Answer:
96mg
Explanation:
Since the half-life of Palladium-100 is 4 days and the sample has been reduced after 16 days, that means the sample has undergone four half-lives. To find the intial mass, just work backwards:
6 x 2= 1212 x 2= 2424 x 2= 48 48 x 2= 96As you see, I've worked backwards from the four half-lives. So the initial mass after 16 days is 96 mg.
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1
a
C
Copper(II) nitrate decomposes on heating. The reaction is endothermic.
2Cu(NO),(s) → 2CuO(s) + 4NO2(g) + 0,(9)
Sketch a reaction pathway diagram for this reaction to include the
activation energy
[3]
b Draw an energy cycle to calculate the standard enthalpy change for
this reaction, using enthalpy changes of formation.
[3]
Calculate the enthalpy change for this reaction using the following
enthalpy changes of formation.
AH, [Cu(NO, ),(s)] = -302.9 kJ mol-'
AH, [CuO(s)] =-157.3 kJ mol-!
AH [NO,(g)] = +33.2 kJ mol-!
[3]
d Copper(II) sulfate is soluble in water. A student dissolved 25.0 g of
copper(II) sulfate in 100 cm of water in a polystyrene beaker stirring
all the time. The temperature of the water fell by 2.9 °C.
i Calculate the enthalpy change of solution of copper(II) sulfate.
(specific heat capacity of water = 4.18 Jg1 °C ; relative
molecular mass of copper(II) sulfate = 249.7 g mol-')
[3]
ii Suggest one source of error in this experiment and explain how
the error affects the results.
[2]
[Total: 14]
This problem provides information about the decomposition of copper(II) nitrate to copper(II) oxide and dinitrogen monoxide; for example, it is endothermic, the enthalpies of formation and the chemical reaction, as well as copper (II) sulfate which when dissolved in water, exhibits a temperature decrease:
[tex]2Cu(NO_3)_2(s) \rightarrow 2CuO(s) + 4NO_2(g) + O_2(g)[/tex]
First of all, we can draw the reaction pathway as shown on the attached figure, by taking into account the positive enthalpy change as it is endothermic, so that the products turn out with higher energy than the reactants, for it to be positive. In addition, keep in mind that top point is the activation energy the reaction needs to take place.
Next, we calculate the enthalpy change for this reaction by using the general formula which subtracts the enthalpy of formation of products and reactants with each species' correct stoichiometric coefficient:
[tex]\Delta H=2\Delta _fH_{CuO}+4\Delta _fH_{NO_2}+\Delta _fH_{O_2}-2\Delta _fH_{Cu(NO_3)_2}[/tex]
So we plug in the given enthalpies of formation:
[tex]\Delta H=2(-157.3)+4(33.2)+(0)-2(-302.9)=424.0 kJ/mol[/tex]
Finally, we go over the calorimetry experiment, whereby the total heat absorbed by the copper(II) sulfate is calculated via the general heat equation, which includes the heat loss from the solution of water and the salt:
[tex]Q_{rxn}=-mC_w\Delta T\\\\Q_{rxn}=-(100+25)g*4.18\frac{J}{g\°C}*-2.9\°C=1515.25J[/tex]
By dividing the previous answer by the moles of salt:
[tex]n=25.0g*\frac{1mol}{249.7g}=0.100mol[/tex]
We can obtain the enthalpy change of solution of the copper salt:
[tex]\Delta _{dissolution}H=\frac{1,515.25J}{0.100mol} \\\\\Delta _{dissolution}H=15,134J/mol=15.1kJ/mol[/tex]
To conclude, it is important to note that one possible source of error is we are assuming the solution has the same specific heat to that of water and that is not necessarily true. Also, we are neglecting any heat transfer to and from the surroundings despite the polystyrene beaker is considered a heat isolator, which means the results cannot necesarilly be accurate and the enthalpy change could have turned out higher or lower in a rigoruous experiment.
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https://brainly.com/question/15862043https://brainly.com/question/11667877Silver, 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
3 sentances
Heat can be lost from the body in the same way that heat is lost from Earth's surface. Based on what you know about heat transfer from Earth's surface to the atmosphere, describe how the body can lose heat in each of these ways (radiation, conduction, convection).
Answer:
the body can losse heat through Radiation,since Radiation does not involve the direct contact of two mediums
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Which group of nonmetals will react with alkaline earth metals to form a compound in a one-to-one ratio?
Question 3 options:
Group 15
Group 16
Group 17
Group 18
Answer:
Group 17
Explanation:
Group 16 of nonmetals will react with alkaline earth metals to form a compound in a 1 : 1 ratio. Therefore, option (b) is correct.
What is the alkaline earth metals?Alkaline earth metals or Group 2 includes six elements which are Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra).
This group contains smooth, silver metals with a less metallic character than group 1. All alkaline earth metals have two valence electrons, giving a valency of 2. These metals easily lose electrons to form compounds via ionic bonds and become more stable.
The valency of calcium is 2 and the valency of the elements of group 16 is also 2. Therefore they can combine 1 : 1 ratio to form a neutral compound.
Ca²⁺ + O²⁻ → CaO
Therefore, the nonmetals of group 16 will react with alkaline earth metal.
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Name the method that used to separate the components of petroleum oil.
Answer:
fractional distillation
Explanation:
how many atoms are in 2CL2
Answer:
Chlorine molecules are composed of two atoms (Cl2).
There are four atoms in two molecules of chlorine as each molecule of chlorine is made up of two atoms.
What is an atom?An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.
The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.
Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.
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Match the vocabulary word to its definition.
neutron
the central part of the atom containing
protons and neutrons
proton
a negatively charged particle that orbits
the nucleus of an atom
nucleus
a neutral particle located in the nucleus
of an atom
electron cloud
a positively charged particle located in
the nucleus of an atom
electron
the area of the atom surrounding the
nucleus where electrons can be found
Intro
Done
Answer:
neutron --> a neutral particle located in the nucleus of an atomproton --> a positively charged particle located in the nucleus of an atomnucleus --> the central part of the atom containing protons and neutronselectron cloud --> the area of the atom surrounding the nucleus where electrons can be foundelectron --> a negatively charged particle that orbits the nucleus of an atomThe electron configuration of na atom is 2,8,1. Give the electronic configuration of C D G H
Answer:
Explanation:
Record the letters in your triangle from left to right A MAGNESIUM CHLORATE B MAGNESIUM SULFATE C MAGNESIUM HYPOCHLORIDE D MAGANESE PERCHLORATE E MN C10 F MGMNO G MANGANESE CHLORIDE
Soil forms layers when mixed with water. sand is found above what ?
Answer:
Explanation:
Clay:)Fill in the [?]
1.7 km = [?]m
Give your answer in standard form.
Answer: 1.7 km = [1700]m
1.7 × 10^3
Explanation:
Answer:
1700 meters
Explanation: hope it helps.
Hurry Answer for a Brainlist
Answer:
The most accurate and percise player was Josh
What is the powerhouse of the cell?
Answer:
Mitochondria
Explanation:
Mitochondria is the powerhouse of the cell, convert sustenance into energy, fueling the cell's activities. In addition to power, mitochondria also produce reactive oxygen
How many moles of iron are in 50.0g of iron? How many iron atoms are in 50.0g of iron?
Answer:
50g iron comprises 5.376 × 1023 atoms.
Explanation:
Achemist is studying an unknown substance and could break the substance into its elemental components only by using
chemical means?
how many grams and moles of gold are present in 8.09 x 10^28 atoms of gold?
Answer:
Explanation:
how many grams and moles of gold are present in 8.09 x 10^28 atoms of gold?
there are 6.02 x 10^23 molecules or atoms in 1 mole
of a compound or element
8.09 x 10^28 /(6.02 x 10^23) = 1.34 x 10^5 moles of Au
1 mole of gold (see periodic table for #79) 197 g
so 1.34 x 10^5 moles of Au weigh
197 x 1.34 x 10^5 = 2.64 x 10^7 g
your little gold treasure is worth
Gold Price Per Gram $59.87 x 2.64 x 10^7=
$$$$ 1.58 x 10^9
=$ 1,580,000,000
How to find formula for ionic compounds.
Answer:
I am using an example for this in this table it works for any other compound as well.
Guys I need help please! Do not scam me ok? Thanks:). Please take a screenshot and send thanks.
Answer:
thx for the points
Explanation:
no need brainliest
Write the configuration for electron: 4, 2, -1, +12
Answer:
-1
Explanation:
electrons are negative
Why cathode rays have reducing effect
Answer:
Cathode rays consist mainly of electrons, they ionize substance, this leads to reduction. Any ions produced are collect by an ion trap in the tube therefore anything the beam of electrons hits is going to gain electrons.
what wouldn't be a redox reaction?
Answer:
Explanation:
Combination of oxidation and reduction reactions.
Where there is oxidation, there is reduction too.
Count the atoms in 717 grams of Nitrogen.
Answer:
3.08x10^25
Explanation:
Divide the mass in grams by the molar mass of nitrogen (14.0067), then multiply the result by Avogadro's number (6.022x10^23). Then round to the correct amount of significant figures.
What type of reaction is shown below? Check all that apply. 2Na Cl2 → 2NaCl synthesis decomposition combustion.
Answer:
Synthesis
Explanation:
Trust me on this :)
Draw the structure of the product that is formed when the compound shown below is treated with ch3co3h under aqueous acidic conditions.
The structure of the product that is formed is (2R,3S)-hexane-2,3-diol
The missing compound from the given question known as Hex-2-ene is shown with its stick formula in the reactant side of the image attached below.
Alkene reacts with a peracetic acid via the process of epoxidation of alkenes to produce an intermediate known as oxiranes. This intermediate is later being treated with aqueous acid to give a chemical compound with two hydroxyl substituents known as the glycol(diol) family.
Hex-2-ene reacts with peracetic acid CH₃CO₃H.
During the process of the reaction, an oxygen atom is moved from the peracetic acid to the C = C double bond, generating an oxirane ring.
Here;
Peracetic acid is considered to be an electrophilic oxidizing agent because the transferred oxygen atom has a positive charge.
The intermediate (oxirane) is further reacted with aqueous acid to produce an enantiomer of the diol family.
Learn more about the epoxidation of the alkene family.
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You have a sealed 2 liter flask that contains nothing but water and carbon dioxide. The flask is half-filled with liquid water, has a temperature of 25°c, and the overall pressure within the flask is 0. 1 atm. How many moles of co2 are in the flask? at this temperature, you may take the kh value for co2 as 0. 033 m / atm.
In this exercise we want to calculate the amount of moles, so this is going to be:
[tex](4.6)(10^{-3}) \ mols \ CO_2[/tex]
Knowing that Henry's law is given by:
[tex]C = KHP[/tex]
Where constants are given by:
C = Concentration KH = Henry's law constant = [tex]0.033 m/atm[/tex]P = partial pressure = [tex]0.07 atm[/tex]Before we can find the concentration of CO2 (and hence the moles of CO2), we first need to find its partial pressure. We look up the vapor pressure of water at 25º and find it to be 0.03 atm. Since the total pressure is equal to 0.1 atm, this mean the partial pressure of:
[tex]CO_2 = 0.1 \ atm - 0.03 \ atm = 0.07 \ atm[/tex]
Now using Henry's law, we find the concentration:
[tex]C = (0.033)*( 0.07) = (2.31)*(10^{-3})[/tex]
Converting to moles of CO2, we have:
[tex](2.31)*(10^{-3})*( 2) = (4.6)*(10^{-3})[/tex]
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Does the sound wave above experience a change in pitch or loudness? Why? (PLS HELP 60 ILL PNTS AND ILL GIVE BRAINIEST!!
Answer:
Explanation:
Amplitude, or the size of the wave height, affects the loudness. Larger the amplitude, the louder the volume. Period, or the time it takes for the wave to complete one round, determines the pitch. Shorter period (or higher frequency) means higher pitch.
How does a cation attract an anion?
An ionic bond is formed through the transfer of one or more valence electrons, typically from a metal to a non-metal, which produces a cation and an anion that are bound together by an attractive electrostatic force.
Elements with ________________ first ionization energies and ___________ electron affinities generally form cations.
Answer:
elements with low first ionization energies and positive or slightly negative electron affinities generally form cations.
hope it is helpful:)
How many grams of zinc chloride could be formed from the reaction of 3. 57g zinc with excess hcl?.
Which wave characteristic determines color?
A. The number of waves that pass per second
B. The lowest point on the wave
C. The highest point on the wave
D. The measurement from crest to crest
WILL GIVE BRAINLY :3✌️
Answer:
The color or hue of light depends on its wavelength, the distance between the peaks of its waves. The brightness of light is related to intensity or the amount of light an object emits or reflects. Brightness depends on light wave amplitude, the height of light waves.
Explanation:
Hope this helps.
aldosterone plays a primary role in adjustment of ____________ excretion.