Isotopes are atoms that have the same mass number, but different numbers.
atomic. True or false
Answer: Im not sure but I think it is false.
Explanation:
PLS GUYS ITS FOR 10TH GRADE CHEM
Answer:
1. 2.63x10^6
2. 39.2
Both answers have been rounded
One the first chemistry test. 12 students got As, 18 students got Bs, and 20 students got Cs.
a. What is the percentage of students received Bs.
b. What is the percentage of students who received Cs?
Express your answer to the ones place.
Answer:
A. 36 percent recieved Bs
B. 40 percent of students received Cs
Explanation:
Amount of students: 12+18+20=50
Students with Bs: (18÷50) x 100 = 36%
Students with C's: (20÷50) x100 = 40%
On the first chemistry test 12 students got A, 18 students got B, and 20 student got C. Thus the percentage of students received B is 0.36 and percentage of students received c is 0.40
What is the percentage of students received B and C?In mathematics, a number or ratio expressed as a fraction of 100. It is often denoted using the percent sign %. A percentage is a dimension less unit and it has no unit.
In above question 12 student got A, 18 student got B, and 20 student got C.
So total number of student = 12 + 18 + 20 = 50.
Then the percentage of students received B is as follows:-
Percentage of students who got B = (student who got B/Total number of student) X 100.
=(18/50) X 100
= 36%
Now percentage of students who got C = (No of students who got C/Total students)X100
=(20/50) X 100
=40%.
Therefore,On the first chemistry test 12 students got A, 18 students got B, and 20 student got C. Thus the percentage of students received B is 0.36 and percentage of students received c is 0.40 percentage of students who got B is 36% and percentage of students who got C is 40%
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from the equation 2PbO + C = 2Pb + CO2, detemine which one is reactant is oxidised and which is reduced.
Answer:
Explanation:
C is oxidised because C up to C+4
PbO is reduced because PbO from Pb2+ down to Pb0
Answer:
lead (Pb) is reduced carbon is oxidized
what's the atomic weight of salt ?
Answer:
58.44 g/mol
Explanation:
58.44 g/mol
If the magnet loses its superconducting properties, all of the liquid helium could suddenly turn to a gas. If an MRI machine contains 1950 L liquid He with a density of 0.125g/mL, how many liters of He gas would be formed at 25°C and 1 atm? Use the ideal gas law. Round your final answer to two significant figures. Show your work. (4 points)
Answer:
Determine the volume of helium gas
Answer:
About 1,495 Liters of Helium.
Explanation:
To calculate the volume of helium gas formed when the magnet loses its superconducting properties, we can use the ideal gas law:
PV = nRT
Where:
P = Pressure (in atm)
V = Volume (in liters)
n = Number of moles of helium gas
R = Ideal gas constant (0.0821 L.atm/(mol.K))
T = Temperature (in Kelvin)
First, we need to find the number of moles of helium gas:
Given volume of liquid helium (V_liquid) = 1950 L
Density of liquid helium (ρ) = 0.125 g/mL = 0.125 g/cm³
To convert density from g/cm³ to g/L, we multiply by 1000:
Density of liquid helium (ρ) = 0.125 g/cm³ * 1000 cm³/L = 125 g/L
Mass of liquid helium (m) = Volume * Density = 1950 L * 125 g/L = 243,750 g
Next, we need to convert the mass of liquid helium to moles using the molar mass of helium:
Molar mass of helium (M) = 4.0026 g/mol
Number of moles (n) = Mass / Molar mass = 243,750 g / 4.0026 g/mol ≈ 60,907 mol
Now, we have the number of moles of helium gas (n), and we can calculate the volume of helium gas (V_gas) at 25°C (298.15 K) and 1 atm:
P = 1 atm
T = 25°C = 298.15 K
V_gas = nRT / P
V_gas = (60,907 mol) * (0.0821 L.atm/(mol.K)) * (298.15 K) / (1 atm)
V_gas ≈ 1,495 L
Therefore, approximately 1,495 liters of helium gas would be formed at 25°C and 1 atm when the magnet loses its superconducting properties.
What is the aim of cleaning of the iron nails before doing the experiment?
Assertion (A): An orbital cannot have more than two electrons, moreover, if an orbital has two electrons they must have opposite spins.
Reason (R): No two electrons in an atom can have the same set of all the four quantum
numbers.
a) Both A and R are true and R is the correct explanation of A.
b) Both A and R are true but R is not the correct explanation of A.
c) A is true but R is false.
d) Both A and R are false.
pls answer
Answer:
the correct answer is option ( A )
Both A and R are true and R is the correct explanation of A.
Explanation:
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Which state of matter has particles that vibrate and can change place but remain touching in a random arrangement.
A. Liquid
B. None of these
C. Plasma
D. Gas
The particles in the solid are touching with very little space between them. The particles in a liquid usually are still touching but there are some spaces between them. The gas particles have big distances between them.
...
Liquids Solids and Gases:
NON OF THESE
If you started with 2 moles of Nitrogen and 3 moles of Hydrogen, then you
would not have any leftover reactants. Explain which material would be
limiting since no hydrogen or nitrogen were left over?
N2 + 3H2 -> 2NH3
Answer: 0.3 moles NH3
Explanation:
what is mean by vector
Answer:
A quantity having direction as well as magnitude is called vector.
The compound KOH is ________. insoluble, because all compounds containing K are insoluble insoluble, because all compounds containing OH- are in soluble soluble, because all compounds containing K are soluble soluble, because all compounds containing OH- are soluble insoluble, because KOH is insoluble
Answer:
soluble because all compounds containing K are soluble
Explanation:
Most metal hydroxides are insoluble. However, alkali metal hydroxides (such as KOH and NaOH) are very soluble.
In the case of KOH, the K cation is attracted to the electronegative oxygen on water. The OH anion is capable of hydrogen bonding to the water. (Notice how OH⁻ is simply the deprotonated form of water.)
The compound KOH is soluble insoluble, because all compounds containing K are insoluble insoluble, because all compounds containing OH- are in soluble soluble, because all compounds containing K are soluble soluble, because all compounds containing OH- are soluble insoluble, because KOH is insoluble
What are alkalis?Alkalis are bases which are soluble in water. The basic alkalis are as follows:
KOHNaOHCa(OH)2Mg(OH)2 is insoluble in water.
In conclusion, KOH is a soluble base
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How does the chemistry of the ocean change in response to high levels of CO2 in the atmosphere?
WHICH STATEMENT BEST REPRESENTS A HYPOTHESIS
Answer:
D
Explanation:
Hypotheses are educated guesses, and the best answer is the one with an if, as it indicates that it's a guess.
Answer:
letter b should be the answer
What is occurring during the flat section of the graph below on the red arrow labeled boiling, between liquid and gas? gas (3.) OO liquid temperature solid time (minutes) O A. Heat is being absorbed, allowing particles of the liquid to overcome the atmospheric pressure. B. Heat is being absorbed, allowing particles of the liquid to overcome the vapor pressure. C. Heat is being released, allowing particles of liquid to overcome the pressure, and is why the temp does not increase. D. The temperature is no longer increasing even though heat is still being added because the heat is being absorbed to lower the melting point
with balanced chemical equations, show the different stages of fermentation
Answer:
formula for fermentation is: C6H12O6 → 2 C2H5OH + 2 CO.
Al wonders if adding salt to water will affect how long it takes the water to
freeze. Al thinks that salt water will freeze more quickly than fresh water.
He decides to check his hypothesis by conducting an experiment. Al takes
two ice trays and fills one with distilled water and the other with distilled
water that has two tablespoons of salt added. He makes sure he puts
exactly the same amount of water in each ice tray. Al takes the trays and
puts them side by side in the freezer. Al checks the ice trays every 10
minutes to see if the water in each tray has begun to freeze. Al finds that
after 20 minutes the water in the ice tray without the salt has started to
form ice, while the ice tray with the salt water is still completely liquid.
Ku
The hypothesis is that salt water freezes faster than fresh water.
The dependent variable is time taken for ice to appear.
The independent variable is presence or absence of salt
The constants are the amount of water in each tray, freezing conditions and length of time of exposure to freezing condition.
The control group is the tray to which salt was not added
The experimental group is the tray to which salt was added
The presence of solutes in a solution causes the freezing point depression.
A solution is made up of a solute and a solvent. In the presence of a solute, the freezing point of a pure solvent is decreased. This is because freezing point is a colligative property.
Colligative properties depend on the amount of solute present.
Hence, the pure water freezes faster (ice begin to appear earlier) than the salt water.
The hypothesis put forward in this experiment was found to be invalid by the experiment.
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What is the chemical formula for carbon tetrafluoride?
The Periodic Table
1
mono-
2
di-
3
4
tetra-
5
penta-
hexa-
6
7
hepta-
8
Oct-
9
nano-
10
deca-
PLS HELP!! WILL MARK BRAINLIEST! 99 POINTS!
You're going to first balance the chemical equation.
After that, convert the grams of Na into moles of Na, and then multiply that with the ratio of moles of NaCl to Na, and then convert the mol of NaCl into grams in order to obtain the theoretical yield, since we are given that Na is the limiting reactant.
After that, plug the values into the yield formula, doing some basic algebra, and you should get your result.
You're going to first balance the chemical equation.
After that, convert the grams of Na into moles of Na, and then multiply that with the ratio of moles of NaCl to Na, and then convert the mol of NaCl into grams in order to obtain the theoretical yield, since we are given that Na is the limiting reactant.
After that, plug the values into the yield formula, doing some basic algebra, and you should get your result.
Please help :)
A chocolate chip cookie recipe calls for 0.050 moles of baking soda (NaHCO3). How many grams should the chef mass out?
According to the mole concept, 4.2 g of baking soda should be weighed out.
What is mole concept?Mole is defined as the unit of amount of substance . It is the quantity measure of amount of substance of how many elementary particles are present in a given substance.
It is defined as exactly 6.022×10²³ elementary entities. The elementary entity can be a molecule, atom ion depending on the type of substance. Amount of elementary entities in a mole is called as Avogadro's number.
It is widely used in chemistry as a suitable way for expressing amounts of reactants and products.For the practical purposes, mass of one mole of compound in grams is approximately equal to mass of one molecule of compound measured in Daltons. Molar mass has units of gram per mole . In case of molecules, where molar mass in grams present in one mole of atoms is its atomic mass.
Baking soda has molar mass of 84 g /mole, thus mass is calculated using number of moles formula which is mass= molar mass×number of moles, which is mass=84×0.050=4.2 g.
Thus,4.2 g of baking soda should be weighed out by chef.
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Pesticides and fertilizers are a major cause of
O air pollution
O acid rain
o the greenhouse effect
O groundwater pollution
Answer:
it means air pollution Environment. The chemicals and nutrients found in fertilizers, while beneficial for agricultural crops, can be lethal in high doses for fish, birds and other wildlife. Pesticides, designed to kill pests chemically, are also dangerous when leached into soil or groundwater supplies.
Sodium is dissolved under kerosene oil or paroffin to protect it from the air. 3) State. Huckle's rule for aromaticity with example. How does benzene react with Chlorine in presense of Sun light
Answer:
His rule states that if a cyclic, planar molecule has 4n+2 π electrons
In the compound Ni2O3, nickel's oxidation number is_____
oxidation number is -2.
and oxygen's
Answer:
+3
Explanation:
The name of this compound would be nickel (III) oxide. Oxygen typically has a charge of -2. Given there are 3 oxygen atoms, that would equal a charge of -6. The nickel is the cation and must equal the charge of the anion, so must have a charge of +6. Since there are 2 nickel atoms, the charge on each must be +3.
Which statement best describes what happens as thermal energy from the
sun warms the pavement?
A. The thermal energy absorbed by the pavement is destroyed.
B. The thermal energy that is not absorbed by the pavement is
destroyed.
C. Some thermal energy is absorbed by the pavement, and some is
destroyed.
D. The thermal energy of the sun is transferred to the pavement.
Answer:
D
Explanation:
The correct answer would be that the thermal energy of the sun is transferred to the pavement.
Thermal energy refers to the internal energy possessed by a system by virtue of the movement of molecules within such a system. In other words, it is the heat energy possessed by a system.
When the thermal energy from the sun warms the pavement, it means that the thermal energy from the sun has been successfully transferred to the pavement. Thermal energy can be transferred by conduction, convection, or by radiation depending on whether the system is a solid, liquid, gas respectively.
The correct option is, therefore, D.
hurry
A solution:
A. is a mixture that is made when a solid dissolves and combines with a liquid.
B. is the amount of a substance that will combine with another substance before they begin to chemically combine.
C. is the amount of a substance that will dissolve in 1 dm3 of water at 25 C .
D. is two or more substances that are combined together but not chemically joined.
Reset Selection
Answer:
b is the correct answer ok
A solution is made up of solute and solvent. It is an addition of two or more substances to each other that combines physically and chemically. Thus, option B is correct.
What is a solution?A solution is the mixture of solutes that can be more than one in a solvent that has the same composition all over (homogenous). A solution comprises two main elements called a solute and a solvent.
A solute is the part of the solution that has been added to the solvent for desolvation. On the other hand, the solvent is the substance that dissolves the solute in them to make a solution.
The homogenous mixture or the solution can be created by mixing salt and water, sugar and water, mercury in amalgamated zinc, coffee, vinegar, etc.
Therefore, option B. a solution is the addition of the substances that combine physically.
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Which would increase the reaction rate?
O A. Decreasing the reactant concentrations
B. Removing heat from the system
O C. Adding a catalyst
O D. Lowering the value of k
Answer:
C
Explanation:
C. Adding a catalyst would increase the reaction rate.
What is a catalyst?A catalyst is a substance that increases the rate of a chemical reaction by lowering the activation energy required for the reaction to occur.
A catalyst enhances the probability of successful collisions between reactant molecules, which raises the pace of the reaction by offering an additional avenue for the reaction to occur.
As there would be fewer reactant molecules accessible to react with one another, decreasing reactant concentrations would result in a slower pace of reaction.
Due to the fact that chemical reactions often require energy to take place, eliminating heat from the system would also slow down the reaction rate. A lower value for k would result in a lower rate constant, which would lower the response rate.
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What's a third reaction? (Chemistry)
Explanation:
a chemical reaction in which the rate of reaction is proportional to the concentration of each of three reacting molecules
What is the order, plz answer
Answer:
C A B
Explanation:
come on, you also know this from normal water waves.
which ones are stronger (= have more energy) ? the small ones or the big ones ?
and the same applies to all waves. the bigger the waves (higher amplitude), the more energy.
A pupil has drawn the electronic structure of fluorine and the diagram is shown below. However,
mistakes have been made. State three mistakes that have been made.
The first shell can only hold 2 electrons, but the pupil placed in 8 electrons.
The second shell can hold up to 8 electrons, but the pupil only placed in 2 electrons.
Flourine only has 9 total electrons, yet there are 10 electrons in the diagram.
Answer:
Explanation:
In the Fluorine atom there are 2 electrons in the innermost shell and 7 i the outer shell.
(answered on edge)
Calculate the percent by mass of each element.
%N = 35 %
%H = 5.0 %
%O = 60 %
Answer:
N=35%. so 35/100*7 =2.45%
H=5.0 so 5/100*1=0.05%
o=60% so 60/100*8=4.8%
