A sample of radioactive material starts with 80 grams. After 3 half-lives have passed, how much radioactive sample remains?
Answer:
After 3 half lives 10 g of radio active material left.
Explanation:
Given data:
Total amount of radio active material = 80 g
Amount left after 3 half lives = ?
Solution:
At time zero = 80 g
At first half life = 80 g/2 = 40 g
At 2nd half life = 40 g/2 = 20 g
At 3rd half life = 20 g/2 = 10 g
Thus, after 3 half lives 10 g of radio active material left.
Pro
∆G0=-RT in k Known as
Answer:
Gibbs free energy equation
Explanation:
How many joules are required to melt 250 grams of water
Answer:
i not sure but i searched it up and it said Q=104525J
Explanation:
what is the molarity of a solution made by adding 0.720 mole of NaOH to 2.40 liters of water
Answer:
Molarity = 0.3 M
Explanation:
Given data:
Moles of NaOH = 0.720 mol
Volume of water = 2.40 L
Molarity = ?
Solution:
Molarity is used to describe the concentration of solution. It tells how many moles are dissolve in per litter of solution.
Formula:
Molarity = number of moles of solute / L of solution
Molarity = 0.720 mol / 2.40 L
Molarity = 0.3 mol/L
Molarity = 0.3 M
An ice cube melts on the warm sidewalk on a hot summer day. Let the entropies of the ice cube, of the pavement and of the ice cubesidewalk system be Sice, Ssw and Ssys. What happens to these entropies?
1. Sice increases, Ssw decreases, Ssys does not change.
2. Sice decreases, Ssw increases, Ssys decreases
3. Sice increases, Ssw decreases, Ssys increases
4. Sice increases, Ssw increases, Ssys increases
Answer:
3. Sice increases, Ssw decreases, Ssys increases
Explanation:
Entropy basically refers to the degree of disorderliness of a system.
Ice Cube --> As the ice cube melts, it undergoes a change in state of matter from solid to liquid hence it's entropy increases as the degree of movement of its molecules is more disordered in the liquid state.
This means the likely options are; 1, 3 and 4.
Sidewalk --> The entropy here decreases as the ice melts on the side walk. This is because there is a reduction in temperature. Entropy is directly proportional to temperature. Decrease in temperature leads to decrease in entropy.
This means the likely option is 1 and 3
The net entropy change of the system is however positive.
What is the electron configuration for N (nitrogen)?
A. 1s22s23s23p1
B. 1s21p5
C. 1s22s22p3
D. 1s22s22p23s1
Explanation:
₇N = 1s² 2s² 2p³
Group = 15period = 2atomic mass = 14Hydride of Nitrogen = Ammoniavalency = 3Therefore,
Option C is correct ✔
true or false the human body system works together to maintain
Answer:
Im pretty sure it would be true
Explanation:
Explain how atoms organize to create larger structures?
Answer:
First of all they are super tiny particles of neutrons, electrons and protons. Then they come together to organize a structure of atom. Atoms come together to form a molecule and smaller molecules work together to form macromolecules. Thus, how they organize and form building blocks of a substance.
Hope it helps!<3
Polonium-214 went through a series of radioactive decays to produce a stable isotope of bismuth-210 choose the correct decay series that would produce bismuth-210
A: Polonium-214 undergoes 2 beta decay and 1 gamma emission
B: Polonium-214 undergoes 1 alpha decay and 2 gamma emission
C: Polonium-214 undergoes 2 alpha decay and 1 beta decay
D: Polonium-214 undergoes 1 alpha decay 1 beta decay and 1 gamma emission.
The correct decay series :
₈₄Po²¹⁴⇒₈₃Bi²¹⁰+₂He⁴+ ₋₁e⁰+ ₀γ⁰
Further explanationRadioactivity is the process of unstable isotopes to stable isotopes by decay, by emitting certain particles,
alpha α particles ₂He⁴ beta β ₋₁e⁰ particles gamma particles ₀γ⁰ positron particles ₁e⁰ neutron ₀n¹Decay's reaction :
₈₄Po²¹⁴⇒₈₃Bi²¹⁰+x+y+z
From this decay reaction can be concluded
mass number decreased by 4
atomic number decreased by 1
Then the most suitable are:
Polonium-214 undergoes 1 alpha decay 1 beta decay and 1 gamma emission.
₈₄Po²¹⁴⇒₈₃Bi²¹⁰+₂He⁴+ ₋₁e⁰+ ₀γ⁰
So that the mass number and atomic number are the same both before and after decay
A metal ion uses d2sp3 orbitals when forming a complex. What is its coordination number and the shape of the complex?
Answer:
Octahedral
Explanation:
The idea of hybridization is a valence bond concept introduced by Linus Pauling and soon became an important explanation for the structure of molecules even in coordination chemistry.
Hybridization involves the mixing of orbitals of appropriate energy to form a new set of orbitals that are more suitable for bonding with ligands.
When one s, two d and three p orbitals are hybridized in complex formation, octahedral complexes are formed.
The red outlined elements have what major characteristics in common?
1 point
Metals, Nonmetals, and Metalloids
One major characteristic they have in common is they are metals.
what is made from a chemical reaction?
Answer:
the Product
Explanation:
Percent yield is very important in terms of money. The higher the percent yield, the more of a product you can make. If you are working for a drug company and your theoretical yield is 120 kg, but you actually made 105 kg, what is your percent yield?
A. 8.75%
B. 114%
C. 87.50%
D. 15.00%
Answer:
87.5 %
Explanation:
Step 1: Given data
Theoretical yield: 120 kgReal yield: 105 kgStep 2: Calculate the percent yield
When working with chemical reactions, we can determine the efficience in obtaining a product measuring the percent yield. The theoretical yield is the maximum amount of product that we could obtain according to the stoichiometry, whereas the real yield is the amount of product that we actually obtain when we carry out the process. We can calculate the percent yield usign the following expression.
%yield = real yield / theoretical yield × 100%
%yield = 105 kg / 120 kg × 100%
%yield = 87.5 %
Write the formula for diphosphorous pentoxide
Answer:
P4O10
Explanation:
These allow electricity to flow easily through them (think copper and aluminum).
(Lessons 5.01-5.03)
Insulators
Electric Currents
Conductors
Resistors
Answer:
conductors
Explanation:
How does mass affect a star's life cycle?
O A.
The greater a star's mass, the more likely it is to burn forever.
O B.
The greater a star's mass, the more likely it is to form planets.
O c.
The greater a star's mass, the more likely it is to fuse hydrogen.
D.
The greater a star's mass, the more likely it is to become a black hole.
Answer:
A star's life cycle is determined by its mass. The larger its mass, the shorter its life cycle. A star's mass is determined by the amount of matter that is available in its nebula, the giant cloud of gas and dust from which it was born. ... As the gas spins faster, it heats up and becomes as a protostar.Explanation:
Read this and then choose your options ✍️✍️Rocks melt at what temperature range? a. 50 to 100 degrees Celsius b. 130 to 200 degrees Celsius c. 220 to 500 degrees Celsius d. 600 to 1,300 degrees Celsius
600 and 1,300 degrees Celsius
In pretty sure
How many mL of 0.125 M Ba(OH)2 would be required to completely neutralize 75.0 mL of 0.845 M HCl? What is the pH of the solution at the equivalence point?
Answer:
253.5mL of Ba(OH)₂ are required to neutralize the HCl solution
The pH at equivalence point is = 7
Explanation:
The reaction of Ba(OH)₂ with HCl is:
Ba(OH)₂ + 2HCl → BaCl₂ + 2H₂O
First, we need to find moles of HCl. With these moles and the chemical equation we can find the moles of Ba(OH)₂ and the volume required:
Moles HCl:
75.0mL = 0.075L * (0.845mol / 1L) = 0.063375moles HCl
Moles Ba(OH)₂:
0.06338moles HCl * (1mol Ba(OH)₂ / 2mol HCl) = 0.03169 moles Ba(OH)₂
Volume of the 0.125M Ba(OH)₂:
0.03169 moles Ba(OH)₂ * (1L / 0.125mol) = 0.2535L are required =
253.5mL of Ba(OH)₂ are required to neutralize the HCl solution
As the titration was of a strong acid, HCl, with a strong base, Ba(OH)₂, the pH at equivalence point is = 7
A sample of an unknown compound is vaporized at 150.°C . The gas produced has a volume of 960.mL at a pressure of 1.00atm , and it weighs 0.941g . Assuming the gas behaves as an ideal gas under these conditions, calculate the molar mass of the compound. Round your answer to 3 significant digits.
Answer:
the molar mass of the compound is 34.0 g /mol
Explanation:
The computation of the molar mass of the compound is as follows:
As we know that
PV = nRT
n = mass ÷ MW
PV = mRT ÷ MW
It can be rearrange as
MW = mRT ÷ (PV)
MW = (0.941)(0.082)(150 + 273) ÷ (1 × 0.96)
= 33.99g/mol
= 34.0 g /mol
Hence, the molar mass of the compound is 34.0 g /mol
What is the total charge of an iron nucleus
A candle made of certain wax blend burns at a rate of 44.2 mg/min. What is the value of this burn rate if expressed in grams/hour
Answer:
2.652 g/h.
Explanation:
Burn rate (in mg/min) = 44.2 mg/min
Burn rate (in m/h) =?
We'll begin by converting 44.2 mg/min to g/min. This can be obtained as follow:
1 mg/min = 0.001 g/min
Therefore,
44.2 mg/min = 44.2 mg/min × 0.001 g/min / 1 mg/min
44.2 mg/min = 0.0442 g/min
Finally, we shall convert 0.0442 g/min to g/h. This can be obtained as follow:
1 g/min = 60 g/h
Therefore,
0.0442 g/min = 0.0442 g/min × 60 g/h / 1 g/min
0.0442 g/min = 2.652 g/h
Therefore, 44.2 mg/min is equivalent to 2.652 g/h.
Thus, the burn rate (in m/h) is 2.652 g/h.
A 12.0% sucrose solution by mass has a density of 1.05 gem, what mass of sucrose is present in a 32.0-mL sample of this solution?
A) 0.126g
B) 3.66g
C) 4.03g
D) 3.84g
E) 280 g
Answer:
Option C. 4.03 g
Explanation:
Firstly we analyse data.
12 % by mass, is a sort of concentration. It indicates that in 100 g of SOLUTION, we have 12 g of SOLUTE.
Density is the data that indicates grams of solution in volume of solution.
We need to determine, the volume of solution for the concentration
Density = mass / volume
1.05 g/mL = 100 g / volume
Volume = 100 g / 1.05 g/mL → 95.24 mL
Therefore our 12 g of solute are contained in 95.24 mL
Let's finish this by a rule of three.
95.24 mL contain 12 g of sucrose
Our sample of 32 mL may contain ( 32 . 12) / 95.24 = 4.03 g
Middle school science help please. ill give brainliest
Answer:
It converts The liquid into a gas at the same temperature.
Explanation:
Answer:
it converts the liquid into gas at the same temperature
Explanation:
when heat is added to a liquid at boiling temperature it converts the liquid into gas at that same boiling temperature
please give brainliest
An element has three isotopes. The masses and % abundances for the isotopes are: Isotope #1 mass 38.96 amu, % abundance=93.26%, Isotope #2 mass
39.96 amu, % abundance 0.012 %, and Isotope #3 mass= 40.96 amu, % abundance=6.73 %. The average atomic mass for this element has to be
Answer:
39.095
Explanation:
this is because all this isotopes belong to a single element thus
(38.96×93.26)+(39.96×0.012)+(40.96×6.73)
answer of that divided by 100%
If 18.00 mL of 0.1000 M magnesium hydroxide reacts with 10.00 mL of hydrochloric acid, what is the molarity of the acid solution?
Answer:
0.36M HCl
Explanation:
The reaction of Mg(OH)₂ with HCl is:
Mg(OH)₂ + 2HCl → MgCl₂ + 2H₂O
Where 1 mole of magnesium hydroxide reacts with 2 moles of HCl
To solve this question, we need to find the moles of Mg(OH)₂ that reacted and, with chemical equation, solve for the moles of HCl and its molarity (Using the 10.00mL = 0.01000L) as follows:
Moles of Mg(OH)₂:
18mL = 0.018L * (0.100mol / L) = 0.0018 moles Mg(OH)₂
Moles HCl:
0.0018 moles Mg(OH)₂ * (2 moles HCl / mol Mg(OH)₂) = 0.0036 moles HCl
Molarity HCl:
0.0036 moles HCl / 0.0100L =
0.36M HClWhich of the following statements is true?
Question 10 options:
a chromosome is larger than a cell
a DNA strand is made of many chromosomes
a gene contains may chromosomes
a chromosome contains many genes
Answer:
a chromosome contains many genes
Explanation:
#1...TRUE/FALSE, the best way to write a conclusion is to use the RERUN method.?
#2...TRUE/FALSE, an example of an inference is “I saw it rain today.”?
#3...TRUE/FALSE, an example of a quantitative observation is “That is a red doll.”?
#4...TRUE/FALSE, a scientific hypothesis is written as “If [independent variable] Then [dependent variable.]”?
please answer all of them
How many moles are in the 100,000g of CuSO4 • 5H2O ?
Answer:
try (107.87 amu)
Explanation:
A compound with a formula mass of 45.08 g/mol is found to be 85.64% Carbon and the remainder Hydrogen. Find the molecular formula:
What do you have to do to break a molecule?
Answer:
Heat the molecule
Explanation:
Since most bonds require energy to form, they also give off energy when they are broken. But before most bonds break, the molecule has to be heated. Then the atoms start to move, and when they move too much, the bond breaks. Molecules that require less energy to break than they give off when broken are called fuels.
