A sample of radioactive material starts with 80 grams. After 3 half-lives have passed, how much radioactive sample remains?
Answer:
I want to say 10 grams
Explanation:
80 grams is your start
and a half-life is half of that so...
half of 80 ( and or 80/2)
40 grams
then another half is...
half of 40 (and or 40/2)
20 grams
then another half-life is...
half of 20 (and or 20/2)
10 grams
That is 3 half-life of 80 grams
*becareful not to just divide 80 / 3 you will get 26.666 (repeating) that is incorrect
you want a half of a half of a half
velocity is a ______ quantity
Answer:
vector quantity
Explanation: Brainliest pls
how many moles of NO are formed from 2.5 moles of NO2 if there is plenty of water present
Moles of NO formed : 0.833
Further explanationGiven
2.5 moles of NO2
Required
moles of NO formed
Solution
Reaction
3 NO₂(g) + H₂O(l) = 2 HNO₃(aq) + NO(g)
The reaction coefficient in a chemical equation shows the mole ratio of the compounds in the reactants and products
From the equation, mol ratio of NO₂ and NO = 3 : 1, so moles of NO :
[tex]\tt moles~NO=\dfrac{1}{3}\times 2.5\\\\moles~NO=0.833[/tex]
For the reaction below, if the rate of appearance of Br2 is 0.180 M/s, what is the rate of disappearance of
NOBr?
2 NOBr(g) → 2 NO(g) + Br2(g)
a. –0.360 M/s
b. –0.090 M/s
c. 0.090 M/s
d. 0.180 M/s
e. 0.720 M/s
Answer:
–0.360 M/s
Explanation:
I NEED TO KNOW THIS ASAP
Answer:
I think that the answers A, not 100% sure tho
Explanation:
Because the problem says "highly radioactive" chemicals and gamma rays are highly radioactive chemicals, and gamma rays are very penetrating to the human body
Spheres of Earth Assignment Active Analyzing Sphere Interactions Explain how Earth's spheres may be affected by the droughts brought on by El Niño. Sometimes, the surface of the Pacific Ocean warms up, causing changes in the weather in some areas. This phenomenon is called El Niño. El Niño causes the amount of rainfall in some parts of the United States and South America to increase. It also causes droughts to occur in Southeast Asia and Australia. Droughts occur when an area receives less rain than it normally does over a certain period.
help me on this question please. it is 7th grade science
Write out the electron configurations of the ions below and determine which one is listed with an incorrect charge. (the numbers and charges written after the elemental symbol should be understood as superscripts)
A. I-
B.O2+
C. Al3+
D. Mg2+
E. none of the above
Answer:
I think B. O2+
Explanation:
Answer:
B
it must be O2- not O2+, because it's an anion not a cation.
true or false A force can change the shape of an object.
Answer:
True
Explanation:
When a force acts on an object, the object may change shape by bending, stretching or compressing - or a combination of all three shape changes.
Why is light a wave?
Answer:
an electromagnetic wave
Explanation:
Help DUE MONDAY!!!
Dldm
Time to slide down : 2.4 s
Further explanationGiven
total length of slide = 12 m
Randy's speed = 5 m/s
Required
time to slide down
Solution
Randy's motion can be said to be a straight, regular motion at a constant speed
Can be formulated
d = v x t
d = distance, m
v = velocity, m / s
t = time, s
we plug in the known values in the formula
[tex]\tt t=\dfrac{d}{v}\\\\t=\dfrac{12~m}{5~m/s}\\\\t=2.4~s[/tex]
To create an image, the lens of an eye ________
focuses light on the cornea
reflects light away from the retina
bends the cornea to correct vision
focuses light on the retina
Answer:
focuses light on the retina
Explanation:
Q 16.1: Select the first step in the Wittig reaction. A : The alkyltriphenylphosphonium halide is deprotonated by a base to make a phosphorus ylide. B : The phosphorus ylide reacts with the aldehyde or ketone to make an oxaphosphetane. C : Triphenylphosphine attacks the alkyl halide to produce an alkyltriphenylphosphonium halide. D : The oxaphosphetane decomposes to form the alkene and triphenylphosphine oxide.
Answer:
The phosphorus ylide reacts with the aldehyde or ketone to make an oxaphosphetane.
Explanation:
The Wittig reaction is a reaction that occurs between a phosphorus ylide and an aldehyde or ketone. The final products are an alkene and triphenyl phosphine oxide.
The first step in the reaction is the attack of the phosphorus ylide on the aldehyde or ketone. This is followed by attack of oxygen on phosphorus to form a [2+2] cycloaddition product (oxaphosphetane) which decomposes to form the alkene and triphenylphosphine oxide.
5x10-6 mol Na2C2O4 bileşiğinde kaç tane O atomu vardır?
How many oxygen atoms are present in 5x10-6 mol Na2C2O4 ?
There are 1.204 x 10¹⁹ atoms O
Further explanationThe empirical formula is the smallest comparison of atoms of compound forming elements.
A molecular formula is a formula that shows the number of atomic elements that make up a compound.
1 mol of molecule Na₂C₂O₄ :
There are 4 mol of O in 1 mol of molecule Na₂C₂O₄
So for 5 x 10⁻⁶ mol Na₂C₂O₄ :
[tex]\tt mol~O=4\times 5.10^{-6}=2.10^{-5}[/tex]
1 mole = 6.02.10²³ particles , so number of atoms O :
[tex]\tt 2\times 10^{-5}\times 6.02\times 10^{23}=1.204\times 10^{19}[/tex]
What is immigration and emigration
Answer:
well for me I think
Explanation:
immigration is the movement which involves an individual moving from a present place to another environment
That is going out
WHILE
Emigration is the process where a person comes into a particular environment
That means coming in
Question 1 (3 points)
(01.01 LC)
Which of the following objects will exert the greatest gravitational force on a box, if the distance between them remains the same? (3 points)
Оа
2 kg mass
Ob
4 kg mass
Ос
6 kg mass
8 kg mass
The following objects will exert the greatest gravitational force on a box⇒ 8 kg mass
Further explanationGravity is a force that arises because of the attraction between objects with mass.
The magnitude of this attraction is proportional to the mass of the object.
The greater the mass of the object, the greater the gravitational force
Relationships can both be stated in
Newton's Gravity Law:
[tex]\rm F=G.\dfrac{m_1.m_2}{r^2}[/tex]
with F = gravitational force,
G = gravitational constant,
m1, m2 = mass of object,
r = distance between two objects.
The distance-r and mass of the box(m₁) are the same, then the largest object's mass (m₂)exerts a large gravitational force, because the gravitational force is directly proportional to the mass of the two objects
_____increases when a ball bounces up and decreases as ball does down. Answers choices. A.Thermal Energy. B. Kinetic Energy. C. Potential Energy. D. Heat
Answer:
C. potential energy
Explanation:
got 100 on edg
For calcium-42, How many protons,
neutrons and electrons are present,
respectively.
A. 20, 42, 20
B. 20, 22, 20
C. 20, 22, 18
D. 42, 20, 20
Answer:
B. 20, 22, 20
Explanation:
The atomic number (Z) of calcium is 20, that is, it has 20 protons.
The mass number (A) of calcium-42 is 42. The mass number is equal to the sum of protons and neutrons. Then,
p⁺ + n⁰ = 42
n⁰ = 42 - p⁺
n⁰ = 42 - 20
n⁰ = 22
Since calcium is electrically neutral, it has the same number of protons (+) and electrons (-). Then, calcium has 20 electrons.
Which event would most likely lead to a thunderstorm g i v i n g b r a i n l e s i t HELP
--
Answer:
A
Explanation:
hope it helps
Answer:
A
Explanation:
I got right
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Question 1
1 pts
Where did most of the heat of the Earth come from at its formation?
O Seismic waves
O Radioactive decay
O Planetesimals crashing into each other
Peridotite xenoliths
Question 2
1 pts
Answer:
radioactive decay
Explanation:
a study reveals that only about half of our planets internal heat stems from natural radioactivity the rest is primordial heat left over from when earth first coalesced from a hot ball of gas dust and other material
for tour substances.
Melting and Boiling
Points of Substances
Name
Melting Boiling
Point (°C) Point (°C)
-101
-35
-210
- 196
Chlorine
Nitrogen
Oxygen
Hydrogen
-218
183
-259
-253
Which substance is a solid at -200°C?
(Numerical problems) A car is running with the velocity of 72km/h. What will be it's velocity after 5s if it's acceleration is -2m/s square
The car's velocity after 5s : 10 m/s
Further explanationGiven
velocity=v=72 km/h=20 m/s
time=t = 5 s
acceleration=a = -2 m/s²
Required
velocity after 5s
Solution
Straight motion changes with constant acceleration
[tex]\tt v_f=v_i+at[/tex]
vf=final velocity
vi = initial velocity
Input the value :
[tex]\tt v_f=20+(-2).5\\\\v_f=20-10\\\\v_f=10~m/s[/tex]
The car is decelerating (acceleration is negative) so that its speed decreases
Answer:
The Velocity after 5s if its acceleration is -2m/s is 10 m / s.
Explanation:
The motion equation is given by v = u + a x t.
Initial speed (u) is equal to 72 km/h.
Acceleration (a) equals 2 m/s2.
Time (t) = 5s.
Changing the initial velocity's direction from km/h to m/s:
1 km/hr is equal to 1000 m/3600 s/5/18 m/s.
velocity (u) is equal to 72 x (5 / 18) m/s, or 20 m/s.
The motion equation can be used to calculate final velocity.
To change values in the equation of motion, do the following:
Final Velocity (v) = u + a x t
v = u + a x t
v = 20 m/s + (-2 x 5) m/s
v = (20 - 10)m/s v = 10 m/s
As a result, the car's speed after 5 seconds will be 10 m/s.
To know more about Velocity,
brainly.com/question/24567267
brainly.com/question/22038177
current divides between the available path?
What ratio of concentration of ammonia and ammonium chloride should be mixed to
prepare a buffer solution of pOH 5? (Kb for NH3 =1.8 x 10-4)
The ratio of concentration of ammonia and ammonium chloride : 0.05
Further explanationGiven
pOH=5
Kb for NH3 =1.8 x 10-4
Required
The ratio of concentration of ammonia (NH₃) and ammonium chloride(NH₄Cl)
Solution
Solutions containing ammonia and its salt: ammonium chloride are called alkaline buffers
Can be formulated : ( for the same of the volume, mol=concentration)
[tex]\tt \displaystyle [OH-]=Kb\times\frac{weak\:base\:mole}{salt\:mole\times valence}[/tex]
pOH=-log [OH⁻]
pOH=5⇒[OH⁻]=10⁻⁵
Valence for NH₄Cl = 1, so the concentration ratio :
[tex]\tt 10^{-5}=1.8\times 10^{-4}\times \dfrac{[~NH_3]}{[NH_4Cl]}\\\\0.05=\dfrac{[~NH_3]}{[NH_4Cl]}[/tex]
HELP ME DUE IN 5 MINUTES I WILL GIVE BRAINLIEST
Most people understand that resources need to be conserved. For example, when brushing your teeth, you conserve water by turning it off until you need it again. Energy within a system follows the Law of Conservation of Energy, so what does the Law of Conservation of Energy mean?
Group of answer choices
Energy can be transformed and destroyed.
Energy cannot be destroyed or created.
Energy cannot be transferred or used up.
Energy can be lost or made.
Answer:
Energy cannot be destroyed or created.
C. i know this is right
Explanation:
3Ba2+(aq) + 2PO43−(aq) ⇌ Ba3⎛⎝PO4⎞⎠2(s). Is Kc> 1, < 1, or ≈ 1?
Answer:
Kc < 1
Explanation:
Since the product formed is in solid state, from law of mass action.
Kc = 0
[Ba2+]³[PO4³-]²
hence Kc is 0
it was believed that earth was a stationary object at the center of the universe all other objects in space without to go around earth which of these is a criticism of this idea
Answer: is that a question or
Explanation:
Answer:
its c
Explanation:
How much heat is necessary to vaporize 685 g of H20 at 100°C? The heat of vaporization
of H2O is 540 cal/g.
0 370,000 cal
O 1.22 x 103 cal
O 88,400 cal
01.27 kcal
h
Question 8
3.33 pts
Answer:
370,000 cal
Explanation:
Step 1: Given data
Mass of water (m): 685 gHeat of vaporization of water (ΔH°vap): 540 cal/gStep 2: Calculate the heat necessary to vaporize 685 g of water
Vaporization is the process in which a liquid converts to a gas, at a constant temperature. The heat required (Q) is:
Q = ΔH°vap × m
Q = 540 cal/g × 685 g
Q = 3.70 × 10⁵ cal
Please help....thank you
Answer:
a. volcanic changes create new land
which 2 not one 2! hjmdnxhjund
Answer:
A and D then I guess
Explanation:
sorry hope this helps!
magnesium sulfide + nitric acid net ionic
Answer:
MgSO_3(s) + 2 HNO_3(aq) rightarrow Mg^2+(aq) + 2 NO_3^-(aq) + SO_2(g) + H_2O(l) b.
Explanation:
The balanced net ionic equation for the reaction of magnesium sulfite with nitric acid is a. MgSO_3(s) + 2 HNO_3(aq) rightarrow Mg^2+(aq) + 2 NO_3^-(aq) + SO_2(g) + H_2O(l) b.