Answer:
Mass extinctions happen because of climate change, asteroid impacts, massive volcanic eruptions or a combination of these causes.
Explanation:
If a radioactive source has a half life of 2 hours how long will it take for the activity to go from 200 to 25?
Answer:
It takes 6h to the radioactive source decrease its activity from 200 to 25
Explanation:
The equation that describes the readioactive decay is:
Ln [A] = -kt + Ln [A]₀
Where [A] could be taken as activity of the source after time t, [A]₀ is initial activity and k is decay constant.
Decay constant could be written as:
k = ln2 / Half-life
k = ln 2 / 2h
k = 0.3466h⁻¹
Replacing in decay equation:
Ln [25] = -0.3466h⁻¹t + Ln [200]
-2.0794 = -0.3466h⁻¹t
6h = t
It takes 6h to the radioactive source decrease its activity from 200 to 25
What are two properties that make a metal a good choice to use a wire in electronics? *
Answer:
Explanation:
The two properties that make a metal a good choice to use a wire in electronics are :
ductility conductivityCan someone please help
Answer:
Water is the answer
Explanation:
How many liters of hydrogen are required to react completely with 2.4L of oxygen to form water? 2H2 + O2 --> 2H2O
Answer:
2.4 mole of oxygen will react with 2.4 moles of hydrogen
Explanation:
As we know
1 liter = 1000 grams
2H2 + O2 --> 2H2O
Weight of H2 molecule = 2.016 g/mol
Weight of water = 18.01 gram /l
2 mole of oxygen react with 2 mole of H2
2.4 mole of oxygen will react with 2.4 moles of hydrogen
Thomas sits half way down a grassy slope. What force stopped him slamming down
In order to produce CO2, a student put a sample of calcium carbonate in a flask and added hydrochloric acid using the following equation: Ca(CO3) + HCl → H2O + CO2 + CaCl2 The student finds the mass of CO2 generated to be 100 g. If the student began with 200 g of HCl and there was ample CaCO3 left unreacted, what was the percent yield?
Answer:
82.9% Is the percent yield
Explanation:
First, we need to balance the equation.
Ca(CO3) + 2HCl → H2O + CO2 + CaCl2
Since the problem tells you that the excess reactant is Ca(CO3), we just need to Stoichiometry to solve for the theoretical yield.
[tex]\frac{200g HCl}{1}[/tex] x [tex]\frac{1 mole HCl}{36.46gHCl}[/tex] x [tex]\frac{1 mol CO2}{2molHCl}[/tex] x [tex]\frac{44.01CO2}{1molCO2}[/tex] =120.707 g (theoretical yield)
Take your actual yield of 100g, divide that by 120.707, then multiply that decimical by 100.
Which type of plate boundary is associated with seafloor spreading at the source of the spread: convergent, divergent, or transform?
Answer:
The answer is divergent
What season is it in earths northern hemisphere when earths northern hemisphere tilts toward the sun
Answer:
Summer
Explanation:
Earth's tilted axis causes the seasons. Throughout the year, different parts of Earth receive the Sun's most direct rays. So, when the North Pole tilts toward the Sun, it's summer in the Northern Hemisphere. And when the South Pole tilts toward the Sun, it's winter in the Northern Hemisphere.
Hope it helped!! Please mark as Brainliest!
Answer:
Summer took the test and got it right
Explanation:
Which season will the northern hemisphere experience when the axis of Earth is tilted towards the sun?
Summer
Calculate the amount of work done in lifting a heavy load of 50kg up to the height of 3m?
amount of work done is equal to l/h
so 50/3=16.66667
round your ans to 2 significant figure
so your ans will be 17m/kg
when gas changes to liquid is it gaining or loosing energy?
Answer:
Loosing energy
Explanation:
As the particles movement in gas slows down further when it is cooled
What is the percent of oxygen in C6H12O6?
Answer and Explanation:
C6 H12 O6=6×16=96g/mol
96/180×100=53%
Question 19 Multiple Choice Worth 3 points)
(06.04 MC)
What forensic scientist established the 'Body Farm' to study the ways bodies decompose under different circumstances?
Matheiu Orfila
Sir Edward Henry
Phillipe Locard
Bill Bass
Answer:
The answer is D Bill Bass
Explanation:
Remember it from the lesson and I took the test.
A person riding a bike has a mass of 55kg. They are moving with a velocity of 2m/s. What is the Kinetic Energy of the person?
Explanation:
Formula : ½ × mv² (mass×velocity)
½ × 55 × 2²= ½×55×4=110J
(½ is also equivalent to 0.5)
J = Joules
How many atoms of cobalt are in 4 moles of cobalt?
2 × 10²⁴ atoms Co
General Formulas and Concepts:Math
Pre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to RightChemistry
Atomic Structure
Reading a Periodic TableAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Stoichiometry
Using Dimensional AnalysisExplanation:Step 1: Define
4 mol Co (Cobalt)
Step 2: Identify Conversions
Avogadro's Number
Step 3: Convert
Set up: [tex]\displaystyle 4 \ mol \ Co(\frac{6.022 \cdot 10^{23} \ atoms \ Co}{1 \ mol \ Co})[/tex]Multiply/Divide: [tex]\displaystyle 2.4088 \cdot 10^{24} \ atoms \ Co[/tex]Step 4: Check
Follow sig fig rules and round. We are given 1 sig fig.
2.4088 × 10²⁴ atoms Co ≈ 2 × 10²⁴ atoms Co
You live 10.13 km from school. Convert kilometres to meters.
Answer:
10130
Explanation:
there are 1000 m in a km
Answer:
10130 meters
Explanation:
What coefficient should go in front of the hydrogen peroxide (H2O2 ) molecule to make the chemical equation balanced? ___ H2O2 ➞ 2 H2O + O2
Answer:
2
Explanation:
H2O2 ➞ 2 H2O + O2
The reaction is currently not balanced because the number of atoms on the reactant side is not equal to that of the product side
Hydrogen
Reactant = 2 Product = 4
Oxygen
Reactant = 2 Product = 4
Adding 2 to H2O2 balances the reaction as the number of atoms of both elements are now balanced on both sides of the equation
2H2O2 ➞ 2 H2O + O2
A student says that since the atomic theory is just a theory, it should not be considered useful. Which
statement best argues against the student's opinion? (2 points)
O Scientific theories change over time.
O Scientists often do not agree about specific details of scientific theories.
O Scientists often propose competing theories.
O Scientific theories do not become Scientific Laws.
O Scientific theories are the results of many experiments and observations.
Answer:
O Scientific theories are the results of many experiments and observations.
Explanation:
Going through the options;
O Scientific theories change over time.
This is true and supports the student's opinion. So wrong option!
O Scientists often do not agree about specific details of scientific theories.
This is true. However, it supports the student's opinion. So wrong option!
O Scientists often propose competing theories.
This is true. However, it supports the student's opinion. So wrong option!
O Scientific theories do not become Scientific Laws.
This is False. Theories that have withstood the test of time and countless experiments become laws. However it support's the student's opinion. So wrong option!
O Scientific theories are the results of many experiments and observations.
This is true and is against the student's opinion. This option is correct!
How many grams are in 0.75 moles of Fe
Answer:
41.88375 g Fe
Explanation:
Using stoichiometry, we can do this problem. First, we put our given. Then we create an equation using the molar mass of Fe (found on the periodic table, which was 55.845 g Fe), and the resulting equation is:
[tex]0.75 mol Fe * \frac{55.845 g Fe}{1 mol Fe}[/tex]
The mol Fe's cancel, and leave us with:
41.88375 g Fe
Good luck.
A cup of coffee is made in the morning by pouring water ov er ground up coffee beans in a piece of paper and by collecting the brown liquid that comes through. Which techniques used
Answer: Filtration technique
Explanation:
The technique used here is called filtration.
Filtration,is a physical separation process that separates a mixture of an insoluble solid from a liquid ( acting as the solvent) by the use of a filter barrier that allows only the fluid to pass through.
In the case from the question,
As water is poured over the ground coffee, it forms a mixture of which the insoluble solid is the coffee grounds, the water is the liquid and the filter barrier is the piece of paper which allows only the brown liquid coffee to pass through as the filtrate.
How does water pressure relate to depth?
This image models…
diffraction
reflection
refraction
absorption
Answer:
reflection is correct answer by my views
Plants cannot grow too close together because their Blank______ need to spread out and absorb nutrients from the soil.
their roots need room to spread out
can we stir silver nitrate solution with copper spoon? why or why not? support your answer with reason.
↪ Hello miss "galaxyu035" here's your answer for the question you wrote.
Answer :
No, we cannot stir silver nitrate solution with a copper spoon because , copper is more reactive than silver. Thus,it would displace silver from the silver nitrate solution forming copper nitrate.
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Remember if my answer helps you! Might give me a thank you! By clicking the heart button .
A violent disturbance in the atmosphere is a
eye of hurricane
surge
front
storm
Answer: Storm surge
Explanation:
someone please help... ill give you a heart a five star rating and the brainliest answer
Has anyone done this???!!!
Answer:
top one is anaphase and the middle one is cytokinesis can't see enough of the bottom one to tell
Explanation:
Change 60. miles/hour to km/min?
Based on the table above, which amount of a compound dissolved in 100 grams of water at the stated temperature represents a system at equilibrium?
Select one:
a. 40 g NaCl at 70 degrees Celsius
b. 20 g KClO3 at 70 degrees Celsius
c. 80 g NaNO3at 10 degrees Celsius
d. 80 g Pb(NO3)2 at 30 degrees Celsius
Answer:
C. 80g Nano3 at 10 degrees Celsius
Explanation:
I just took the test
80 g NaNO₃ at 10 degrees Celsius of a compound dissolved in 100 grams of water at the stated temperature represents a system at equilibrium. Therefore, option C is correct.
What is solubility ?The maximum quantity of a chemical that will dissolve in a given amount of solvent at a particular temperature is referred to as its solubility.
Different compounds have very varying solubilities, which is a feature of a particular solute-solvent pair.
A substance's physical and chemical characteristics affect how soluble it is. A few other factors and circumstances can also influence it. A few of these are: temperature, pressure, kind of binding, and forces between the particles.
A system is said to be in equilibrium when 80 grammes of a substance, dissolved in 100 grams of water at 10 degrees Celsius.
Thus, option C is correct.
To learn more about the solubility, follow the link;
https://brainly.com/question/28170449
#SPJ2
1 Atoms of the same element with different numbers of neutrons are defined as:
o
neutrons
O
isotopes
O
elements
O
compounds
Answer:
The answer is B Isotopes
6) The following questions refer to F2 and Cl2.
a. Draw the molecular model (space-filling or ball-and-stick) that would
provide the best means for comparing the differences in bond length and
bond energy.
b. Which structure has the longest bond length? Justify your answer.
c. Which bond has the greatest bond energy? Justify your answer.
d. Which structure has the least potential energy associated with its bond?
Justify your answer.
Answer:
chill
Explanation: