Answer:
Prudent execution of experiments requires not only sound judgment and an accurate assessment of the risks involved in the laboratory, but also the selection of appropriate work practices to reduce risk and protect the health and safety of trained laboratory personnel as well as the public and the environment. Chapter 4 provides specific guidelines for evaluating the hazards and assessing the risks associated with laboratory chemicals, equipment, and operations. Chapter 5 demonstrates how to control those risks when managing the inventory of chemicals in the laboratory. The use of the protocols outlined in Chapter 4 in carefully planned experiments is the subject of this chapter.
Explanation:
A rock has been placed in water. The mass of the rock is 20g. What is the rocks density
Answer: 20g/(volume of water displaced)
Explanation: Density = Mass/Volume Once the volume of displaced water is known, divide the 20 grams by the volume.
What does the half-life of a radioactive substance indicate?
A. It indicates how dangerous the substance is to humans.
B. It indicates how much energy is released over time.
C. It indicates how long it takes for the material to decay.
D. It indicates how long it takes until all radioactivity is gone
Answer:
it indicates how long it takes for the material to decay
Explanation:
hope this helps!
The half-life of a radioactive substance indicates how long it takes for the material to decay.
What is half-life of a radioactive?A half life is the amount of time it takes for half of a radioactive substance to decay.
Radioactive isotopes are defined as the isotopes which undergo decay processes very easily. They have very short half life. They are usually the isotopes of heavier elements.
Half life is defined as the time taken for the unstable isotope to fall to half its original value.
Hence, option C is correct.
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What is the treatment and disposal of Mercury
Alpha particle radiation will most likely result when
electrons gain energy.
atoms become charged.
two atoms are near one another.
the nucleus becomes unstable.
Answer:
electrons gain energy
Explanation:
Which functional group does ethylamine contain? please help I need to finish this test ASAP
Answer:
its A -NH2 (vmxkgcjfxjfkhcfgk)
assuming that you attend school 180 days a year for 8 hours a day from first through 12th grade youd be in class for a total of 2160 school days how many total years would you have been in school by the time you graduate
Answer:
2160 days divided by 365 days which is a year is equal to about 5.9 years in school * sighhh*
5.91780821918
It is hypothesized that the water on Earth came from
Answer:
The new research suggests that Earth's water came from both rocky material, such as asteroids, and from the vast cloud of dust and gas remaining after the sun's formation, called the solar nebula.
Explanation:
name the types of polymerization and the differences
How many atoms? H_____, O_____, Fe_____ Total atoms? _____ 3Fe(oh)2
Answer:
H = 6
O = 6
Fe = 3
Total atoms = 15
Explanation:
3Fe (OH)2
Fe = 1×3
O= 2× 3 = 6
H= 2× 3 = 6
Total atoms = 6+6+3=15
I hope I helped you^_^
3.
Carlos is trying to figure out the best place to put his router in order to get the best
signal. Which is not an independent variable?
A. Distance from the router
B. Signal strength at the computer
OUTPU
C. The number of walls between the router and computer
STATIO
D. The number of devices on the router
Answer:
right answer is option no c
Please help me please find the answer
Answer:
look at the pic above
Explanation:
i hope u got it......
A 0.450 M solution of HCl is prepared by adding some 1.50 M HCl to a 500 mL volumetric flask and diluting to the mark with deionized water. What volume of 1.50 M HCl must be added
Answer:
150 mL of 1.50 M HCL
Explanation:
So the equation you need to solve this equation is:
M1*V1=M2*V2 --> M1= Molarity of the acid you are diluting V1= Volume of the solution you need to dilute. M2=The molarity of thee solution you have made. V2=Volume of the solution you have made
M1= 1.50 M HCL
V1= Unknown
M2=0.450 M HCL
V2= 500 mL
Simple algebra says that V1= (1.5*500)/.450 = 150 mL of 1.50 M HCL
This picture shows students working in a
chemistry laboratory. What could they do to make
their lab safer?
Label the test tubes and plastic cups.
Move the fire extinguisher closer to their
table.
Wear chemical protective gloves.
Reduce the clutter on the table.
Stand at the table instead of sitting. Tie long hair back.
DONE
Answer:
yes it is true they apply necessary safety measures
Answer: Label the test tubes, wear chemical protective gloves, tie long hair back
Explanation:
Just got it wrong
In a human nose, the total area of the region that detects our odors is about ¾ in^2. Compare that to the sensory organ of a hunting dog, whose nose has an active area of about 65 cm^2.
Let it be x
[tex]\\ \sf\longmapsto \dfrac{3}{4}x=65[/tex]
[tex]\\ \sf\longmapsto x=65\times \dfrac{4}{3}[/tex]
[tex]\\ \sf\longmapsto x=\dfrac{260}{3}[/tex]
[tex]\\ \sf\longmapsto x\approx82[/tex]
What is the Molality of a solution prepared by dissolving 84.7 g of KMnO4 (potassium permanganate, an oxidizing agent) in 165 g of water?
a) 0.513 m
b) 11.3 m
c) 0.308 m
d) 3.25 m
e) 0.958 m
how did your estimated poputation size
compare with the actual population size
Answer:
HE coracle—as I had ample reason to know before I was done with her—was a very safe boat for a person of my height and weight, both buoyant and clever in a seaway; but she was the most cross-grained, lop-sided craft to manage. Do as you pleased, she always made more leeway than anything else, and turning round and round was the manoeuvre she was best at. Even Ben Gunn himself has admitted that she was "queer to handle till you knew her way."
Explanation:
help i have no idea what i’m doing and i’m failing this class
Answer:
c
Explanation:
esuba is activation energy
Classify the following as Physical or Chemical changes. a) Water evaporating _________________ b) Sulfur dioxide reacts with water to make acid rain ___________________ c) Metal rusting ______________________ d) Dissolving sugar in a cup of coffee _____________________ e) Burning of gasoline ________________________
Answer:
A) Physical
B) Chemical
C) Chemical
D) Physical
E) Chemical
Explanation:
Physical changes are reversible while chemical changes are not.
hich formula can be used to calculate the molar mass of hydrogen peroxide (H2O2)? (5 points)
Select one:
a.molar mass of H + molar mass of O
b.2 x molar mass of H + molar mass of O
c.molar mass of H + 2 x molar mass of O Incorrect
d.2 x molar mass of H + 2 x molar mass of O
Which of the following statements best defines the actual yield of a reaction? (5 points)
Select one:
a.The amount of product measured after a reaction
b.The ratio of measured yield over theoretical yield
c.The maximum amount of product that can be obtained Incorrect
d.The ratio of measured yield over stoichiometric yield
Answer:
which formula can be used to calculate the molar mass of hydrogen peroxide (H2O2)?
» d.2 x molar mass of H + 2 x molar mass of O
Explanation:
Since we've two hydrogen atoms and two oxygen atoms, we multiply each mass by 2
[tex] = (2 \times hydrogen) + (2 \times oxygen) \\ = (2 \times 1) + (2 \times 16) \\ = 2 + 32 \\ = 34 \: g[/tex]
Which of the following statements best defines the actual yield of a reaction?
» d.The ratio of measured yield over stoichiometric yield
Please help me please
Answer:
Sugar solution seperation method is Distillation
iron power and sand separation method is Magnetic separation
petrol and diesel separation method is Fractional Distillation
camphor and galss powder seperation method is Sublimation
have a great day ❤️
The purpose of graphs, charts and tables is to?
The density of water at 40•c is 0.992g/mL. What is the volume of 3.09 g of water at this temperature
Answer: 3.1149193
Explanation:
To calculate for the volume of a substance, simply get the ratio of the mass and density. Which is volume = mass/density.
volume = 3.09/0.992 = 3.1149193
A sample of a substance who only oxidizable material is tin in the +2 state, is titrated with a dichromate solution that was prepared by dissolving 1.226g of K₂Cr₂O₇ in enough water to give a volume of 250.00cm³. A 0.0821g sample of the substance required a volume of 23.90cm³ of the titrant to reach the equivalence point . The product of the oxidation of the tin in the +2 state is to tin in the +4 state . The reduction product of the dichromate , is chromium in the +3 state. Calculate the % of tin in the substance . ( NB: Assume the reaction to take place in acidic )
Given that, the sample of a substance who only oxidizable material is tin in the +2 state and we are meant to the determine the percentage composition of tin in the substance;
Then, the percentage composition of the tin in the substance is calculated as 172.84%
From the given information:
The molecular weight is the addition of all the atomic masses of a compound.
The molecular weight of K₂Cr₂O₇ is calculated as follows:
= (2 × 39.1) + (2 × 52) + (7 × 16)
= 294.2
The molecular weight of Sn²⁺ = 118.7
The oxidation half-reaction for Tin(ii) ion is as follows:
[tex]\mathbf{Sn^{2+}\to Sn^{4+}+2e^{-}}[/tex]
From the above equation, Tin (ii) ion oxidizes to Tin (iV) ion
The reduction of K₂Cr₂O₇ In the acidic medium, reduce Cr₂ to Chromium Cr³⁺.
[tex]\mathbf{K_2 Cr_2O_7 + 14H^{+}+6e^- \to 2K^+ + 2r^{3+} + 7H_2O}[/tex]
To calculate the percentage % of Tin in the sample, we must first know the Equivalent weight of each substance.
Calculating the equivalent weight (Eq. weight) of each substance in the samples, we have the following:
For K₂Cr₂O₇:
[tex]\mathbf{Eq. weight = \dfrac{molecular \ weight }{numbers \ of \ electrons \ lost \ or \ gained }}[/tex]
[tex]\mathbf{Eq. weight \ of \ K_2Cr_2O_7 = \dfrac{294.2 }{6}}[/tex]
[tex]\mathbf{Eq. weight \ of \ K_2Cr_2O_7 = 49.03 \ g/eq}[/tex]
[tex]\mathbf{Eq. weight \ of \ Sn^{2+} = \dfrac{118.7 }{2}}[/tex]
[tex]\mathbf{Eq. weight \ of \ Sn^{2+} =59.35 g/eq}[/tex]
The next step is to determine the Normality of the Solution.
Normality refers to the mole number per liter of the solution
[tex]\mathbf{Normality \ of \ K_2Cr_2O_7 = \dfrac{1.226 \ g }{49.03}\times \dfrac{1000}{250}}[/tex]
[tex]\mathbf{= \dfrac{4.904}{49.03} N}[/tex]
So, 23.90 mL of [tex]\mathbf{ \dfrac{4.904}{49.03} N}[/tex] of K₂Cr₂O₇ is required to be present in the solution.
= [tex]\mathbf{=23.90 mL \times \dfrac{4.904}{49.03 } \ of \ Sn \ ion}[/tex]
Thus, the amount of Sn in the sample is calculated as:
[tex]= \mathbf{\dfrac{4.904}{49.03}\times \dfrac{59.35}{1000}\times 23.90 \ mL}[/tex]
= 0.1419 g
Finally, the percentage composition of tIn (Sn) in the sample is:
[tex]\mathbf{= \dfrac{0.1419}{0.0821}\times 100\%}[/tex]
= 172.84%
NOTE: A 0.0821g sample of the substance was given. Ideally, it should be 0.821g. But the calculation was based on the data given.
Therefore, from the above explanation, we can conclude that the percentage % of Sn in the sample is 172.84%
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8. Predict the missing products of the double replacement reaction: MgCl2 + Na2S—___+____
a. MgS + NaCl2
b. MgS + NaCl
c. MgNa + CIS
d. MgNa2 + Cl2S
Answer:
d.MgNa2+Cl2S
Explanation:
the reaction should balance on both sides
RUNNING OUT OF TIME! !!Please HELP!!
Which option describes the particles of water as liquid water actively boils to become steam?
A. The particles will gain kinetic energy and increase temperature during boiling.
B. The particles lose kinetic energy and decrease temperature during boiling.
C. The particles will have the same average kinetic energy and the same temperature during boiling.
D. The particles will have the same average kinetic energy and a decrease in temperature during boiling.
Answer:
correct answer is A
Explanation:
The option which describes the particles of water as liquid water actively boils to become steam is: A. The particles will gain kinetic energy and increase temperature during boiling.
Water refers to a liquid molecule that is typically made up of two (2) main chemical elements; hydrogen and oxygen in the ratio of two (2) to one (1) [2:1].
Generally, the boiling point of water is approximately at one hundred (100) degrees Celsius and at this temperature, water is typically converted into steam. This is usually as a result of the fact that, the particles of water gains more kinetic energy and an increase in temperature as it boils to become steam.
In conclusion, heating water causes its temperature to increase and the water molecules would gain kinetic energy as it actively boils to become steam.
Read more: https://brainly.com/question/19695951
Please check if that’s right
Answer:
Explanation:
yes
When is the chemical equilibrium in a chemical equation observed
Answer:
When the concentration of reactants is equal to the concentration of the products. [ when reaction rate is zero ]
Explanation:
This is only observed in a reversible reaction
[tex].[/tex]
What do you know about the corpuscular nature of matter?
Answer:
It is a simple and clear account of the development of the codpuscular or, as sortie prefer to call it, the electronic, theory, of matter to explain the passage of electricity through metals and gases.
Explanation:
THE present volume is an expansion of six lectures delivered by; Prof. J. J. Thomson in his capacity of professor at: the Royal Institution. It is a simple and clear account of the development of the corpuscular, or, as sortie prefer to call it, the electronic, theory, of matter to explain the passage of electricity through metals and gases. The last two chapters are devoted to consideration of the properties of model atoms built up of corpuscles, and the evidence in favour of the view that the number of the corpuscles in an atom is about the same as its atomic weight in terms of hydrogen.
Who first proposed the idea of the atom
hi, there!
The ancient atomic theory was proposed in the 5th century bc by the Greek philosophers Leucippus and Democritus
Solid calcium oxide and gaseous water are produced by the decomposition of solid calcium oxide hydroxide. Write a balanced chemical equation for this reaction.
[tex]\boxed{\sf {Ca(OH)_2(s)\atop Calcium\:Hydroxide}\longrightarrow {CaO(s)\atop Calcium\;oxide}+{H_2O(g)\atop water}}[/tex]
On reactant side
Hydrogen= 2atomsOxygen=2atomsCalcium=1atomOn product side
Hydrogen=Oxygen=2atomsCalcium=1atom.hence balanced.
