Answer:
1 g
Explanation:
The following data were obtained from the question:
Original amount (N₀) = 32 g
Time (t) = 71.5 days
Half-life of phosphorus (t½) = 14.3 days
Amount remaining (N) =?
Next, we shall determine the rate of disintegration. This can be obtained as follow:
Half-life of phosphorus (t½) = 14.3 days
Decay constant (K) =?
K = 0.693 / t½
K = 0.693 / 14.3
K = 0.0485 /day
Finally, we shall determine the amount remaining as illustrated below:
Original amount (N₀) = 32 g
Time (t) = 71.5 days
Decay constant (K) = 0.0485 /day
Amount remaining (N) =?
Log (N₀/N) = Kt/2.303
Log (32/N) = 0.0485 × 71.5 / 2.303
Log (32/N) = 3.46775 / 2.303
Log (32/N) = 1.5058
Take the antilog of 1.5058
32/N = antilog (1.5058)
32/N = 32.05
Cross multiply
32 = N × 32.05
Divide both side by 32.05
N = 32 / 32.05
N = 0.998 ≈ 1 g
Thus, the amount remaining after 71.5 days is approximately 1 g.
The half-life of a radioactive substance refers to the time taken for the substance to Decay to half of its initial size. Hence, the mass of the substance left after 71.5 days is 1 gram.
Initial mass = 32 g Half life = 14.3 daysAfter 14.3 days ;
32 / 2 = 16 gramsAfter 14.3 × 2 = 28.6 days :
16/2 = 8 gramsAfter 14.3 × 3 days = 42.9 days :
8 / 2 = 4 gramsAfter 14.3 × 4 days = 57.2 days :
4 /2 = 2 gramsAfter 14.3 × 5 days = 71.5 days :
2 /2 = 1 gram.Hence, the mass of the sample left after 71.5 days would be 1 gram.
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The specific heat capacity of a certain type of cooking oil is 1.75 J/(g⋅∘C). What is the amount of heat exchanged when the temperature of 2.76 kg of this oil is cooled from 191∘C to 23 ∘C?
Answer:
Q = -811440 J
Explanation:
Given data:
Mass of oil = 2.76 Kg (2.76× 1000 = 2760 g)
Initial temperature = 191 °C
Final temperature = 23°C
Specific heat capacity of oil = 1.75 J/g.°C
Solution:
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = 23°C - 191 °C
ΔT = -168°C
Q = 2760 g ×1.75 J/g.°C ×-168°C
Q = -811440 J
Negative sign show heat is released.
Which of the following contains the same number of electrons as an atom of neon?
Cl-
Li
Li+
02
Answer:
D. [tex] O^{2-}[/tex]
Explanation:
In Chemistry, electrons can be defined as subatomic particles that are negatively charged and as such has a magnitude of -1.
Valence electrons can be defined as the number of electrons present in the outermost shell of an atom. Valence electrons are used to determine whether an atom or group of elements found in a periodic table can bond with others. Thus, this property is typically used to determine the chemical properties of elements.
Oxygen has a total number of eight (8) electrons and as such the [tex] O^{2-}[/tex] is able to gain (receive) two (2) more electrons in order to have the same electron arrangements as the noble gas i.e an atom of neon that has a total number of ten (10) electrons.
Hence, [tex] O^{2-}[/tex] contains the same number of electrons as an atom of neon.
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Directions: count each side of the reaction then Circle yes or no if it follows the law of conservation of mass
Answer:
Explanation:
before the reaction you have K=2 and Cl=4
after the reaction K=2 and Cl=2 so it does not follow the law of conservation
Which of the following is the best hypothesis?
O A. Why does salt water boil at a higher temperature than
pure water?
O B. Americans use too much salt when they cook.
O C. If I add salt to water, it will cause the boiling point to increase.
D. It's better to cook pasta in salt water than in pure water.
explain how a motorcar engine produces nitrogen oxides
Answer: combustion causes a chemical reaction between nitrogen and oxygen in the engine.
Explanation:
Nitrogen oxides are produced in combustion processes, partly from nitrogen compounds in the fuel, but mostly by direct combination of atmospheric oxygen and nitrogen in flames. Nitrogen oxides are produced naturally by lightning, and also, to a small extent, by microbial processes in soils.
Answer:
when fuels are burned in vehicle engines high temperatures are reached. at these high temperature nitrogen and oxygen from the air combine to produce nitrogen
Which has kinetic energy?
Ob
a tank of gasoline
a moving car
a battery
Ос
Od
water in a reservoir
Answer:
a moving car
Explanation:
because The faster an object is moving, the more kinetic energy it has. Any object that is moving has kinetic energy – the moving object has energy because of its motion.
Which of the following is a difference between naming ionic and covalent compounds?
Group of answer choices
In ionic compounds the ending of the second element changes to -ide, but not in covalent compounds.
In covalent compounds, the prefix of the first element is always ignored but the prefix in the second element depends on the subscript of the element. In ionic compounds, the subscript on each element does not affect the name of the compound.
In covalent compounds the ending of the second element changes to -ide, but not in ionic compounds.
In covalent compounds, the prefix of the first element and second element depends on the subscript of each element. In ionic compounds, the subscript on each element does not affect the name of the compound.
The difference between naming ionic and covalent compounds is that, in ionic compounds the ending of the second element changes to -ide, but not in covalent compounds.
Ionic compounds are compounds that are formed by the by the transfer of electrons from a metal to a nonmetal. Covalent compounds are formed when electrons are shared between nonmetals.
For ionic compounds, the name of the second element(the nonmetal) often ends in -ide. For instance; sodium bromide, cesium oxide and potassium nitride. This does not apply when naming covalent compounds. The are named based on the subscripts of each element in the compound.
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How are the atomic number and the number of protons related to each other?
If an atom has a diameter of 395 pm,
what is its radius?
Answer:
197.5pm
Explanation:
Given parameters:
Diameter of the atom = 395pm
Unknown:
Radius of the atom =?
Solution:
Radius is the half of diameter;
Radius = [tex]\frac{diameter}{2}[/tex]
Radius = [tex]\frac{395}{2}[/tex] = 197.5pm
The mixture and elements of Coffee w Cream and Sugar
what are two ways in which you can increase the potential energy of a marble on ramp
Answer:
You can make the ramp really steep and hold the marble at the top of it
Explanation:
The statement of two ways in which increase the potential energy that is "potential energy is declining, while its kinetic energy is rising. Due to friction, potential energy is also transformed into heat."
What is potential energy?Potential energy is the energy stored in an object due to its location relative to some zero position, that objects can be compressed such as rubber bands, trampolines, and bungee cords are examples of potential energy.
A marble dropped at the top of the ramp seems to have more gravitational force than one discharged further down the ramp, and that potential energy is turned into kinetic energy when the marble is again dropped and begins to roll down the ramp.
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Which observation is the best indication that a chemical reaction has occurred?
A. Change in temperature
B. Presence of ashes
C. Change from liquid to gas
D. Absence of fizzing
Answer:
B: Presence of ashes
Explanation:
Burning molecules turns them into other molecules
Answer:B
Explanation:
How to do this question plz answer me
Answer:
dissolved
Explanation:
The figure shows sodium chloride is in solution. It gets that way by being dissolved.
What is the smallest unit of cellular organization?
Answer:
A cell
Explanation:
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Construct the chemical formulas for the ionic compounds.
Ionic compounds are formed from metal and non-metal elements
Further explanationThe chemical formula of compounds (especially ionic compounds) can be determined from the charge of each ion.
Determination of the ionic charge of the constituent elements of the compound can be seen from the electron configuration to achieve stability according to the octet rule
The charge of each ion will be crossed in the compound
Aluminum bromide
Al³⁺ + Br⁻ ⇒ AlBr₃
Magnesium bromide
Mg²⁺ + Br⁻ ⇒ MgBr₂
Sodium sulfide
Na⁺ + S²⁻ ⇒ Na₂S
Sodium nitride
Na⁺ + N³⁻ ⇒ Na₃N
When vinegar and baking soda react, the mixture becomes cold to the touch and a gas and a new liquid substance are formed. Which best describes what is occurring in the reaction? The reaction is chemical and endothermic. The reaction is chemical and exothermic. The reaction is non-chemical and endothermic. The reaction is non-chemical and exothermic.
Answer:
A
Explanation:
The mentioned reaction between vinegar and baking soda is a type of chemical reaction and endothermic reaction as the reaction proceeds with absorption of energy which turns the mixture cold.
What is endothermic reaction?An endothermic reaction is defined as a chemical reaction which is a thermodynamic process accompanied by an increase in enthalpy of the system.In this process, a system absorbs energy from the surroundings which is mainly thermal energy.
Thus an endothermic reaction leads to an increase in the temperature of the system with a decrease in the temperature of the surroundings.Endothermic reactions usually involve the formation of bonds which requires input of energy.In endothermic reactions, entropy of the surrounding decreases.
Many endothermic processes involve the physical changes rather the chemical changes.In an endothermic reaction ,the potential energy of products is greater than that of reactants.
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compare the size of F- and Na+ with atomic size of Neon?
Fluorine's atomic configuration is (2,7). As it's charge is -1, it will have 8 electrons in it's outermost shell thus filling its octate. similarly, Sodium loses one electron.
There you go :)
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[tex]\huge\boxed{Sublimation}[/tex]
_____________________________________Sublimation:Sublimation is a process in which the solid molecules gain energy from their surrounding and they now have enough energy to overcome the force of attraction with the neighboring molecules, thus they escape into the surrounding without going through the liquid phase, that means they directly jump to the vapor phase.
_____________________________________EndothermicThose process which absorb energy from their surrounding to form the product are called endothermic process. Since the SUBLIMATION requires additional energy, it is an endothermic change.
_____________________________________Best Regards,'Borz'Describe the chemical makeup of DNA. (site 1)
Answer:
DNA, or Deoxyribonucleic acid, has three types of chemical component: phosphates, a sugar known as deoxyribose, and four nitrogenous bases which are:
-adenine
-guanine
-cytosine
-thymine.
Two of the bases, adenine and guanine, have a double-ring structure characteristic of a type of chemical called a purine.
Hope this helped,
Philip
Brainliest always appreciated! <3
An example of a physical property of an element is the element's ability to what?
Explanation:
Appearance, melting point, density, solubility, polarity
Scientists believe that the earth's core is:
Design criteria are the desired features of a design. Identify at least two criteria for the design of the ammonia-making process. Explain why these criteria are important.
Answer:
The ammonia production design process has two design requirements;
Sustainable renewable energy production of hydrogen. Sustainable use of another thermal ammonia-water process to retrieve ammonia throughout the wastewater.Explanation:
In the following process, ammonia is provided by natural gas:
[tex]H_2 + RSH \to RH + H_2S\\\\H_2S + ZnO \to ZnS + H_2O \ \ (Waste \ water)\\\\CH_4 + H_2O \to CO + 3H_2\\\\CO + H_2O \to CO_2 + H_2\\\\[/tex]
Ammonia would then be generated in a process called also as Haber-Bosch process by responding to produced hydrogen to nitrogen throughout the presence of catalysts.
[tex]3H_2 + N_2 \to 2NH_3[/tex]
Answer:
Sustainable renewable energy production of hydrogen.
Sustainable use of another thermal ammonia-water process to retrieve ammonia throughout the wastewater.
Explanation:
will mark BRAINLIEST
Answer:
A and D
Explanation:
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Answer:
here's your answer...
Explanation:
Full moon, also hey lol.
have a germ-free day.
Eliza places an 18-gram piece of an unknown substance into a graduated cylinder that is filled with 5 mL of water, and the water rises from the 5 mL line to the 8 mL. What is the density of the unknown substance in g/mL?
Answer:
6g/mL
Explanation:
Given parameters;
Mass of the unknown substance = 18g
Volume of water before the mass is introduced = 5mL
Volume of water after the mass is introduced = 8mL
Unknown:
Density of the mass = ?
Solution:
Density is the mass per unit volume of a substance.
Density = [tex]\frac{mass}{volume}[/tex]
Mass is the amount of matter in a substance
Volume is the space occupied by a body
Volume of the body = 8mL - 5mL = 3mL
Insert the parameters and solve;
Density = [tex]\frac{18g}{3mL}[/tex] = 6g/mL
Answer:
I think its 6g or 16g but im pretty sure its 6g
Explanation:
If 9.6 X 1021 molecules of hydrogen are reacted with excess nitrogen, how many liters of ammonia can be produced at STP?
The volume of NH₃ produced at STP : 0.237 L
Further explanationReaction
N₂ + 3H₂ → 2NH₃
1 mol = 6.02 x 10²³ particles
9.6 X 10²¹ molecules of Hydrogen, mol :
[tex]\tt \dfrac{9.61\times 10^{21}}{6.02\times 10^{23}}=1.596\times 10^{-2}~moles[/tex]
mol H₂ : mol NH₃ = 3 : 2
mol NH₃ :
[tex]\tt \dfrac{2}{3}\times 1.596\times 10^{-2}=0.0106[/tex]
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.
The volume of NH₃ :
[tex]\tt 0.0106\times 22.4=0.237~L[/tex]
List and define the 3 parts of a chemical equation (R->P).
Answer:
R- reactants
arrow- yields
p- products
Explanation:
mass density and volume of molasses
Answer:
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Explanation:
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Potato strips placed in a container of concentrated salt water will ultimately __.