When Katarina finds a stain at a crime scene the first thing she should do is to scrape the substance into a plastic bag. That is option B.
Who is a forensic scientist?A forensic scientist is a professionally trained individual that applies their knowledge in the field of criminology by using evidence found on the crime scene to narrow down a suspect.
When a stain is being noticed by the forensic scientist, the first step should be to secure the stain for further investigation.
To secure the stain, the scientist should scrap the stain into a plastic bag and this should be taken to the laboratory for further evaluation and investigation.
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Complete the balanced dissociation equation for the compound below. If
the compound does not dissociate, write NR after the reaction arrow.
LiOH(s) →
LiOH ⇌ Li + + OH - NR
When there are too many OH ions, water dissociates fully to the left, possibly leaving only Li + and OH ions and H 2 O molecules.
IN CHEMISTRY, WHAT IS AN ION?An atom or collection of atoms that is classified as an ion as a different number of electrons than proton atoms. The particle is a positive ion, also known as a cation, if the number of electrons is smaller than the number of protons.
How do ions form?Ions are created when there are more protons in an atom than electrons, which is the case in all atoms. An atom that has gained or lost one or more electrons, and as a result has a negative or positive charge, is what is referred to as an ion. Exchanging electrons between atoms or molecules is the process of ionization.
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How many milliliters of 0.100M NaOH are required to neutralize the following solution 5.00mL of.0500M HCI
1) Set the chemical equation
[tex]\text{NaOH + HCl = NaCl + H}_2O[/tex]2) Find out how many moles of HCl react in the solution.
[tex]\text{moles of HCl = }\frac{0.0500\text{ M}}{\square}\cdot\frac{5.00\text{ mL}}{\square}\cdot\frac{1\text{ L}}{1000\text{ mL}}=\text{ 0.00025 moles of HCl}[/tex]3) Find out how many moles of NaOH reacted with HCl
[tex]\text{moles of NaOH = }\frac{0.00025\text{ moles of HCl}}{\square}\cdot\frac{1\text{ mole of NaOH}}{1\text{ mole of HCl}}=\text{ 0.00025 moles of NaOH}[/tex]4) Find out the milliliters of NaOH
[tex]mL\text{ of NaOH = }\frac{0.00025\text{ moles of NaOH}}{0.100\text{ M}}\cdot\frac{1000\text{ mL}}{1\text{ L}}\text{= 2.50 mL}[/tex]Which is the least electronegative element?Group of answer choicescarbonnitrogenoxygenaluminum
In order to solve this question, we can use the electronegativity table (or also just a regular periodic table), which will give us the values of electronegativity for each element.
As we can see in this table, the least electronegative element will be Al, with only 1.61 of value. If you were with a regular periodic table, you could find this answer by thinking about the periodic table trend, or we can also call it a rule, that in most elements the electronegativity will grow in value from left to right and from the bottom to the top, then you would also get Al as your answer
Answer = Al, letter D
If 3.8 moles of P4 are used, how many moles of O2 are needed?
1) Write the chemical equation.
[tex]P_4+O_2\rightarrow P_4O_{10}[/tex]2) List the elements in the reactants and in the products.
Reactants.
P: 4
O: 2
Products
P: 4
O: 10
Balance O.
[tex]P_4+5O_2\rightarrow P_4O_{10}[/tex]3) Moles of O2 needed.
The molar ratio between P4 and O2 is 1 mol P4: 5 mol O2.
[tex]mol\text{ }O_2=3.8\text{ }mol\text{ }P4*\frac{5\text{ }mol\text{ }O_2}{1\text{ }mol\text{ }P_4}=19\text{ }mol\text{ }O_2[/tex]If 3.8 mol P4 are used, 19 mol O2 are needed.
.
A patient receives 100 mL of 25% (m/v) mannitol solution every hour.How many grams of mannitol are given in 1 hour?Express your answer using two significant figures.
Explanation:
A patient receives 100 mL of a 25 % m/v mannitol solution every hour. We have to find the mass in grams of mannitol that the pacient is receiving in 1 hour. We can use the formula of the mass/volume percent to find the answer to our problem.
% m/v = mass of solute in g/(volume of solution in mL) * 100 %
We know the concentration of the solution and we have the volume of solution in mL, so we can solve the formula for the mass of solute and get the answer to the problem.
25 % m/v = mass of solute in g/100 mL * 100 %
mass of solute in g = 25 * 100/100 g
mass of solute in g = 25 g
Answer: In 1 hour the patient receives 25 g of mannitol.
10) Identify the substance as an acid or a base and put an "X" in the box.
l
Identify the substance as an acid or a base and put an "X" in the box lemon juice is the acid sodium hydroxide is the base and ammonia is the weak base and HCl is the strong acid
An acid is the any hydrogen containing substances that is capable of donating a proton to another substances and base is the molecule or ion able to accept a hydrogen ion from acid and acidic substances are usually identified by their sour taste and here given example are lemon juice acidic because they contain high amount of citric acid and sodium hydroxide is the base because they dissociate completely into the solution to form hydroxide ion and ammonia is the weak base because nitrogen atom has electron pair that easily accept a proton and HCl is the strong acid because it dissociate almost completely
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Ozone molecules in the upper atmosphere absorb radiation. If the radiation has a wavelength between 240 nm and 310 nm, the ozone molecules will decompose into oxygen molecules and oxygen atoms. The oxygen atoms then recombine with the oxygen molecules to make more ozone, releasing heat. This converts light energy into heat energy and insulates the Earth. ***** O3(g) → O2(g) + O(g) -> light energy absorbed heat energy released O2(g) + O(g) 03(g) a) What kind of electromagnetic radiation has a wavelength between 240 and 310 nm? b) Which wavelength represents the minimum amount of energy required for this reaction to proceed: 240 nm or 310 nm? c) Calculate the minimum amount of light energy that must be absorbed to convert 1 mole of ozone into oxygen molecules and atoms. Report your answer in kJ/mol. [4 Marks]
a)ultraviolet rays
Explanation:
ultraviolet rays are electromagnetic waves that are found in the range of 240 and 310 somewhere in between the electromagnetic spectrum
b)310nm causes minimum energy because the ultraviolet rays have reacted with oxygen to produce zone
c) 310nm to
=3.1×10^-7m once converted find the frequency using the converted wavelength as your wavelength AND once that has been done find your
E=hv=6.626×10^-34×9.68×10^14=6.414×10^-10J convert J to KJ/MOL will be 386.3KJ/MOL.
A popular car has an engine that is reported to have a volume of 5840 . What is the size in cubic inches?
By using an appropriate conversion factor, the size of this popular car's engine is equal to 356.78 cubic inches.
What is a conversion factor?A conversion factor simply refers to a number that is typically used to convert a number in one (1) set of units to another, either by dividing or multiplying.
Generally speaking, an appropriate conversion factor to an equal value must be used when it is necessary to perform any mathematical conversion.
Conversion:
1 cubic centimeter = 0.061023744094732 cubic inches.
5,840 cubic centimeter = X cubic inches.
Cross-multiplying, we have:
X = 0.061023744094732 × 5,840
X = 356.78 cubic inches.
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Complete Question:
A popular car has an engine that is reported to have a volume of 5840 cm³. What is the size in cubic inches?
Initially a sample of nitrogen gas is found in a pressure of 4.62 atm under the temperature of 27.0°C
The change in the temperature of the gas, given that the volume is held constant is 63 °C
How to determine the change in temperatureLet's begin by obtaining the new temperature of the gas. This can be obtained as follow:
Initial pressure (P₁) = 4.62 atm Initial temperature (T₁) = 27 °C = 27 + 273 = 300 KNew pressure (P₂) = 5.59 atm New temperature (T₂) =?P₁ / T₁ = P₂ / T₂
4.62 / 300 = 5.59 / T₂
Cross multiply
4.62 × T₂ = 300 × 5.59
Divide both side by 4.62
T₂ = (300 × 5.59) / 4.62
T₂ = 363 K
Subtract 273 to obtain answer in °C
T₂ = 363 – 273 K
T₂ = 90 °C
Finally, we shall determine the change in the temperature. This is illustrated below:
Initial temperature (T₁) = 27 °CNewl temperature (T₂) = 90 °CChange in temperature (ΔT) =?ΔT = T₂ – T₁
ΔT = 90 – 27
ΔT = 63 °C
The, the change in the temperature is 63 °C
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Complete question:
See attactched photo
Calculate the frequency of light that has a wavelength of 16.23 * 10^-9 m.
The frequency of the light that has a wavelength of 16.23 × 10⁻⁹ meter would be 1.84 × 10¹⁶ Hz , as the frequency and the wavelength are inversely proportional to each other.
What is Wavelength?It can be understood in terms of the distance between any two similar successive points across any wave for example wavelength can be calculated by measuring the distance between any two successive crests.
C = λν
As given in the problem we have to calculate the frequency of the light if the wavelength of light is 16.23 × 10⁻⁹ meter.
The frequency of the light = 3 × 10⁸ / 16.23 × 10⁻⁹
= 1.84 × 10¹⁶ Hz
Thus, the frequency of the light would be 1.84 × 10¹⁶ Hz.
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Recall the postulates of kinetic-molecular theory. Read the list and check all the statements that apply to the behavior of an ideal gas:1. gas particles behave like hard spheres2. gas particles travel randomly3. gas particles are attracted to each other4. energy is lost when gas particles collide 5. average kinetic energy of a collection of gas particles depends on the temperature6. gas particles occupy most of the space within a container7. gas particles have mass and volume
Answer:
Chemistry - States of matter - Kinetic Molecular Theory
This is the theory that explains the states of the matter and is based on the idea that matter is composed of tiny particles that are always on motion.
Part 1: Check all the statements that apply to the behavior of an ideal gas
The behaviors that apply are:
1.Gas paarticles behave like hard sphares.
2.Gas particles travel randomly.
5. Average kinetic energy of a collection of gas particles depends on the temperature.
Part 2: According to kinetic-molecular theory the one that would not be considered an ideal gas is:
A gas with highly polar molecules that have very strong intermolecular forces.
This is because the theory consideres thhat there are no forces of attraction of repultion between gas particles.
A scientist uses a graduated cylinder to measure 100.0 mL of gasoline for an experiment. The density of gasoline is 0.774 g/mL. What is the mass of this gasoline sample?
Answer:
100ml x 0.774
divide by 4
x by 8
What is the limiting reactant if 43.4 g of NH3 react with 30 g of NO? The balanced equation is 4NH3 + 6NO --> 5N2 + 6H2O
Answer
NO is the limiting reactant
Explanation
Given that:
The mass of NH3 that reacted = 43.4 g
The mass of NO that reacted = 30 g
The equation for the reaction is: 4NH3 + 6NO --> 5N2 + 6H2O
What to find:
The limiting reactant.
Step-by-step solution:
The first step is to convert the given mass of the reactants to moles.
Using the mole formula and the molar masses of (NH3 = 17.0 g/mol and NO = 30.0 g/mol)
[tex]\begin{gathered} Moles=\frac{Mass}{Molar\text{ }mass} \\ \\ Moles\text{ }of\text{ }NH_3=\frac{43.4g}{17.031g\text{/}mol}=2.55\text{ }mol \\ \\ Moles\text{ }of\text{ }NO=\frac{30g}{30.0g\text{/}mol}=1.0\text{ }mol \end{gathered}[/tex]The final step is to determine the limiting reactant by comparing the mole ratio from the given equation with the mole ratio in the step above.
From the equation, 4 moles of NH3 reacted with 6 moles of NO
So 2.55 moles of NH3 is expected to react with (2.55 x 6)/4 = 3.825 moles of NO
1.0 mol NO is less than 3.825 mol NO, hence, NO is the limiting reactant because it will be the reactant to be completely used up first.
A sample of nitrogen gas, occupies 50.0 mL at 27 °C and 500. torr. What pressure will it have if cooled to –73 °C while the volume remains constant?
Answer:
333.33 torr
Explanation:
Initial Pressure = 500 torr
Let Final Pressure be 'P'
Initial Temperature = 27 °C = 300 K
Final Temperature = -73 °C = 200 K
Initial Volume = Final Volume
From Combined Gas Law,
(Initial Pressure × Initial Volume) / Initial Temperature = (Final Pressure × Final Volume) / Final Temperature
So, P = (500 torr × 200 K) / 300 K = 333.33 torr
Determine whether each combination will produce aprecipitate. If a precipitate forms, enter its chemicalormula. If no precipitate forms, enter NONEHg2(NO3)2(aq) + BaCl₂(aq)H₂SO4(aq) + NaOH(aq)AgCH3CO₂(aq) + Cs₂SO4(aq)NH4Br(aq) + K3PO4(aq)
First, we have to complete the reactions with the respective products:
[tex][/tex]Draw the Lewis structure for chloroform, CHCl3
Answer:
Explanation:
To write the Lewis structure, it is important to look for the electrons of each atom in the Periodic Table of Elements.
C has 4 valence atoms, H has 1 valence atom and Cl has 7 valence atoms.
We write the C atom in the center. Then we have to complete the Octet in each atom, except in Hydrogen, because it can only has 2 electrons bonded.
When copper is heated with an excess of sulfur, copper(I) sulfide is formed.
In a given experiment, 1.53 g of copper was heated with excess sulfur to yield 1.76 g of copper(I) sulfide.
What is the percent yield?
If 1.53 g of copper is heated with excess sulfur to yield 1.76 g of copper (I) sulfide, the percent yield would be 75.43%.
Percent yieldThe percent yield of a reaction is the actual yield relative to the theoretical yield of the same reaction.
The percent yield of a reaction is mathematically expressed as:
Percent yield = actual yield/theoretical yield x 100%.
Let us now consider the reaction in question. The equation of the reaction is given as:
[tex]Cu + S --- > CuS[/tex]
The mole ratio of the copper that reacts to the copper sulfide that is formed is 1:1.
Recall that: mole = mass/molar mass
The molar weight of copper is 63.55 g/mol
Mole of 1.53 g copper = 1.53/63.55
= 0.024 moles
The equivalent mole of copper sulfide produced will also be 0.024 moles.
The molar mass of CuS is 95.61 g/mol
Mass of 0.024 moles CuS = 0.024 x 96.61
= 2.32 g
2.32 g is the theoretical yield of the reaction. But 1.76 g of copper sulfide is the actual yield.
Percent yield = 1.75/2.32 x 100%
= 75.43%
Thus, the percent yield of the reaction, if 1.53 g of copper is heated with excess sulfur to produce 1.76 g of copper (I) sulfide, is 75.43%.
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I need your help with this question
No need explaining just say the answer thanks
Answer: CHOCH
The third one
Explanation:
The designations for the first four electron energy sublevels with the maximum number of electrons that can be accommodated in each sublevel ares:2, p:6, d:10, and f:14s:2, p:8, d:10, and f:14s:1, p:2, d:3, and f:4s:2, p:8, d:18, and f:32
So,
The s sublevel has just one orbital, so can contain 2 electrons max. The p sublevel has 3 orbitals, so can contain 6 electrons max. The d sublevel has 5 orbitals, so can contain 10 electrons max. And the 4 sublevel has 7 orbitals, so can contain 14 electrons max.
Therefore, the correct answer is:
s:2, p:6, d:10, and f:14
If the volume is 10 and the mass of water is 9.99 what is the density
Answer:
0.999
Explanation: divide by 10
Consider this reaction:3Ca(s)+2H3PO4(aq)=Ca3(PO4)2(s)+3H2(g)How many grams of calcium are required to produce 50.500 g of calcium phosphate (MW = 310.19g/mol) assuming an excess of Phosphoric acid?
Answer
19.6 grams
Explanation
Given:
Mass of calcium phosphate produced = 50.500 g
Equation: 3Ca(s) + 2H3PO4(aq) ---> Ca3(PO4)2(s) + 3H2(g)
What to find:
The grams of calcium required to produce 50.500 g of calcium phosphate.
Step-by-step solution:
From the equation, 3 mol Ca produce 1 mol Ca3(PO4)2
1 mole Ca3(PO4)2 = 310.19 grams
1 mole Ca = 40.078 grams
This means, (3 x 40.078 g) = 120.234 g Ca produce 310.19 g Ca3(PO4)2
So x grams Ca will be required to produce 50.500 grams Ca3(PO4)2
x grams Ca will be equal
[tex]\frac{50.500\text{ }g}{310.19\text{ }g}\times120.234g\text{ }Ca=19.6\text{ }grams\text{ }Ca[/tex]The grams of calcium required to produce 50.500 g of calcium phosphate = 19.6 grams
A mixture of nitrogen and hydrogen gas is compressed from a volume of 90.0L to a volume of 89.0L, while the pressure is held constant at 44.0atm. Calculate the work done on the gas mixture. Round your answer to 2 significant digits, and be sure it has the correct sign (positive or negative).
The PV work formula is:
w = -Pexternal * ΔV
w = -44.0 atm * (89.0 - 90.0)
w = -44.0 atm * -1 L
w = 44.0 L atm
For each L atm, we will have 101.325 Joules, therefore
44.0 L atm * 101.325 J
w = 4458.3 J or 4.4 kJ
a gas has a volume of 103.4 L at 27.5 atm. what will it’s volume be if the pressure is changed to 69.3 atm
In this question, we have a gas presenting volume and pressure, and the gas law that we can use to calculate it is Boyle's gas Law, which perfectly correlates both pressure and volume, the formula is:
P1V1 = P2V2
We have:
P1 = 27.5 atm
V1 = 103.4 L
P2 = 69.3 atm
V2 = ?
Now we add these values into the formula:
27.5 * 103.4 = 69.3 * V2
V2 = 41.0 L
The 946 mL of Gatorade bottle contains FD&C Blue I at concentration of 0.100mg/L. Molar mass of Blue I is 792.84 g/mol.
a) Calculate the molarity of Blue I in Gatorade.
b) How many molecules of Blue I would you consume by drinking the entire bottle of Gatorade.
The molarity of Blue I in Gatorade is 0.00010 mol L⁻ molecules of Blue I would you consume by drinking the entire bottle of Gatorade is 4.77 mol
Molarity is the amount of substance in certain volume of solution and also moles of solute per liter of solution
Here given data is
Volume = 946 mL
Molar mass = 792.84 g/mol
Concentration = 0.100mg/L
We have to find molarity and molecules of Blue I would you consume by drinking the entire bottle of Gatorade = ?
Molarity = number of moles of solute/volume of solution
Molarity = 0.100mg/L/946 mL
Molarity =0.00010 mol L⁻
Now we have to find molecules of Blue I = ?
Molecules of Blue I = 792.84 g/mol × avagadro number
Avagadro number = 6.022×10²³
Molecules of Blue I = 792.84 g/mol×6.022×10²³
Molecules of Blue I = 4.77 mol
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How many moles are there in 2.50 grams of ethanol, C2H6O ?
In a 250 mL sealed container at 150℃, 0.50 mol of both iodine gas I2(g) and bromine gas, Br2(g) are mixed and allowed to react until they form an equilibrium with iodine monobromide gas IBr(g). The equilibrium constant for this reaction is 1.2 x 102. What are the equilibrium concentrations for iodine gas and bromine gas? I2(g) + Br2(g) ↔ 2IBr(g)
answer and explanation
now that we have the x value we can find the equilbrium concentratoins of tehegases
for Iodine
x =0.456
= 0.5-x
= 0.5-0.456
= 0.035mols
concentration = 0.035mols/ 0.250L
= 0.14M
for Bromine
x =0.456
= 0.5-x
= 0.5-0.456
= 0.035mols
concentration = 0.035mols/ 0.250L
= 0.14M
the concentration of the two gases is 0.14M
Answer the following questions assuming you have a 1.3M (molarity) solution ofHNO3 (5 points each, 15 points total)A. How many moles of HNO3 would you have in 0.6 liters of the above solution?B. How many grams of HNO3 would be present in 0.6 liters of the above solution?C. If you began with 0.6 liters of solution, and diluted the solution to a concentration of 0.45M, whatwould the final volume of the solution be?
A) 0.78 moles
B) 49.15grams
C) 1.73L
Explanations:The formula for calculating the molarity of a solution is expressed as;
[tex]\begin{gathered} molarity=\frac{moles}{volume} \\ moles=molarity\times volume \end{gathered}[/tex]Given the following parameters
molarity of HNO3 = 1.3M
volume of HNO3 = 0.6L
A) moles of HNO3 = 1.3 * 0.6
moles of HNO3 = 0.78moles
B) Mass of HNO3 = moles * molar mass
Mass of HNO3 = 0.78 * 63.01
Mass of HNO3 = 49.15grams
There are 49.15grams of HNO3 present in 0.6L of the solution
C) According to dilution formula
[tex]\begin{gathered} C_1V_1=C_2V_2 \\ V_2=\frac{C_1V_1}{C_2} \\ V_2=\frac{1.3\times0.6}{0.45} \\ V_2=\frac{0.78}{0.45} \\ V_2=1.73L \end{gathered}[/tex]Therefore the final volume of the solution will be 1.73L
calculate the number of litres of each gas givin the following number of moles at STPhow many litres of gas is in 0.001 mol H2S
STP stands for Standard Temperature and Pressure. Nowadays the STP is temperature of 0°C (273.15K) and pressure of 1 bar.
Assuming the gas behaves as an ideal gas, in these conditions the volume of each mol of gas is approximately 22.7 L.
Using rule of three, we can calculate the volume of 0.001 mol of H₂S:
Volume --- Number of moles
x --- 0.001 mol
22.7L --- 1 mol
[tex]\begin{gathered} \frac{x}{22.7L}=\frac{0.001}{1} \\ x=22.7\cdot0.001L \\ x=0.0227L \end{gathered}[/tex]So, the volume is approximately 0.0227 L.
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Electron capture occurs when one of the electrons in the atom is captured by the atom's nucleus. The captured electron combines with one proton to form a neutron.
We have to find the nuclide that is produced when the aluminum-28 undergoes an electron capture.
If we look for the atomic number of Al in the periodic table we will see that it is 13. That means that it has 13 protons. Then we are given the atomic mass of aluminum, it is 28. That means that if we add the number of protons and the number of neutrons we get 28.
atomic mass = n° of protons + n° of neutrons = 13 + 15 = 28
atomic number = n° of protons = 13
The nucleus of the aluminum atom will capture one electron that will combine with a proton of the nucleus to form a neutron. So the atomic number will change because it will have 1 proton less. But the atomic mass won't change because we are losing one proton but winning a neutron, so it remains the same. After the electron capture, the new nuclide will have:
atomic mass nuclide = n° of protons + n° of neutrons = 12 + 16 = 28
atomic number nuclide = n° of protons = 12
If we look for the element that has an atomic number of 12 in the periodic table we will see that it is magnesium.
Finally we can express this like a reaction:
28 0 28
Al + e --------> Mg
13 -1 12
Answer:
28
Mg
12
asap
compare and contrast chemical and physical equilibrium
Answer:
The difference between chemical and physical equilibrium. Physical is a reversible change of state. Chemical is a reversible chemical reaction that can go in the direction to create products or to create reactants.
A physical equilibrium is an equilibrium state in which the physical state of the system does not change. Chemical equilibrium is the equilibrium state in which the concentrations of reactants and products is not changed with time.
Hope this helps!