Answer:
93.75
Explanation:
In first half life 750×1/2 will remain
In second one half from that remained at the end of first half life will remain
That is 1/2 × 750×1/2
likewise at the end of 3rd half life 1/2 × 1/2 ×750×1/2 remains
at the end of 4th half life 1/2 × 1/2 × 1/2 ×750×1/2 remains
1/2 × 1/2 × 1/2 ×750×1/2 = 93.75 remains.
You can also use the equation
Remainder = X × 1/2^n .
This saves time
n= no. of half lives
X= initial amount
so in this case 1/2^4 × 750 = 93.75
Use the periodic table to identify the number of core electrons and the number of valence electrons in each case below.
Can you please add a picture of the case??
measuring the isotopic composition of atmospheric co2 shows that the burning of fossil fuels has led to _____ co2 levels over the last 200 years.
Answer:
measuring the isotopic composition of atmospheric co2 shows that the burning of fossil fuels has led to the co2 levels over the last 200 years.
Explanation:
pa brainliest po ty
Which of these figures correctly illustrates the nature of the bonding of h2o?.
H2O is composed of two hydrogen atoms and one oxygen atom. The central oxygen atom is sp3 hybridized.
H2O is composed of two hydrogen atoms and one oxygen atom. The oxygen atom is bonded to the two hydrogen atoms at a dihedral angle of 104°. There are two lone pairs on the oxygen atom. The molecule has a bent geometry.
The structure of H2O is shown in the image attached to this answer. The central oxygen atom is sp3 hybridized and the shape of the molecule is based on a tetrahedron owing to its electron pair geometry.
Learn more: https://brainly.com/question/967776
1.The table below lists some of the common ingredients in toothpaste.
What is the name of the ingredient responsible for preventing decay?
Sodium sulfate
Sodium fluoride
Sodium fluorine
Nitrogen fluoride
What physical change happens to atoms and molecules in a solution that is strongly heated in a flame? Is there a phase change? If so, what is it?
When atoms and molecules speed up or slow down, that is a physical change. When they change state from liquid to solid or from gas to liquid, that is a physical change. ... The ions or molecules can still come back together to form the original substance
The physical change which happens to atoms and molecules in a solution that is strongly heated in a flame is;
The atoms and molecules gain energy and their internal energy is increased.If the heat energy is sufficient, there is a phase change and this phase change is from liquid to gas (evaporation).Heating and Phase changesAtoms and molecules which are units of matter when strongly heated in a flame have increased internal energy and would undergo a phase change to a more energetic state of matter which is the gaseous state.
As such, the physical change that occurs in them is. increased internal energy.
Read more on heating and Phase change;
https://brainly.com/question/12168850
calculate the number of atoms in 1009g of neon
This is kind of a pretty easy question:
- In order to get the number of atoms/entities of Neon, you will have to turn that 1009g of Neon into moles
-And then you have to use the moles and calculate it using Avogadro's Number which is 6.02 x 10^23
number of moles = mass/molar mass of element/compound
n = 1009g/20.18g/mol
n = 50 mol
Number of atoms/entities = 50 x (6.02 x 10^23)
Number of atoms in 1009g of neon is 3.01 x 10^25 (scientific notation because its a really long number)
what is the ka for 0.03M Solution of HClO4 for 1.90 PH value.
A) 7.2x10^-3
B) 8.27x10^-3
C) 8.27x10^-4
D) 6.27x10^-4
(I keep getting 5x10^-3 when I round all the values to 2 decimal places but it’s not in the options)
Are all the wax rings melting at the same time?
Answer:yes
Explanation:
this is because the distance doesnt matter
A substance that can behave as either an acid or a base is: anthocyanin a neutral substance an indicator an amphiprotic substance
Answer:
These substances are called amphiprotic. Water, amino acids, hydrogen carbonate ions, and hydrogen sulfate ions are common examples.
Explanation:
A substance is amphoteric (from Greek amphoteros = "each of two") if it can act as an acid or a base.
For example, aluminum hydroxide is amphoteric because it can act as a base and neutralize strong acids.
A sample of gas is at 78.0 oC. You want to change the volume of the gas from 1.60 L to 0.425 L under constant pressure. What must you do to the temperature of the gas
Answer:
the rule is V1/T1= V2/T2
so we convert the T1 from °c to kelvin
78+273.15= 351.15 k
1.60/351.15 = 0.425/T2
4.55 ×10-³ = 0.425/T2
then T2 = 93.40 kelvin
hence, we should decrease the temperature
Help help with the question below
why does reducing solute particle size increase the speed at which the solute dissolves in water .
Because it has less surface area. This can be applied to something like cooking potatoes. Cooking a larger potato will take longer than a small potato.
A sample of gaseous arsine (AsH3) in a 460 mL flask at 332 Torr and 223 K, is heated to 437 K, at which temperature arsine decom- poses to solid arsenic and hydrogen gas. The flask is then cooled to 273 K, at which tem- perature the pressure in the flask is 488 Torr. What percentage of arsine molecules have de- composed?
Answer in units of %.
Answer:
28/95 = 29.,5 % of Arsine decomposed
Explanation:A sample of gaseous arsine (AsH3) in a 460 mL flask at 332 Torr and 223 K, is heated to 437 K, at which temperature arsine decom- poses to solid arsenic and hydrogen gas. The flask is then cooled to 273 K, at which tem- perature the pressure in the flask is 488 Torr. What percentage of arsine molecules have de- composed?
Answer in units of %.
initial pressure 332 Torr initial volume 0.46 L initial temperature 223K
final pressure 488 Torr final volume 0.46 L final 273 K
Torr is 1/760 atm 332 torr = 0.437 atm 488 Torr =0.642 atm
PV = nRT so n=RT/PV
INITIAL n= 0.082 X 223/(0.437)(0.46) = 91 moles
final n= 0.082 X 273 / (.437)(488) = 105 moles
2AsH3----------> 2As + 3H2
x moles of Arsine decomposed to make 1.5 moles of H2
the final number of moles was
(91 -X)+ 1.5 X = 105 moles
91 + 0.5 X = 105
0.5 X = 14
X =28
CHECK
if 28 moles of Arsine , then the container would have
91 --28 + 1.5(28) = 91 +14 =105 check
so 28/95 = 29.,5 % of Arsine decomposed
Your answer
(quit)
polyalchemVirtuoso
Answer:
Explanation:
ADD YOUR ANSWER
Ask maryhobbs about this question...
New questions in Chemistry
in what area of the united states do the fewest people live
Read each step. Then put the steps in order from first to last. Write 1 for the first step, 2 for the second step and so on. 1. Fossils fuels are burn…
When unbalanced forces act on an object that is in motion, the object can: A. change speed, direction, or both. B. only change direction. C. only s…
What is the missing letter in H,J,K,L,M,N,O,P.? And what is the opposite of HATE.? And what is the opposite of ME.? Think about it -,-
what type of reaction is Fe(NO3)3 + 3LiOH = Fe(OH)3 + 3LiNO3
Please answer this quickly. the answers that you find online are not correct. I will mark brainliest if you get it right. NO SPAM!!!!For the reaction …
cuantos gramos de soluto son necesario para preparar 50 ml de Ca(NO3)2 al 4% (w/v)
Calculate the moles of O in 0.182 mole C6H14O. Calculate the number of H atoms in 0.182 mole C6H14O. Calculate the number of C atoms in 0.182 mole C…
When a sulfur atom and an oxygen atom bond to produce substance C, electrons are? a. delocalised b. shared c. transferred
What is oxidation state?
LOAD MORE
Previous
Next
Ask
fork is a metal or nonmetal ?
How many atoms of lithium are there in 18.2mg of lithium? Dimensional analysis only!
Answer:7.25
Explanation:
This is because 18.2 - 7.2 = 11 +7.2 = 18.2
How do you produce a buffer.
Answer:
Buffers can be made from weak acids or base and their salts.
Explanation:
hope this helps!
(if not tell me in the comments and i will try to help you!)
Answer:
Buffers are made by adding a strong acid or base to a weak acid or base.
Explanation:
how many outer boundaries does a animal cell have
Answer:
The plasma membrane.
Explanation:
membrane, in biology, the thin layer that forms the outer boundary of a living cell or of an internal cell compartment. The outer boundary is the plasma membrane, and the compartments enclosed by internal membranes are called organelles.
Que pasa si a una taza de arena le pongo espuma y lo agito por 10 minutos?
Answer:
Conversion of energy
Explanation:
Shaking the sand is a form of kinetic energy. The friction of the sand particles rubbing against each other converts the kinetic energy to heat energy. Some of the kinetic energy also converts into the energy of sound waves, which you can hear while you shake the sand.
Silver, Chromium and Copper are these type of elements _____
Answer:
Group 11
Explanation:
Group 11, by modern IUPAC numbering, is a group of chemical elements in the periodic table, consisting of copper (Cu), silver (Ag), and gold (Au).
Answer:
silver, chromium and copper are metal type of element
Filling Air Bags Automobile air bags produce nitrogen gas from the reaction:
a. If 2.25 g of NaN3 reacts to fill an air bag, how much P–V work will the N2 do against an external pressure of 1.00 atm given that the density of nitrogen is 1.165 g/L at 20°C?
b. If the process releases 2.34 kJ of heat, what is ∆E for the system?
(a) The work done by the nitrogen against external pressure is 126.66 J.
(b) The change in the internal energy of the system is -2,466.66 J.
The given parameters:
Mass of the compound, = 2.25 gExternal pressure, P = 1.0 atm = 101325 PaDensity of Nitrogen gas, ρ = 1.165 g/LTemperature of the Nitrogen gas, T = 20⁰CThe molar mass of the given compound is calculated as follows;
NaN₃ = 23+ (14 x 3) = 65 g/mol
65 g -------------- 42
2.25 g ------------- ?
[tex]= \frac{2.25 \times 42}{65} \\\\= 1.45 \ g[/tex]
The volume of the nitrogen gas is calculated as follows;
[tex]\rho = \frac{m}{V} \\\\V = \frac{m}{\rho} \\\\V = \frac{1.45}{1.165} \\\\V = 1.25 \ L[/tex]
[tex]V = 0.00125 \ m^3[/tex]
The work done by the nitrogen against external pressure is calculated as follows;
[tex]W = PV\\\\W = 101325 \times 0.00125\\\\W = 126.66 \ J[/tex]
The change in the internal energy of the system is calculated by applying first law of thermodynamics as follows;
[tex]\Delta E = Q - W\\\\\Delta E = (-2,340) - (126.66)\\\\\Delta E = -2,466.66 \ J[/tex]
Learn more about first law of thermodynamics here: https://brainly.com/question/2965070
Batteries allow us to store energy for when it’s needed, such as starting a car engine or jump-starting another car whose battery has lost its charge. But batteries cannot operate without chemical reactions. What kind of energy do you think is stored in the substances within the battery?
Answer:
Chemical energy
Explanation:
I hope this helped you!
Batteries store the energy in the form of chemical energy that chemical energy is converted into electrical energy. Chemical energy is used to stored in the substances within battery.
What is electrochemical energy ?The conversion of chemical energy into electrical energy or vice versa is called as electrochemical energy . This includes reactions transferring electrons, redox reactions .
Redox reaction in which reduction and oxidation takes place simultaneously. Reduction, when a substance receives one electron. Oxidation when a substance gives away one electron.
A battery is a device that stores chemical energy and converts it to electrical energy. The chemical reactions in a battery involve the flow of electrons from one material (electrode) to another, through an external circuit.
Thus, chemical energy is used to store in the substance within battery.
To learn more about electrochemical energy refer the link below;
https://brainly.com/question/25551241
#SPJ2
Determine the wavelength of the light absorbed when an electron in a hydrogen atom makes a transition from an orbital in which n=2n=2 to an orbital in which n=7n=7.
Answer:
The expression for the wavelength of radiation is,
λ
1
=R(
n
1
2
1
−
n
2
2
1
)
Substitute values in the above expression,
λ
1
=109677×(
2
2
1
−
4
2
1
)=109677×(
4
1
−
16
1
)=109677×(
64
12
)
λ=4.86×10
−5
cm=486×10
−9
m=486nm.
The line belongs to bluish green colour.
Solutions
Which statement is true of pure substance
1. They may contain one type of atom or one type of molecules.
2.they can only contain one type of molecules.
3.they can contain different types of atoms and molecules.
4.they can only contain one type of atom
This is science btw
Answer:
4
Explanation:
cuz pure substance contain one type of atom,molecule,or cpd.
2 is true but it have wrong grammar,if it contain only one type it must be^^molecule^^
How could the student obtain zinc chloride solution from the reaction mixture when all the hydrochloric acid has reacted?
Answer:
zinc oxide is only sparingly soluble in water so best option is to add zinc oxide to diluted hydrocrolic acid
When all the hydrochloric acid (HCl) has reacted, the student can obtain zinc chloride (ZnCl) solution from the reaction mixture by adding ZnO to diluted HCl.
What is a mixture?
A mixture simply refers to a combination of two (2) or more substances or chemical compounds that are present in varied proportion, and they can be visibly seen with na-ked eyes.
In this scenario, the student can obtain zinc chloride (ZnCl) solution from the reaction mixture when all the hydrochloric acid (HCl) has reacted by adding zinc oxide (ZnO) to diluted hydrochloric acid (HCl) because it's sparingly soluble in water.
Read more on mixture here: https://brainly.com/question/24647756
#SPJ2
Hurry Answer for a Brainlist
Answer:
The most accurate and percise player was Josh
26 Milkweed contains a poison known as cardenolides. Monarch butterflies eat the milkweed plant and hold on to this toxic compound. The
chemical formula for cardenolides is shown below.
CH18C20H15CHCO2
Problem
How many atoms of each element are in one molecule of cardenolides?
A
42 carbon atoms, 23 hydrogen atoms, and 2 oxygen atoms
B
20 carbon atoms, 33 hydrogen atoms, and 2 oxygen atoms
с
34 carbon atoms, 43 hydrogen atoms, and 2 oxygen atoms
D
23 carbon atoms, 34 hydrogen atoms, and 2 oxygen atoms
please help ASAP !!
Cardenolides, with the chemical formula CH₁₈C₂₀H₁₅CHCO₂ have (D) 23 carbon atoms, 34 hydrogen atoms, and 2 oxygen atoms.
Milkweed contains a poison known as cardenolides. The chemical formula for cardenolides CH₁₈C₂₀H₁₅CHCO₂.
The subscripts in the formula represent the atomicities, that is the number of atoms of each element in each part of the formula.
We can calculate the total number of atoms of each element by adding its atomicities.
Carbon atoms[tex]C = 1 + 20 + 1 + 1 = 23[/tex]
Hydrogen atoms[tex]H = 18 + 15 + 1 = 34[/tex]
Oxygen atoms[tex]O = 2[/tex]
Cardenolides, with the chemical formula CH₁₈C₂₀H₁₅CHCO₂ have (D) 23 carbon atoms, 34 hydrogen atoms, and 2 oxygen atoms
Learn more: https://brainly.com/question/13348838
Draw the alkyne formed when 1,1‑dichloro‑3‑methylbutane is treated with an excess of a strong base such as sodium amide. Omit byproducts. (give the neutralized alkyne product, not the acetylide salt. ).
This problem is asking for the major alkyne product that is formed when 1,1‑dichloro‑3‑methylbutane reacts with sodium amide (NaNH₂) ignoring any byproduct.
Thus, we can firstly say that such reaction of an alkyl halide with a strong base such as sodium amide is able to remove the halogen-based substituents and hence form insaturations in the form of double or triple bonds depending on the degree of substitution.
For instance, if one halogen substituent, then an alkene will be formed; but if two, then an alkyne (like this problem).
In such a way, as shown on the attached figure, the product will be 3-methylbutyne due to the loss of two chlorine substituents.
Learn more:
https://brainly.com/question/9620187https://brainly.com/question/14282000Add 2 teaspoons of baking soda and 2 teaspoons of citric acid to the foam cup. Add the half cup of water to the cup and stir. What is the temperature?
Answer:
Test for carbon dioxide gas.
The reaction between baking soda and citric acid will form sodium ions, citric acid ions, carbon dioxide gas, and water. So all you have to do is add the gas produced (by gas displacement method or something) and test whether the gas is carbon dioxide, with lime water or other methods like hydrogencarbonate indicator. Hope this helped!
Explanation:
Answer:
depends on amount, but the reaction's endothermic (meaning its cold, absorbs heat from surroundings)
I hope it helps.
identify ALL equations that involve Pressure(Minimum 2)
Answer:
p=F/A.Explanation:
Which liquid will evaporate more rapidly? Explain your answer in terms of intermolecular forces
acer