There is about 30 g of Californium-252 left, how much time has elapsed?
You haven't provided two critical pieces of info needed to answer this question. First, what's the half-life of Californium-252, and second, what's the initial amount of Californium-252. Given these two values, you can then set up an exponential equation to find the time elapsed.
A. C5H14
B. C5H12
C. C6H14
D. C6H12
Answer:
C. C₆H₁₄
General Formulas and Concepts:
Chemistry - Atomic Structure
Writing CompoundsExplanation:
To find the molecular formula of the model, you simply count and add up the same elements together.
We see that we have 6 carbons and 14 hydrogens. Therefore our answer is C. C₆H₁₄
Different isotopes of the same element must have a different
Answer:
they must have same atomic number and different atomic mass
Question 7
Anna is rolling a ball down a hill. As the ball rolls, the potential energy is changed to which type of energy?
A chemical energy
B
kinetic energy
С
light energy
D
stored energy
Give equation to show the reaction between Na and the following;H2O,H2,Graphite,O2,Cl2,Pb,NH3
Answer:
Answered below
Explanation:
1) 2Na (s) + 2H2O (l) → 2NaOH (aq) + H2 (g)
2) 2Na (s) + H2 (g) → 2NaH (s)
3) Formula for graphite is C.
Thus;
Na + C → NaC
4) 2Na (s) + O2 (g) → 2Na_2O_2 (s)
5) 2Na (s) + Cl2 (g) → 2NaCl (s)
6) Na + Pb → NaPb
7) Na (s) + NH3 (g) → NaNH2 (s) + H2 (g)
Question 10 of 25
Consider this reaction:
Mg(s) + 2H2O(1) ► Mg(OH)2(s) + H2(g)
What is the oxidation state of Mg in Mg(OH)2(s)?
A. +2
B. - 2
C. +1
D. 0
The oxidation number of Mg in Mg(OH)₂ is +2.
Hence, Option A is correct answer.
What is oxidation number?The oxidation state, or oxidation number, is defined as the hypothetical charge of an atom if all of its bonds formed with different atoms were fully ionic. It indicates the degree of oxidation of an atom in a chemical compound. Conceptually, the oxidation state may be negative, positive or zero.
Oxidation number of OH = -1
Let us suppose the oxidation number of Mg = x
Charge on compound = 0
We can write
x + 2(-1) =0
x-2=0
x = 2
Thus from the above solution we concluded that The oxidation number of Mg is +2.
Hence, Option A is correct answer.
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Whats the difference between an atom and an ion?
An atom is the fundamental unit of matter and it contains an equal number of protons and electrons in its nucleus which makes it electrically neutral. An ion however, is an atom containing an unequal number of protons and electrons which means it will either carry a net positive charge or negative charge depending on whether there are more electrons or protons.
Answer:
atoms are neutral or they have equal number of proton and electron but ions can be cation(positively charged) or anion(negatively charged) based on the number of electron the atom lose and gain respectively
Why do you think it is important that the procedures of a science lab report be written so that another person could perform your experiment exactly the way you performed it?
Answer:
for example the company has been in the United kingdom for women who have a lot to say it is not the only one that has the best of
Explanation:
get a little bit more of the year and
Answer:
for example the company has been in the United kingdom for women who have a lot to say it is not the only one that has the best of
Explanation:
The largest Alkali metal is ?
Answer:
cesium is the largest alkali metal.
Explanation:
Answer:
Cesium
Explanation:
Cesium is the largest atom among alkali metal.
AP Chemistry
25.5 g of methane burns in the combustion reaction below. How much water is produced in this reaction? CH4 + 202 -- CO2 + 2H20
A. 22.69
B. 57.39
C. 510g
D. 3.18 9
Answer:
B
Explanation:
CH4 + 2 O2 → CO2 + 2 H20
12 + I X 4 → → 2 ( I X2 + 16 )
16 → → 36
25, 5 → → ?
amount of H2O = 36 X 25,5 / 16 = 57. 39
One mole or 16 g of methane gas reacts with excess oxygen to give 2 moles or 36 g of water. Then, the mass of water produced from 25.5 g of methane is 57.3 g.
What is combustion?Combustion is the reaction of a gas with the atmospheric oxygen producing water and carbon dioxide. The hydrocarbon gases such as methane, ethane etc easily undergo combustion reaction.
As per the given balanced reaction, one mole of methane gas CH4 produces two moles of water.
molar mass of methane = 16 g/mol
molar mass of water = 18 g/mol
mass of 2 moles of water = 36 g.
Hence, 16 g methane gas produce 36 g of water.
The mass of water produced from 25.5 grams of methane gas is then calculated as follows:
mass of water = 25.5 × 36 / 16 = 57.3 g.
Therefore, 57.3 g of water is produced in this reaction from 25.5 g of methane.
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A 0.0795-g sample of magnesium metal reacts with hydrochloric acid to give 88.5 mL of hydrogen gas at 25 degree C and 766 mm Hg.
Required:
a. Calculate the moles of hydrogen gas produced.
b. Calculate the molar volume of hydrogen gas at STP.
c. What are major sources of experimental error?
Answer:
(a). 0.0037 mol.
(b). 22.42 L
(c). => When the measuring apparatus are not precise.
=> Error due to parallax.
=> Random errors.
Explanation:
Without mincing words let us dive straight into the solution to the question above. So, we are given the following parameters or information which are going to aid in solving this particular Question;
Mass of magnesium given= 0.0795 g, volume of Hydrogen = 88.5 mL = 0.0885 L, temperature = 25 degree C = 273 + 25 = 298K and pressure = 766 mm Hg = 766/760 = 1.00789 atm.
(a). In order to determine the number of moles of Hydrogen atoms,we will be making use of the formula below;
Number of moles = (pressure × Volume)/ gas constant,R × Temperature.
Thus,the number of moles of Hydrogen = 1.00789 × 0.0885 / [( 0.08206 × 298] = 0.0037 mol.
(b). The molar volume at stp can be calculated by using the same formula that was used in (a) above;
Molar Volume at stp = Gas constant,R × temperature/ Pressure = 0.08206 × 273 / 1 atm = 22.42 L.
(c). The major sources of errors are given below:
=> When the measuring apparatus are not precise.
=> Error due to parallax.
=> Random errors.
1. Which groups of the periodic table constitute p-block?
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Answer:
oxidation
Explanation:
the process or result of oxidizing or being oxidized.
hope this helpppppppppppppeddddddd
How many HCl molecules and moles are there in 3.65 grams of
hydrogen chloride at normal conditions?
Answer:
0.6022×10²³ molecules
Number of moles = 0.1 mol
Explanation:
Given data:
Mass of HCl = 3.65 g
Number of molecules = ?
Number of moles = ?
Solution:
Number of moles:
Number of moles = mass/molar mass
Number of moles = 3.65 g/36.45 g/mol
Number of moles = 0.1 mol
Number of molecules:
1 mole of any substance contain 6.022×10²³ molecules
0.1 mol × 6.022×10²³ molecules/ 1 mol
0.6022×10²³ molecules
Which molecule has a structure that is most like aspirin?
O propene
O octyne
O benzene
O butane
Pls pls help me!
The molecule which has a structure that is most like aspirin is benzene.
What is aspirin?Aspirin, also known as acetylsalicylic acid, is a pain reliever, fever reducer, and inflammation reducer.
In the structure of aspirin one aromatic ring is present in which carboxylic group is present and molecular formula of aspirin is written as C₉H₈O₄.
Propene, octyne and butane are aliphatic compounds.Benzene has a common structure with aspirin as they both have aromatic ring in it.Hence benzene has a structure that is most like aspirin.
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How much of a sample remains after five half-Iives have occurred?
1/5 of the original sarmple
1/25 of the original sarmple
1/32 of the original sample
1/64 of the original sample
Answer:
1/32 of the original sample
Explanation:
edgunity got it.
what is the mass in grams of 120 liters at STP oh He gas
The mass of He gas = 21.428 g
Further explanationGiven
120 liters of He gas
Required
the mass in grams
Solution
Conditions at T 0 ° C and P 1 atm are stated by STP (Standard Temperature and Pressure). At STP, Vm is 22.4 liters/mol.
Mol for 120 L :
[tex]\tt \dfrac{120}{22.4}=5.357~moles[/tex]
Mass of He gas(MW=4 g/mol) :
[tex]\tt mass=mol\times Ar\\\\mass=5.357\times 4=21.428~g[/tex]
1. A force of 30N is applied to a screwdriver to pry the lid off of a can of paint. The
screwdriver applies 90N of force to the lid. What is the MA of the screwdriver?
Answer:
120N
Explanation:
Answer:
3
Explanation:
Load / Effort
The effort is 30N and the Load is 90N.
So the MA is equal to 90/30 = 3
which part of the mushroom gathers nutrients from the soil or dead material that the mushroom is decomposing?
Answer:
The Mycelium is usually hidden in the soil, in wood, or another food source. A Mycelium may fill a single ant or cover many acres.
how does increasing the height of an object affect its mechanical energy
Answer:
The amount of work required to raise the TV from point A to point B is equal to the amount of gravitational potential energy the TV gains from its height above the ground. This is generally true for any object ...
How many electrons are there in a chlorine ion?
Answer:
17 for chlorine atom ; 18 electrons for a chlorine ion
please helpppppppppppp
Answer:
The answer would be cation
Explanation:
Answer:
it's an anion
if it has more electrons than protons, then it has a negative net charge making it an anion
12. An electron moving around the nucleus possesses two types of energies which are
Answer:
they bonding
Explanation:
dfffffffffffffff
which statement is right please explain giving brainliest
Answer:
D
Explanation:
Because if I said its 35 degrees outside that has nothing to do with climate maybe if I said its usually 35 degrees in the month of December but just saying what temperature it doesn't tell you anything about climate
Well, the definition of climate is the weather conditions prevailing in an area in general or over a long period so I don't really know
So maybe it is d
Answer:
B
Explanation:
Weather refers to the short-term conditions of the lower atmosphere, such as precipitation, temperature, humidity, wind direction, wind speed, and atmospheric pressure. It could be sunny, cloudy, rainy, foggy, cold, hot, windy, stormy, snowing … the list goes on.
If the world suffered a huge catastrophic event (an event causing great and often sudden damage or suffering; a disaster) that wiped out almost all the organisms. Who would have the best chance of repopulation the world with living organisms, an asexual reproducing organism or a sexually reproducing organism? Explain your answer.
Answer:
An asexually reproducing organism would have the best chance of repopulating the world.
Explanation:
Sexual reproduction is a method of reproduction that involves two parents and the formation and subsequent fusion of male and female gametes during fertilization. On the other hand, In asexual reproduction, only one parent is involved and produces offspring by making copies of itself through various methods such as binary fusion, budding and vegetatively.
In a case of a catastrophic event that wiped out almost all organisms, an organism that reproduces asexually have a greater chance of repopulating the world because of the following advantages in reproducing asexually:
1. Only one parent is needed, therefore reproduction is easier.
2. It isaves time and energy. Since almost all organisms have been wiped out, there is a lesser likelihood of finding a compatible mate, so reproducing asexually will give the organism a better chance.
3. It occurs at a very fast rate; much faster than sexual reproduction
4. The population can increase very quickly and colonization of new habitats is much easier.
All these advantages will give the esexually reproducig organism a fairer chance to repopulate the world.
Guys please help me I have a final exam
a 20.0 l tank of co2 contains 68.0 grams of gas at 500.0 kpa of pressure what is the temperature of the tank ?
Explanation:
ok that is ans k............
The temperature of the 20 L tank containing 68 g of carbon dioxide, CO₂ at 500 KPa is 778.5 K
How to determine the mole of CO₂Mass of CO₂ = 68 gMolar mass of CO₂ = 44 g/mol Mole of CO₂ =?Mole = mass / molar mass
Mole of CO₂ = 68 / 44
Mole of CO₂ = 1.545 moles
How to determine the temperature Volume (V) = 20 L Number of mole (n) = 1.545 moles Pressure (P) = 500 KPa Gas constant (R) = 8.314 LKPa/Kmol Temperature (T) =?Using the ideal gas equation, the temperature of the gas can be obtained as follow:
PV = nRT
Divide both side by nR
T = PV / nR
T = (500 × 20) / (1.545 × 8.314)
T = 778.5 K
Thus, the temperature of the tank is 778.5 K
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For doping silicon with boron, silicon specimen was kept in gaseous atmosphere containing B2O3 that maintained the B concentration at the surface of Si specimen at the level of 3*10^26 boron atoms/m^3. The process was carried out at 1100 degrees C. The diffusion coefficient of B in Si at 1100 degrees C is 4*10^-13 cm^2/s. Calculate the concentration of B at the depth of 10^-4 cm from the surface after 130 minutes of diffusion at 1100 degrees C
Solution :
From Fick's law:
[tex]$\frac{D_{AB}}{\Delta z } \times (C_{A1}-C_{A2})=N_a$[/tex]
Mass balance: Exits = Accumulation
[tex]-N_A A = \frac{dm}{dt}[/tex]
[tex]-N_A A = \frac{dVp}{dt}[/tex]
[tex]-N_A A = \frac{dV}{dt}p[/tex]
[tex]-N_A A = \frac{dhA}{dt}[/tex]
[tex]-N_A A = \frac{dh}{dt} \times Ap[/tex]
From the last step, area cancels out and thus leaves :
[tex]-N_A = \frac{dh}{dt} \times p[/tex]
So now we can substitute the [tex]$N_A$[/tex] by the Fick's law
[tex]$\frac{D_{AB}}{\Delta z } \times (C_{A1}-C_{A2})=\frac{dh}{dt} p$[/tex]
Substituting the values we get
[tex]$=\frac{-4 \times 10^{-13}}{0.0001} \times (3 \times 10^{26} - C_{A2}) = \frac{dh}{dt} \times 2.46$[/tex]
[tex]$=-4 \times 10^{-9} \times( 3 \times 10^{26} - C_{A2}) = 0.0001 \times 2.46$[/tex]
[tex]$= -7800 \times 4 \times 10^{-9} \times (3 \times 10^{26}-C_{A2})=0.000246$[/tex][tex]$=-(3 \times 10^{26}-C_{A2}) = 7.8846 \times 100 \times \frac{1}{69.62} \times 6.022 \times 10^{23}$[/tex]
[tex]$C_{A2} = 6.85 \times 10^{28} \ \text{ boron atoms} /m^3$[/tex]
At 25 °C, what is the hydroxide ion concentration, [OH-], in an aqueous solution with a hydrogen ion concentration of
[H+1=4.1 x 10-5 M?
[OH) =
M
The hydroxide ion concentration, [OH-] = 2.439 x 10⁻¹⁰
Further explanationEquilibrium of water and the ions :
[tex]\tt 2H_2O(l)\rightarrow H_3O^+(aq)+OH^-(aq)[/tex]
[tex]\tt Kc=\dfrac{[H_3O^+][OH^-]}{H_2O}[/tex]
Kc[H₂O] is the ion equilibrium constant for water ⇒ Kw.
The product of the concentrations of these ions (H₃O⁺ and OH⁻)at equilibrium at 25°C is 1.0 x 10⁻¹⁴ M
[H₃O⁺] [OH⁻] = 1.0 x 10⁻¹⁴ M = Kw
The hydrogen ion concentration of [H⁺]=4.1 x 10⁻⁵ M, so the hydroxide ion concentration, [OH-] :
[tex]\tt 4.1\times 10^{-5}\times [OH^-]=1.10^{-14}\\\\(OH^-]=\dfrac{1.10^{-14}}{4.1\times 10^{-5}}\\\\(OH^-]=2.439\times 10^{-10}[/tex]
In lonic bonding, atoms
share electrons
are connected by strong electrical forces
lose protons and form ions
stop moving completely
calculate the volume of pure water that used to dilute 100 ml of 12 M NaOH to 4.75 M.
Answer:
152.63 ml.
Explanation:
By proportion to get a 4.75 M solution the volume will be
(12/4.75) * 100 = 252.63 ml
So the answer is 152.63 ml.
molarity=number of moles/volume
First we find the number of moles of NaOH we have the molarity and the volume we transform mililiters in liters 100ml=0.1l
12=n/0.1 n=1.2 moles of NaOH
now we find the volume of the second solution
4.75=1.2/V
V=1.2/4.75=0.252l
0.252-0.1=0.152liters=152ml of pure water used to dilute