Answer:
b) warming up a) wavelength a) blank c) sample
Explanation:
To run a spectrophotometry experiment, begin by warming up the spectrophotometer and preparing the samples. It is important that the equipment is warmed up for at least 30 minutes before starting the measurements.
Be sure to select the correct wavelength, then run a measurement on the blank solution. The selected wavelength depends on the analyte of interest. The black solution contains the same matrix but it doesn´t contain the analyte.
Follow up by running measurements on sample solutions. Once data is collected, turn off the instrument, clean the area, and discard the samples. The samples are those of unknown concentration that we want to determine.
To run a spectrophotometry experiment, begin by cleaning the spectrophotometer and preparing the samples. Be sure to select the correct wavelength, then run a measurement on the sample solution. Follow up by running measurements on aqueous solutions. Once data is collected, turn off the instrument, clean the area, and discard the samples.
Spectrophotometry is a technique used to measure the interaction of light with matter, specifically the absorption, transmission, or reflection of light by a sample. It involves the use of a spectrophotometer, an instrument that measures the intensity of light as a function of its wavelength or frequency.
In spectrophotometry, a sample is exposed to light of a specific wavelength or a range of wavelengths. The sample may absorb certain wavelengths of light, which can be detected and measured by the spectrophotometer. The amount of light absorbed is related to the concentration of the analyte in the sample, allowing for quantitative analysis.
Learn more about Spectrophotometry, here:
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Give the following for SO2 and BrF5:
(a) Number of domains on central atom (b) Domain geometry (c) Molecular geometry (d) Hybridization of central atom
Answer:
The given molecules are SO2 and BrF5.
Explanation:
Consider the molecule SO2:
The central atom is S.
The number of domains on S in this molecule is three.
Domain geometry is trigonal planar.
But there is a lone pair on the central atom.
So, according to VSEPR theory,
the molecular geometry becomes bent or V-shape.
Hybridization on the central atom is
[tex]sp^{2}[/tex].
Consider the molecule BrF5:
The central atom is Br.
The number of domains on the central atom is six.
Domain geometry is octahedral.
But the central atom has a lone pair of electrons.
So, the molecular geometry becomes square pyramidal.
The hybridization of the central atom is [tex]sp^{3} d^{2}[/tex].
The shapes of SO2 and BrF5 are shown below:
Calculate the density of CO2 at a pressure of 685.0 torr and 41.0°C .
R=0.0821 (L*atm)/(mol *K)
T=41+273=314 k
M=(12)+(16×2)=44g/mol
d=PM/RT
d=685×44/0.0821×314
d=1169.15 g/L
Which metal does not form cations of differing charges?
Transition metals
Most transition metals differ from the metals of Groups 1, 2, and 13 in that they are capable of forming more than one cation with different ionic charges. As an example, iron commonly forms two different ions
Based on your knowledge of factors affecting the rate of reaction, why is there a danger of explosions in places such as flour mills and coal mines where there are large quantities of powdered, combustible materials? 
How does the Big Bang theory explain why there is a lot of hydrogen and helium in the universe?
Answer:
when the explosion happened the matter fussed into elements as the electrons portions Nd notrons were compresed into the elements beacuase hydrogen has 1 nutron proton and electron surronding its core
Lemon juice has a pH of 2. What is the hydrogen ion concentration of lemon juice?
A mixture of gases at 2.99 atm can You have two gases, and , at the same temperature. Determine the ratio of effusion rates of and .ists of 13.2 moles of hydrogen gas and 19.1 moles of helium gas. Determine the partial pressure of the helium gas.
Answer:
Given total pressure of the gas mixture(hydrogen and helium) is 2.99 atm
Number of moles of hydrogen is ---- 13.2 mol
Number of moles of helium is ---- 19.1 mol
Determine the partial pressure of the helium gas.
Ratio of effusion rates of the two gases.
Explanation:
According to Dalton's law of partial pressures,
partial pressure of a component gas in a mixture is:
partial pressure of a gas = total pressure x mole fraction
mole fraction of helium gas is:
[tex]mole fraction of helium gas = \frac{number of moles of helium gas}{total number of mioles} \\=>mole fraction of He= \frac{19.1mol}{(19.1+13.2)mol} \\=>mole fraction of He = 0.591\\[/tex]
Partial pressure of He gas is:
[tex]Partial pressure of He =mole fraction of He * total pressure\\ =0.591 x 2.99atm\\ =1.77atm[/tex]
Effusion rate of a gas is inversely proportional to its square root of its molecular mass.
[tex]\frac{rate of effusion of H2 gas}{rate of effusion of He gas} =\sqrt{\frac{molar mass of He gas}{molar mass of H2 gas} } \\=> \frac{rate of effusion of H2 gas}{rate of effusion of He gas}=\sqrt{\frac{4g.}{2g} } \\=>\frac{rate of effusion of H2 gas}{rate of effusion of He gas}=1.414:1[/tex]
Hence, rates of effusion of H2:He is 1.414:1.
a polluted lake is 0.300 μg (micrograms) per liter of water, what is the total mass of mercury in the lake, in kilograms, if the lake has a surface area of 15.0 square miles and an average depth of 27.0 feet?
Answer:
95.9 kg
Explanation:
First we convert 15.0 mi² to m²:
15.0 mi² * ([tex]\frac{1609.34 m}{1mi}[/tex])² = 3.88x10⁷ m²Then we convert 27.0 ft to m:
27.0 ft * [tex]\frac{0.3048m}{1ft}[/tex] = 8.23 mNow we calculate the total volume of the lake:
3.88x10⁷ m² * 8.23 m = 3.20x10⁸ m³Converting 3.20x10⁸ m³ to L:
3.20x10⁸ m³ * [tex]\frac{1000L}{1m^3}[/tex] = 3.20x10¹¹ LNow we calculate the total mass of mercury in the lake, using the given concentration:
0.300 μg / L * 3.20x10¹¹ L = 9.59x10¹⁰ μgFinally we convert μg to kg:
9.59x10¹⁰ μg * [tex]\frac{1kg}{1x10^9ug}[/tex] = 95.9 kgwhy Hydroxide ion is less strong base than hydride ion
Answer:
The hydride ion,H−is a stronger base, so it will abstract a proton from the water. As the water will give protons, so water will work as an acid and an acid-base reaction will take place. Hydride ions get protons from water and form hydrogen gas and hydroxide ions.
Sodium hydride is the chemical compound with the empirical formula NaH. This alkali metal hydride is primarily used as a strong yet combustible base in organic synthesis. NaH is a saline (salt-like) hydride, composed of Na+ and H− ions, in contrast to molecular hydrides such as borane, methane, ammonia, and water.
only some particles split up into smaller particles
Answer:
Everything around you can be broken down into smaller particles called atoms. The particles of one substance are all the same and different substances are made up of different particles.
Explanation:
Determine the Concentration of the Unknown Strong Acid
In this activity you will use the virtual lab to determine the concentration of a strong monoprotic acid. To do this, you can perform
a titration using NaOH and phenolphthalein found in the virtual lab. (Note: The concentration of the acid is between 0.025M and
2.5M so you will need to dilute the NaOH solution so that the volume to reach the endpoint is between 10 and 50 mL).
Once you have determined the concentration of the acid, please enter your answer into a form at the bottom of this page.
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Unknown Acid Problem
Stockroom
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2. Which of the following best represents the nucleus in a model of an atom?
a positively charged nucleus consisting of protons and neutrons
O a positively charged nucleus consisting of electrons and neutrons
a neutral nucleus consisting of protons and neutrons
a neutral nucleus consisting of electrons and neutrons
Answer:
A positively charged nucleus consisting of protons and neutrons
Explanation:
The atomic nucleus is a positively charged region located at the core of an atom that consists of positively charged protons and neutral neutrons while the negatively charged electrons make up the outer cloud (electrons are therefore not contained in the nucleus).
HELP PLS THIS IS SO HARD AHHHHHHH
what are the most common measurements used to describe gases in chemistry
Four quantities must be known for a complete physical description of a sample of a gas: temperature, volume, amount, and pressure. ... The height of the mercury column is proportional to barometric pressure, which is often reported in units of millimeters of mercury (mmHg), also called torr.
iodide (KI). Identify the correct products of this
reaction. (Note that NO3? is the nitrate ion, a
polyatomic ion.)
AgNO3 + KI – ?
AgK + INO3
✓
Agl + KNO3
Ag + K + I + NO3
COMPLETE
What type of reaction is this?
Answer:
AgNO3 + KI → Agl + KNO3. Double-replacement reaction
Explanation:
Based on solubility rules, Silver, Ag produce an insoluble salt in presence of halides (Fluorides F-, Chlorides Cl-, Iodides, I-, and bromides Br-). That means the mixture of AgNO3 (Ag⁺ ions) with KI (I- ions) produce AgI as insoluble salt.
The reaction is:
AgNO3 + KI → Agl + KNO3And this is a double-replacement reaction where the cations exchange of anion to produce 2 new compounds.
Answer:
AgI + KNO3
Explanation:
double replacement
Gamma rays have the highest frequency among all common electromagnetic radiations. It means the gamma rays have the highest energy and the longest wavelength
Answer:
yes
Explanation:
cos of high electron transfer
The pH for several solutions is given below. After filling in each blank with the correct number, arrange the substances mentioned at the beginning of each sentence in order from most acidic to most alkaline.
a. Black coffee has a pH of 5, therefore its H+ concentration is __________times greater than a solution with a pH of 10
b. Urine has a pH of 6, therefore its H+ concentration is ________times greater than a solution with a pH of 9.
c. Household ammonia has a pH of 11, therefore its H+ concentration is__________ times less than a solution with a pH of 7 .
d.Grapefruit juice has a pH of 3, therefore its H+ concentration is_______ times greater than a solution with a pH of 5 .
2
100
1000000
4
100000
10
3
100,000
1000
5
how
the
Way
of
it's
the Base
Consider the dehydration of 2-propanol in sulfuric acid: There is a scheme of a reaction where CH3 CH CH3 with an OH group attached to the second carbon atom dehydrated in the presence of H2SO4. Draw the structure for the product of the dehydration of 2-propanol.
Answer:
CH2=CH-CH3
Explanation:
One of the ways of preparing alkenes is by dehydration of alcohols using sulphuric acid. The sulphuric acid merely acts as a catalyst in the process.
It begins with the protonation of the -OH group. This is followed by loss of water molecule since water is a good leaving group.
Loss of a proton now completes the mechanism and regenerates the acid catalyst.
The mechanism of dehydration of 2-propanol as well as the product formed in the process is shown in the image attached to this answer.
Learning Task 1. Read each item carefully. Choose the letter of your answer.
1. Which type of soil is characterized as having the finest particles holding greater amount of water?
A. Loam
B. Clay
C. Sand
2. Which type of soil is best for planting?
A. Loam
B. Clay
C. Sand
3. How does each soil types differ?
A. Texture
B. Color
C. Both A & B
4. Which type of soil do you usually expect if the community is along the seashore?
A. Loam
B. Clay
C. Sand
5. Why is soil important to living things?
A. Forms part of the earth where animals live
B. Provides the necessary nutrients needed by plants
C. Serves as a place where people live
D. All of the above
Answer:
1. B
2. A
3. C
4. C
5. D
Explanation:
Soil is regarded as the solid unconsolidated material of the earth crust. Soil is of three different types namely: Sandy soil, clay soil and loamy soil. These three different soil types possess different properties that distinguish them. Some of them are:
- CLAY soil is characterized as having the finest particles and can hold greater amount of water i.e. have a high water holding capacity.
- LOAMY SOIL is the best soil type for planting agricultural crops because it has the highest concentration of nutrients that suited for plant growth.
- loamy, Sandy and clay differ in how we feel when touched i.e. texture, and colour.
- SANDY soils are the kind of soils that are found in Sea shores and beaches.
- Soil is important to living things as it forms part of the earth where animals live, provides the necessary nutrients needed by plants, serves as a place where people live.
aluminum chloride and bubbles of hydrogen gas are produced when metallic aluminum is placed in hydrochloride acid. what is a balanced equation for this reaction?
Answer:
AlCl3 + HCl ===> AlCl4 +H-
Balance the equation by ion electron method
Answer:i believe you are to decompose the formula (i think)
The sloth is able to camouflage by moving really slowly and
A. changing colors
B. hanging upside down
D. having fur that is a similar color to tree barks with algae growing on it
Answer:
D. having fur that is a similar color to tree barks with algae growing on it
Explanation:
Choice A doesnt make sense because sloths do not change colors, and hanging upside down would not protect you from prey or blend in. D matches the description of a sloth.
Answer:
Having fur that is a similar color to tree barks with algae growing on it.
Explanation:
what is the enthalpy of the overall chemical reaction
Answer:
For a chemical reaction, the enthalpy of reaction (ΔHrxn) is the difference in enthalpy between products and reactants; the units of ΔHrxn are kilojoules per mole
What is the concentration of a solution that is made by diluting 50.0 mL of a 0.40 M NaCl solution to a final volume of 1000.0 mL?
Answer:
The correct answer is 0.020 M.
Explanation:
To solve this problem, we can use the equation M1V1 = M2V2, where M represents the molarity of the solution and V represents the volume of solution. Since we are given that the original solution is 50 mL and 0.40 M, these values are V1 and M1, respectively. The solution after dilution has a volume of 1000 mL, so this value is V2. We are solving for the molarity after dilution, which represents M2.
If we plug in the values specified above, we get the following:
M1V1 = M2V2
(0.40 M)(50.0 mL) = (M2)(1000.0 mL)
Solving for M2, we get:
M2 = 0.020 M
Notice that our answer has 2 significant figures because 0.40 has 2 significant figures, the least of any values given in the problem.
Therefore, the answer is 0.020 M.
Hope this helps!
How much energy is produced when 13.1 g of tin reacts with 2.715 g of N2 ?
I.
3 Sn + 2 N2-----------Sn3N4 + 632 KJ
Hint change grams to moles first.
1 mole Sn= 119g
1 mole N2= 28 g
Answer:
23.2 kJ of energy are released by the reaction.
Explanation:
Hello there!
In this case, according to the given information, it turns out firstly necessary for us to calculate the moles of both tin and nitrogen and the produced moles of Sn3N4 product by each reactant as shown below:
[tex]13.1gSn*\frac{1molSn}{119gSn} *\frac{1molSn_3N_4}{3molSn} =0.0367molSn_3N_4\\\\2.715gN_2*\frac{1molN_2}{28gN_2} *\frac{1molSn_3N_4}{2molN_2} =0.0485molSn_3N_4[/tex]
Thus, since 13.1 grams of tin produce the fewest moles of Sn3N4 product, we infer tin is the limiting reactant, and the correct produced energy, due to this reaction is:
[tex]E=632\frac{kJ}{mol\ rxn}*\frac{1mol\ rxn}{1molSn_3N_4}*0.0367mol Sn_3N_4\\\\E=23.2kJ[/tex]
Regards!
Guys i need a long inforation about....
"Formation of colloids"
Please and thank you
Answer:
Colloids
There are two basic methods of forming a colloid: reduction of larger particles to colloidal size, and condensation of smaller particles (e.g., molecules) into colloidal particles. Some substances (e.g., gelatin or glue) are easily dispersed (in the proper solvent) to form a colloid; this spontaneous dispersion is called peptization. A metal can be dispersed by evaporating it in an electric arc; if the electrodes are immersed in water, colloidal particles of the metal form as the metal vapor cools. A solid (e.g., paint pigment) can be reduced to colloidal particles in a colloid mill, a mechanical device that uses a shearing force to break apart the larger particles. An emulsion is often prepared by homogenization, usually with the addition of an emulsifying agent. The above methods involve breaking down a larger substance into colloidal particles. Condensation of smaller particles to form a colloid usually involves chemical reactions—typically displacement, hydrolysis, or oxidation and reduction.
molar mass of Beryllium
Answer:
The molar mass of Beryllium is 9.012182 u
Calculate the amount of heat required to completely sublime 55.0 g of solid dry ice CO2 at its sublimation temperature. The heat of sublimation for carbon dioxide is 32.3 kj mol
Answer:
40.4 kJ
Explanation:
Step 1: Given data
Mass of CO₂ (m): 55.0 gHeat of sublimation of CO₂ (ΔH°sub): 32.3 kJ/molStep 2: Calculate the moles corresponding to 55.0 g of CO₂
The molar mass of CO₂ is 44.01 g/mol.
n = 55.0 g × 1 mol/44.01 g = 1.25 mol
Step 3: Calculate the heat (Q) required to sublimate 1.25 moles of CO₂
We will use the following expression.
Q = n × ΔH°sub
Q = 1.25 mol × 32.3 kJ/mol = 40.4 kJ
Which is most likely the reason the U.S government made such an investment
Answer:
The U.S government made such an investment because they're most likely to reduce harmful emissions.
Look at the equation CO2 + H2 = CO + H20.
CO is a ________
reactant and a product
reactant
product
Answer:
CO is considered as a product.
Explanation:
A general chemical equation for a combination reaction follows:
To write a chemical equation, we must follow some of the rules:
The reactants must be written on the left side of the direction arrow.
A '+' sign is written between the reactants, when more than one reactants are present.
An arrow is added after all the reactants are written in the direction where reaction is taking place. Here, the reaction is taking place in forward direction.
The products must be written on the right side of the direction arrow.
A '+' sign is written between the products, when more than one products are present.
For the given chemical equation:
are the reactants in the reaction and are the products in the reaction.
Hence, CO is considered as a product.