Answer:
A. It is possible not all of the water was evaporated from the sand, causing the recovered mass to be higher
D. While drying the NaCl, the liquid boiled and some splattered out of the evaporating dish, causing the recovered mass to be higher.
Explanation:
Sand absorbs water and stores it. The sunlight causes the water to evaporate but sand can hold some of the water inside it. This results in increase in mass of the sand. The mass of sand before and after the water evaporation can be different.
Indicate which of these statements about catalysts are true. 1) In an equilibrium process, a catalyst increases the rate of the forward reaction, but leaves the rate of the reverse reaction unchanged. 2) A catalyst is not consumed in the course of a reaction. 3) A catalyst must be carefully chosen to shift the equilibrium toward products.
Answer:
2) A catalyst is not consumed in the course of a reaction.
Explanation:
A catalyst is a substance which increases the rate of chemical reaction and remains chemically unchanged at the end of the reaction. The addition of a catalyst increases the rate of both reversible and irreversible reactions. including reversible reactions involving a final equilibrium state. In reversible reactions, catalysts speed up the time for equilibrium to be attained.
Considering the given statements about catalysts:
1) In an equilibrium process, a catalyst increases the rate of the forward reaction, but leaves the rate of the reverse reaction unchanged.
False: A catalyst increases both the forward and reverse reaction rates equally, thereby allowing the system to reach equilibrium faster.
2) A catalyst is not consumed in the course of a reaction.
True: Catalysts are substances that increase reaction rates without being consumed in the reaction.
3) A catalyst must be carefully chosen to shift the equilibrium toward products.
False: A catalyst does not affect the extent or position equilibrium of a reaction since a catalyst speeds up both the forward and back reactions by equal amounts , rather it helps a reaction achieve equilibrium faster.
We obviously cannot wait for million years to determine the half-life of technetium, or even years to determine the half-life of plutonium. The half-life of a substance is determined using a Geiger counter, which is essentially a tube filled with an inert gas. When a particle decays and produces radiation, it briefly ionizes the gas and produces a detectable electric pulse, which is amplified and counted by a detector (before digital displays were available, you would hear clicks and see a needle register on a dial). Determine the formula for the half-life of a substance with an initial count of pulses and a count of pulses minutes later.
The question is incomplete, the complete question is;
We obviously cannot wait for 4 million years to determine the half-life of technetium, or even 87.7 years to determine the half-life of plutonium. The half-life of a substance is determined using a Geiger counter, which is essentially a tube filled with an inert gas. When a particle decays and produces radiation, it briefly ionizes the gas and produces a detectable electric pulse, which is amplified and counted by a detector (before digital displays were available, you would hear clicks and see a needle register on a dial). Determine the formula for the half-life of a substance with an initial count of No pulses and a count of N1 pulses M minutes later.
Answer:
M1/2 = 0.693/k
Explanation:
Given that the initial count rate is No pulses
The count rate after M minutes is N1
Then from;
A = Aoe^-kt
A= N1
Ao=No
I can now write;
N1 = Noe^-kM
The half life is the time taken for the activity of the radioactive nuclide to reach half its initial value. Hence;
N1/No =e^-kM = 1/2
Taking natural logarithm of both sides as shown below;
-kM1/2 = ln(1/2)
M1/2 = - (ln(1/2)/k)
M1/2 = 0.693/k
Definition: This is a net gain or loss of electrons.
Example: Your hair gains one when you pull a wool sweater over your head.
res)
Term:
Answer:
Elecric charge/ Electricity
Explanation:
Electric charge is the net gain or loss of electrons
I hope im right!!
Where are new volcanoes in the Hawaiian island chain forming
Answer:
The Hawaiian Islands are a very small section of a huge chain of volcanic islands that crosses the northern half of the Pacific Ocean, called the Hawaiian-Emperor Volcanic Island Chain, which is over 6,000 kilometres long. The chain is linear, with a large bend in the middle: the southern half is called the Hawaiian Ridge and the northern half is called the Imperial Seamount.
Explanation:
Which best describes the process that occurs when liquid water becomes
ice?
Answer:
Freezing
Explanation:
When a liquid goes to a solid, this process is called freezing.
Answer:
The water molecules get condensed and form a solid matter called ice. This process is called Condensation.
what does the word interact
Lift
Fly
Discuss
Work with
Answer:
The answer would be work with.
Explanation:
Because, if we know what the word interact means then we can look for a word similar to interact. hope this makes sense <3.
Explain how you would separate a mixture of soil. pebbles, and iron filings.
Explanation:
if they aren't in a solvent, then you magnetize first, to remove the iron fillings, secondly, you can sieve to separate the sand and pebbles
Separate the pebbles by either straining them out or pulling each one out separately with tweezers or your fingertips.
What is separation?To separate their soil mixes using the tools you have supplied, ask the groups to develop a plan. They might consider using forceps to separate the soil, shaking it between two tumblers, placing it in a water-filled tumbler, or pouring it through air. Invite student groups to present their ideas.
Pbbles - Separate the pebbles by either straining them out or pulling each one out separately with tweezers or your fingertips. As a strainer, a colander or a section of window screen works well. Iron fillings Using a magnet, it is simple to remove the tiny iron filings from the mixture.
Therefore, separate the pebbles by either straining them out or pulling each one out separately with tweezers or your fingertips.
To know more about separartion here:
https://brainly.com/question/16774902
#SPJ2
If I have 2.500 grams of magnesium how many moles of magnesium do I have?
Answer:
0.1029(rounded to sig figs)
Explanation:
convert from grams to moles
Amount in grams/molar mass of substance
Molar mass of Mg=24.305
So, 2.500/24.305=0.1028594939
Rounded to 0.1029
What % of original U238 remains after three half lives?
1-50
2-25
3-12.5
4-6.25
Answer:
12.5
Explanation:
After three half-lives, one eighth (1/2 x 1/2 x 1/2) of the uranium-238 will remain. One-eighth equals 12.5%
An aqueous solution contains
32.7% KCI (weight weight %)
How many grams of KCl are
contained in 100 g of this solution
Molar Mass
KCE: 74.55 g/mol
H20 18.016 g/mol
Answer:
32.7
Explanation:
I just did it and got it right
Hydrogen has an oxidation number of +1 in all compounds excepts when it binds with metals and has an oxidation state of -1.
Answer:
See explanation
Explanation:
In the periodic table, hydrogen is placed in group 1 for convenience. Hydrogen is not a metal, however, its common oxidation state is +1. It easily forms a univalent positive ion just like group 1 elements.
So, when hydrogen is combined with strongly electropositive metals such as sodium, lithium, etc, hydrogen accepts one electron and exhibits an oxidation state of -1 in those compounds.
Such compounds in which hydrogen is combined with strongly electropositive metals to give a binary compound is called a hydride.
what is the percentage composition of carbon and hydrogen in ethane(c2h6,molecular mass 30.0)
Answer
% of C in C2H6= (2×12)/30×100=80%
% of H in C2H6= (3×2)/30×100=20%
Explanation:
2C+3H2-C2H6
nC=12, nH=1, nC2H6=30
2moles of C-1mole of C2H6
3moles of H-1 mole of C2H6
% of C in C2H6= (2×12)/30×100=80%
% of H in C2H6= (3×2)/30×100=20%
What is the product of the equation shown?
2 Na + S203
A. Na S203
B. NaS40
C. Na2S205
D. Na2S2O3
Answer:
D
Explanation:
balancing of chemical equations
help please i need this
HELPPP HURRY FIRST GET BRAINLEST The rusting of steel wool occurs when the iron in the steel wool combines with what substance?
carbon dioxide
hydrogen
nitrogen
oxygen
Answer:
iron oxide. aka. oxygen
Explanation:
Rust is the result of a chemical reaction between iron and oxygen, otherwise known as iron oxide. Since steel wool -- and steel in general -- is largely made of iron, steel wool is prone to rust if it doesn't have a rustproof coating on it. The actual reaction that creates rust happens when two iron atoms mix with three oxygen atoms in water; the oxygen bonds to the metal, and a new compound is formed.
How many molecules are in 13.2 L F2
Answer:
3.55 x 10^23 molecules F2
Explanation:
molecules = moles x avogadro number
1 mole of gas occupies 22.4 L
moles of F2 = 13.2/22.4= 0.589 moles
moles F2 = 0.589 x 6.022 x 10^23 = 3.55 x 10^23 molecules F2
What type of reaction is displayed below?
HCI + NAOH → NaCl + H20
Answer:
neutralization reaction
Explanation:
This reaction involve an acid (HCl) reacting with a base (NaOH), producing a salt (NaCl) and water. Therefore it's a neutralization reaction
Which one of the following represents an acceptable set of quantum numbers for an electron in an atom? (arranged as n, l, ml, and ms)
2, 2, -1, -1/2
3, 3, 3, 1/2
3, 3, 3, -1/2
5, 4,- 5, 1/2
2, 1, 0, 1/2
NEEED HELP NOW
A new drug has been released to the public and is popular among
consumers. It is effective in relieving high blood pressure. However, it has
altered some patients' personalities. Which stage of the engineering process
may address this negative side effect?
A. Evaluating test results
B. Looking for improvements
C. Screening
D. Testing
Answer: looking for improvements
Explanation:
Answer:
B. Looking for improvements
Explanation:
took the quiz and got in right on a pex
A chemist needs to know the mass of a sample of to significant digits. He puts the sample on a digital scale. This is what the scale shows:
0
0
0
7
6
.
3
g
If this measurement is precise enough for the chemist, round it to significant digits.
Otherwise, press the "No solution" button.
Whoever gets it right gets brainliest!!
When different atoms join together, they are called a compound. Compounds are made of molecules (so molecules could be an alternate answer, but not all molecules are compounds)
Answer:
it is compound
Explanation:
Two or more elements combined into one substance through a chemical reaction, such as water, form a chemical compound. All compounds are substances, but not all substances are compounds.
help someone i need this
HELP I WILL GIVE YOU BRAINLIST!!!
Pick one substance (ex: water and table salt) and compare two of the atoms connected to each other (ex: H and O, Na and Cl) and answer the following questions for each pair:
1)Are they close or far away from each other on the periodic table?
Do they have similar atomic radii?
2)Do they have a large or small difference in ionization energy? What about for electron affinity?
15POINTS I NEED HELP WITH THIS QUESTION PLEASE!
Answer:
12.76 g
Explanation:
Step 1: Write the balanced equation
4 Fes + 7 O₂ ⇒ 2 Fe₂O₃ + 4 SO₂
Step 2: Calculate the moles corresponding to 11.15 g of O₂
The molar mass of O₂ is 32.00 g/mol.
11.15 g × 1 mol/32.00 g = 0.3484 mol
Step 3: Calculate the moles of SO₂ produced from 0.3484 moles of O₂
The molar ratio of O₂ to SO₂ is 7:4.
0.3484 mol O₂ × 4 mol SO₂/7 mol O₂ = 0.1991 mol SO₂
Step 4: Calculate the mass corresponding to 0.1991 moles of SO₂
The molar mass of SO₂ is 64.07 g/mol.
0.1991 mol × 64.07 g/mol = 12.76 g
The concentration of a benzene solution prepared by mixing 12.0 g
C6H6 with 38.0 g CCl4 is __________ molal
Answer: The concentration of a benzene solution is 4.05 molal
Explanation:
Molality of a solution is defined as the number of moles of solute dissolved per kg of the solvent.
[tex]Molality=\frac{n\times 1000}{W_s}[/tex]
where,
n = moles of solute
[tex]W_s[/tex] = weight of solvent in g
moles of [tex]C_6H_6[/tex] = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{12.0g}{78g/mol}=0.154mol[/tex]
Now put all the given values in the formula of molality, we get
[tex]molality=\frac{0.154\times 1000}{38.0g}=4.05[/tex]
Therefore, the concentration of a benzene solution is 4.05 molal
If 4 moles of sulfur reacts with 9.5 moles of oxygen, how many moles of oxygen would remain after the reaction ?
help please will give brainly if right
Answer:
B and D
Explanation:
Because its adaptions they need to survive in the cold.
A cook prepares a solution for boiling by adding 12.5 g of NaCl to a pot holding 0.750 L of water. At what temperature should the solution in the pot boil? {Normal boiling point is 100oC and Kb = 0.512 oC kg/mol and density of water is 1 kg/L}
Thanks!!
Answer:A cook prepare a solution for boiling by adding 12.5g of NaCl to a pot holding 0.750L of water. ... 12.5g of NaCl to a pot holding 0.750L of water. At what temperature should the solution in the not boil? *. 1 ... Which of the following is best suited to be counted by moles a. roses in a store b. books in a library c.
Explanation:
3 Zn + 2 MnF3 ---------> 2 Mn + 3 ZnF2
Using the reaction above, calculate how many grams of manganese (Mn) are produced in this reaction when 8.5 moles of Zinc (Zn) are used as a reactant?
Answer:I’ll ask my teacher
Explanation:
A group of students is setting up a test to see whether earthworms, like those shown in the photo, prefer rough or smooth surfaces
Answer:
they like smooth
Explanation: