The number of half-lives that has elapsed since the sample originally formed is 3 half-lives
Data obtained from the questionOriginal amount (N₀) = 15.4 + 2.2 = 17.6 g
Amount remaining (N) = 2.2 g
Number of half-lives (n) = ?
How to determine the number of half-lives that has elapsed2ⁿ = N₀ / N
2ⁿ = 17.6 / 2.2
2ⁿ = 8
2ⁿ = 2³
n = 3
Thus, 3 half-lives has elapsed
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Answer:
3
Explanation:
e2022
Dominic and Eva are using the same type of stopwatches to measure the time it takes for a chemical reaction to occur. They each use the same stopwatch to measure the time. These are their results:
Person Trial 1
Dominic 78 seconds
Eva 81 seconds
Why are their results unreliable and can lead to a pseudoscientific claim?
They did not repeat their tests multiple times.
They used the same type of stopwatch.
They did not change the reactants in their chemical reactions.
Only one person should have collected the data.
Base your answer to the question on the information below given the reaction at equilibrium2NO2(g)+7H2(g)->-< 2NH3(g)+4H2O(g)+1127kJ which diagram below correctly shows the potential energy diagram for the forward reaction, including the activation energy and the potential energy of the products?
Answer: 1
Explanation:
Heat is being released, so the energy of the reactants is less than the energy of the products.
42. Balance the equation below. What is the coefficient for HCI?
Help me please don’t answer then delete I will report u
Answer:
Mg + 2HCl ⇒ MgCl₂ + H₂Coefficient of HCl = 2Explanation:
Equation (given) :
Mg + HCl ⇒ MgCl₂ + H₂Compare the LHS and RHS :
On the left side, there are only single atoms of H and Cl, whereas there are 2 of each on the right sideAs HCl is a single compound on the left, multiply HCl into 2 to balance the reactionCoefficient of HCl = 2Balanced Equation :
Mg + 2HCl ⇒ MgCl₂ + H₂What is the Mass of 1 mole of N2? Show your work
Answer:
28 g/mol
Explanation:
since the atomic weight of Nitrogen is 14 you take the amount of it and multiply it by that so in this case it would be this equation:
14 x 2 = 28
How many ml of naoh was used to reach the equivalence point?
options:
10ml
20ml
25ml
50ml
What is the difference between ethanol and methanol.
NaOH (aq) + CuSO4(aq) →
balance the equation.
The elements of a group have the same number of ___________________ in their ______________ shell
Answer:
Same amoung of electrons in their outer shell
Explanation:
elements in the same group have the same number of electrons in their outer shell this is why they are in the same group
The elements of a group have the same number of valence electrons in their outermost shell.
Why do the elements of the same group have similar chemical behavior?The chemical properties of elements are described by the number of valence electrons in their outermost shell. The chemical elements placed in the same group have the same number of valence electrons in their valence shell. Therefore, the chemical elements placed in the same group of the periodic table have similar chemical behavior.
The elements having identical valence electronic configurations in their atoms are arranged in the same group of the modern periodic table. These valence electrons are accountable for the chemical properties and reactivities of the elements.
For example, the chemical properties of all elements in group 1 are similar as they have only one electron in their valence shell. The chemical elements of group 17 have seven electrons in their valence shell they are halogens with similar chemical behavior.
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The attraction of hydrogen to oxygen in a water molecule has unequal sharing of electrons, caused by a(n) _____.
A. metallic bond
B. nonpolar covalent bond
C. covalent bond
D. ionic bond
E. polar covalent bond
Answer:
c
Explanation:
got it right on my test
Answer:
The answer is: C aka covalent bond
Explanation:
Happy to help
Select all the following solutions that would be expected ph values for basic solutions?
ph 7
ph 9
ph 12
ph 5
ph 10
Answer:
9, 10, 12
Explanation:
anything greater than pH 7 is basic
A 28. 0 ml sample of vinegar, which is an aqueous solution of acetic acid, ch3cooh, requires 21. 5 ml of 0. 550 m naoh to reach the endpoint in a titration
Concentration of vinegar sample of 28mL which requires 21. 5 ml of 0.550 M NaOH to reach the endpoint in a titration is 0.42M.
How do we calculate the concentration of Vinegar?Concentration of vinegar in the titration method will be used by using the below equation:
M₁V₁ = M₂V₂,
M₁ & V₁ are the molarity and volume of acetic acid.M₂ & V₂ are the molarity and volume of vinegar sample.By putting values on above equation from the question, we get
M₂ = (0.55M)(21.5mL) / (28mL) = 0.42 M
Hence, required concentration of vinegar is 0.42M.
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please help, will give brainliest
Answer:
See explanations and answers below
Explanation:
From the equation each mole calcium bromide makes 2 moles sodium bromide
1) 5 x 2 = 10 moles sodium bromide
2) 2 moles of calcium bromide will make 2 moles of calcium sulfate ( from the equation)
mole weight of calcium sulfate =
Ca = 40 S = 32 O4 = 64 total mole weight = 136 gm
two moles would weigh 272 gms
3) 845 gm of calcium sulfate is 845 gm / 136 gm/mole = 6.21 moles
6.21 moles of Ca Br2 will be needed
6 .21 ( 40 + 2 *79.9) = 1240.76 gm
Acids which contain only hydrogen and a single other element are referred to as.
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A binary acid is an acid that consists of hydrogen and one other element.How many atoms in Ga2Se3
In a reaction the ->
means
Answer:
the arrow (single arrow) means that all the reactants are going to products.
salt seems to disappear when it is poured into water use the terms mixture solution and dissolve to explain what happens
Answer:
water acts as a solvent and dissolves the solute (salt) to produce a salt water solution
Explanation:
How many milliliters of a 0.1000 M NaOH solution would be needed to neutralize a 1.0000-g sample of potassium hydrogen phthalate (KHC8H4O4) to a phenolphthalein endpoint, according to the following balanced equation?
KHC8H4O4(s)+NaOH(aq)------> KNaC8H4O4(aq)+H2O(l)
Answer: 2) 2HCl(sq) + CaCO3(s) CaCl2(sq) + CO2(g) + H2O (l) No of moles of CaCO3 = amount of the CaCO3 (g)/mw of CaCO3 (g/mole)= 0.8085 g/100 g/mole = 0.008085
Explanation:
When ammonium chloride is dissolved in water, the beaker gets cold. Which type of reaction does this describe?
exothermic
endothermic
both exothermic and endothermic
neither exothermic nor endothermic
32
How many moles of Ca(NO) are there in a sample with a mass of 50.0 g?
a. 0.305 mol
b. 0.333 mol
c.
0.490 mol
d. 8200 mol
Answer:
0.305 mol
Explanation:
Ca(NO) is not a molecule. I think you meant to type Ca(NO3)2, which is calcium nitrate.
The moles of a compound is equal to is mass divided by its molar mass.
The molar mass of Ca(NO3)2 is 164.09 g/mol.
50.0 / 164.09 = 0.305
A gas at 200 Celsius and 10.0L expands to 20.0L. What is the new temperature in Celsius
Answer:
400celcius
Ex:
200 per 10.0L
400 per 20.0L
Most scientists use scientific methods in which of the following orders
Answer:
Experiment, analysis, research, purpose, hypothesis and conclusion.
What does the shape of the moon we see depend on?
The position of the moon during its orbit around Earth
The position of the moon during its orbit around Jupiter
The position of the moon during its orbit around Mars
The position of the moon during its orbit around Saturn
Answer:
The position of the moon during its orbit around Earth
Answer:
the angle you look at it from
How many moles of carbon dioxide are produced if 50.0 L of oxygen is used?
If a reactant is in excess, why do we not worry about the mole ratios involving that reactant?.
Answer: The limiting reactant will be used up first, meaning the reaction can no longer occur with only the excess reactant.
Explanation:
In a reaction the reactant which determines the yield of the reaction is called limiting reactant. Whereas, the reactant which is excess in amount does not itself lead the reaction after the limiting reactant is consumed.
What is excess reactant?In a reaction, the yield of the product depends on the number of moles of reactants. The reactants which is not sufficient in amount is determining the yield because as soon as this reactant is consumed, the production stopes.
The excess reactant on the other hand is excess in amount which can't lead the reaction alone after the consumption of the limiting reactant. Hence, we don't have to worry on the excess reactant.
The limiting reactant of a reaction can be determined by calculating the number of moles of each reactants participating in it.
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- 35. Which of the following processes are exo- thermic? Endothermic?
What is the pH of a solution whose [H⁺] is 2.7 x 10⁻⁴ M?
Answer:
Here is the solution..Hope it helps:)
A 2.75 M solution is diluted to 0.706 M, if the starting volume was 0.833L, what is the new volume?
Answer:
3.2447
Explanation:
m1v1 = m2v2
what was the significance oh Rutherford's expierment
Answer:
His gold foil experiment showed that the atom is mostly empty space with a tiny dense positively-charged nucleus. Based on those results, Rutherford was able to propose the nuclear model of the atom.
You've found some fossil bones while digging in your backyard. Could they be dinosaur bones? Using carbon dating, you determine that 3% of the original radioactive carbon-14 is still radioactive. (The rest has decayed into nitrogen-14.) How many half-life cycles has it gone through?
The half-life of Carbon-14 is 5730 years. When did the animal die?
Answer:
5 is the first answer and 28,650 for second
Can I get help in #6 ?
option A Hydrogen will have the greatest rate of effusion beacuse it has the least mass among all
