Earth because of the pull of Earth's gravity, the Earth orbits the Sun because of the pull of the Sun's gravity. ... This happens because the Earth has a velocity in the direction perpendicular to the force of the Sun's pull.
Explanation:
How do ionic and molecular compounds behave in water?
Answer:
When ionic compounds dissolve in water they go through a process called dissociation, splitting into the ions that make them up. However, when you place covalent compounds in water, they typically do not dissolve but form a layer on top of the water.
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.
the size of camphor kept in store house gradually decrease in size after few а days?
Answer:
Because it goes through the process of sublimation.
Explanation:
NEED HELP ASAP WILL GIVE BRAINLIEST
Answer:
First we know that the molar mass of CO2 is 44.01g/mol, and that the sample of CO2 contains 3.408 x 10^21 molecules, and we have to find the mass of that sample.
We know that moles = mass/molar mass, if we rearrange the equation for mass, we'll get:
mass = moles x molar mass
Also, note that the number of atoms/molecules in a sample is the moles of the sample x Avogadro's number (6.02 x 10^23)
If we rearrange the equation for moles, we would get:
moles = molecules of sample/6.02 x 10^23
Plug in the values for the equation above to get the moles:
moles = (3.408 x 10^21)/(6.02 x 10^23)
moles = 0.00566112956 (we're not done yet)
Now that we have the moles and we were already provided the molar mass, we can calculate the mass using the very first equation we rearranged.
mass = moles x molar mass
mass = 0.00566112956 x 44.01
mass = 0.2491g (answered 4 places past the decimal point)
Therefore the sample of Carbon Dioxide has a mass of 0.2491g
Explain why the first ionisation energy of beryllium is higher than the first ionisation
energy of lithium.
Answer:
since the distance between the electron and the nucleus is smaller in B than in Li, the electrostatic nuclear force of attraction experienced by B is higher than the one experienced by Li...this translates to the higher first ionization energy in B than in Li.
Explanation:
i hope it's helping!
The side of a cube is found to be 127.58 mm and its mass is found to be 7.3 kg. Determine the density of this cube in g/mL.
Answer:
3.5154 g/mL
Explanation:
You will need to use the equation Density = Mass/Volume. You are given mm(can be used to find volume) of a cube and kg(mass). Since your answer is in g and mL we should convert it to those sizes. First we want cm so we will divide the 127.58 mm to cm getting 12.758 cm. We want to cube it since we are finding the whole area of a cube( 12.758*12.758*12.758) which will equal 2076.58 cm^3. We know that 1 mL is equal to 1 cm^3, so we can take our 2076.58 cm^3 and label them as mL(which is what we want). Then we know that there are 1000g in 1 kg, so if we multiply the 7.3 kg, we get 7300g. Finally use the equation Density = Mass/Volume to get your answer. 7300g/2076.58mL = 3.5154 g/mL.
Hope this helps!
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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How many atoms are AI(OH)3 ?
Answer:
It has a total of three elements and seven atoms. Another use that aluminum hydroxide has is it treats the symptoms of too much stomach acid. Some examples of what it treats are: upset stomach, heartburn, and acid indigestion.
Explanation:
Atomicity is the no of atoms present in one molecule. Atomicity of Al(OH)3 = 7.
What is the molarity of a NaOH solution when 22.14 mL of 0.105 M oxalic acid is needed to
neutralize 25.0 mL of the base.
The molarity of the NaOH solution required for the reaction is 0.186 M
We'll begin by writing the balanced equation for the reaction
H₂C₂O₄ +2NaOH —> Na₂C₂O₄ + 2H₂O
From the balanced equation above,
The mole ratio of the acid, H₂C₂O₄ (nA) = 1
The mole ratio of the base, NaOH (nB) = 2
From the question given above, the following data were obtained:
Volume of the acid, H₂C₂O₄ (Va) = 22.14 mL
Molarity of the acid, H₂C₂O₄ (Ma) = 0.105 M
Volume of the base, NaOH (Vb) = 25 mL
Molarity of the base, NaOH (Mb) =?MaVa / MbVb = nA/nB
(0.105 × 22.14) / (Mb × 25) = 1/2
2.3247 / (Mb × 25) = 1/2
Cross multiply
Mb × 25 = 2.3247 × 2
Mb × 25 = 4.6494
Divide both side by 25
Mb = 4.6494 / 25
Mb = 0.186 MTherefore, the molarity of the base, NaOH solution is 0.186 M
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why compounds with weak molecular forces are usually gases.
Molecular substances tend to be gases because the intermolecular forces of attraction are comparatively weak. You don't have to break any covalent bonds in order to melt or boil a molecular substance.
The longest intermolecular separation and hence the strongest intermolecular pressure of attraction can be found in the gaseous state of matter.
Although solids' intermolecular interactions were sufficient to maintain themselves in locked places, gases often have weak intermolecular forces that cause them to remain considerably separated. The gases possess greater intermolecular space than solids as a result of these weak forces.
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The gas in a 250. mL piston experiences a change in pressure from 1.00 atm to 2.25 atm. What is the new volume (in mL) assuming the moles of gas and temperature are held constant?
Answer:
111.11 mLExplanation:
Since the moles of gas and temperature are held constant the new volume can be found by using the formula for Boyle's law
[tex]V_2 = \frac{P_1V_1}{P_2} \\[/tex]
where
P1 is the initial pressure
P2 is the final pressure
V1 is the initial volume
V2 is the final volume
From the question
P1 = 1 atm
P2 = 2.25 atm
V1 = 250 mL
We have
[tex]V_2 = \frac{250 \times 1}{2.25} = \frac{250}{2.25} \\ = 111.1111111...[/tex]
We have the final answer as
111.11 mLHope this helps you
Which condition is usually associated with low air pressure systems?
Answer:
clouds and precipitation that minimize temperature changes throughout the day
Explanation:
Which model represents a compound with a 1:2 ratio?
Please explain your answer.
Answer:
D
Explanation:
D is the correct answer due to the fact that they way they are connected has 2 purple atoms and 1 orange one. thus would create a 1:2 ratio with 1 orange atom and 2 purple atoms.
A would create a 2:3 ratio, B wouldn't create a ratio comparable to the others, and C creates a 1:1 ratio with a few purple atoms floating around them, making all of the answers except D invalid.
In the given figures, the name of the model representing a compound with a 1:2 is figure D.
What is molar ratio?Molar ration of any compound gives idea about the ratio of the concentration of given constituents present in that compound.
In the figure A molar ratio is 2:3, in figure B molar ratio of given constituents is not given because each molecule is composed of same types of atoms, in figure C molar ratio of given constitutes particles is 1:1 and in the figure D molar ratio of constituents is 1:2. Because in figure D, two atoms of one element and 1 atom of another element is present.
Hence, figure D is correct option.
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How do molecules work?
A molecule is essentially created by a collection of atoms linked by a network of bonds.
Give reason. When the tip of a plant is cut, it does not grow tall.
Answer: The growth of the plant decides on the presence of plant hormone, auxin which develops in the roots and shoots. Auxins change the rate of elongation in plant cells, controlling how long they become. So, if the tips are removed, there is no auxin made and growth of the plant stops.
What type of material is half-life associated with?
Answer:
Radioactive material
Explanation:
Element X has an electron configuration of 2-8-2. This element will combine with the oxide ion to form a compound with the formula
How many moles of CH, are present in a 13982.87 gram sample of CHg?
If 0.45 mole oxygen gas occupies a volume of 1.5 L, what volumes will 2.0 moles of oxygen gas occupy at the same temperature and pressure?
please don't send YouT8ube link i need a solution
Answer:
1. How many moles of oxygen will occupy a volume of 2.5 liters at 1.2 atm and 25° C? PV = V (1.2 n. 0821) (298) = 123 mols 2.
2.0 moles of oxygen gas will occupy a volume of 6.67 L at the same temperature and pressure.
Moles is a unit of measurement used in chemistry to express the amount of a substance. It is a counting unit that represents the number of particles, such as atoms, molecules, or ions, in a given sample.
One mole of a substance is defined as the amount of that substance that contains Avogadro's number of particles, which is approximately 6.022 x 10²³. This number is based on the concept that atoms, molecules, and ions are extremely small and difficult to count individually, so using moles allows for a more practical and convenient representation of quantities.
Given:
Moles of oxygen gas (initial) = 0.45 mol
Volume of oxygen gas (initial) = 1.5 L
Moles of oxygen gas (final) = 2.0 mol
Volume of oxygen gas (final) = ?
Using the principle of molar volume, we can set up the following ratio:
(0.45 mol / 1.5 L) = (2.0 mol / V)
V = (1.5 L × 2.0 mol) / 0.45 mol
V = 6.67 L
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AgNO3 is a useful chemical that has many applications and can undergo a variety of reactions. In the following examples, balance each equation if necessary and then identify what type of reaction it represents. i. AgNO3 + Cu —>Cu(NO3)2 + Ag ii. AgNO3 —> Ag +O2 + NO2 iii. AgNO3 + KCI —> AgCI + KNO3 iv. Ag+ +I- +Agl
The balance chemical equation and the type of reaction of AgNO₃ and the other compounds can be represented as follows;
2AgNO₃ + Cu → Cu(NO₃)₂ + 2Ag (single displacement )
2AgNO₃ → 2Ag + O₂ + 2NO₂ (decomposition reaction)
AgNO₃ + KCI → AgCI + KNO₃(double displacement reaction)
2Ag + I₂ → 2AgI (synthesis reaction)
AgNO₃ + Cu → Cu(NO₃)₂+ Ag
The balance equation is as follows:
2AgNO₃ + Cu → Cu(NO₃)₂ + 2AgThis is a single displacement (substitution) reaction. The Copper substance displaced silver from it compound.
AgNO₃ → Ag + O₂ + NO₂
The balance equation is represented as follows:
2AgNO₃ → 2Ag + O₂ + 2NO₂The reaction is a decomposition reaction. Silver nitrate was decompose to it individual constituent.
AgNO₃ + KCI → AgCI + KNO₃
The balance equation is represented as follows:
AgNO₃ + KCI → AgCI + KNO₃The reaction is a double displacement reaction. The anions and cations of two different compound switch places, forming two entirely different compounds.
Ag + I₂ → AgI
The balance equation is as follows:
2Ag + I₂ → 2AgIThe reaction is a synthesis reaction. The individual elements combined to form a compound.
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describe the atomic models above in terms of
a. location of nucleus
b.location of electrons
1 point
Convert 3.79 x 10^24 atoms of sodium to grams.
Answer:
is easy to poiling
Explanation:
also is dificult to melting
PLEASE HELP 100 POINTS
identify the type of chemical reaction:
C6H12 + 9 O2 ---> 6 CO2 + 2 H2O
Answer:
Hexenes + Dioxygen = Carbon Dioxide + Water
The reaction type is combustion.
Its reactants are Hexenes - C6H12 and Dioxygen - O2
its products are Carbon Dioxide - CO2 and Water - H2O
Explanation: This was my yesterdays class