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
Symbol #e" Orbital diagram and electron configuration can someone help
N - 7 - 1s2 2s2 2p3
O - 16 - 1s2 2s2 2p6 3s2 3p4
Mn - 25 - 1s2 2s2 2p6 3s2 3p6 4s2 3d5
Ga - 31 - 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p1
Which activity is an example of chemical change?
The greater the resistance, the less current there is for a given voltage.
Please select the best answer from the choices provided
True
False
❤️❤️❤️
Answer:
The answer is True.
what is the kinetic energy of a 3kg ball that is rolling at 2 meters per second
Answer:
6 JExplanation:
The kinetic energy of an object can be found by using the formula
[tex]k = \frac{1}{2} m {v}^{2} \\ [/tex]
m is the mass
v is the velocity
From the question we have
[tex]k = \frac{1}{2} \times 3 \times {2}^{2} \\ = \frac{1}{2} \times 3 \times 4 \\ = 3 \times 2[/tex]
We have the final answer as
6 JHope this helps you
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.
Please help....thank you
Answer:
a. volcanic changes create new land
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.
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.
What is the concentration of a solution made by diluting 35 mL of 6.0 M HCl to a final volume of 750 mL?
If 2.49g of CuNO3 is dissolved in water to make O.830M solution, what is the volume of the solution in milliliters?
How many moles of NaOH are present in 13.5mL of 0.17 M NaOH?
Answer:
1. 0.28M
2. 24mL
3. 0.002295moles of NaOH.
Explanation:
1. The 6.0M HCl solution is diluted from 35mL to 750mL, that is:
750mL / 35mL = 21.43 times
The 6.0M HCl solution is diluted 21.43 times, the final concentration is:
6.0M / 21.43 = 0.28M
2. First, we need to convert grams of CuNO3 to moles and then, as molarity is moles per liter we can solve for volume of solution in liters and convert it to mililiters:
Moles CuNO3 -Molar mass 124.9g/mol:
2.49g * (1mol / 124.9g) = 0.020 moles of CuNO3
Volume is:
0.020 moles * (1L / 0.830mol) = 0.0240L * (1000mL / 1L) = 24mL
3. In 13.5mL = 0.0135L of 0.17M NaOH the moles are:
0.0135L * (0.17mol / L) = 0.002295moles of NaOH
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
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]
How many moles are in 11.0 grams of methane (CH4)?
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]
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
why can three atoms of magnesium have different masses?
Answer:
Three atoms of magnesium can have different masses because each of the three atoms has a different number of neurons.
I hope this helped :)
The differences in masses of the three magnesium atom is due to there differences in there neutron number
Isotopes are members of an element that all have the same number of protons but different numbers of neutrons.
These are 2 or mores type of atoms that have the same atomic number but different nucleon numbers due to the different number of neutron in the nuclei.
The reason why three atoms of magnesium has different masses is due to Isotropy.
The differences in masses of the three magnesium atom is due to there differences in there neutron number.
The differences in masses is caused by the differences of their neutron number.
learn more about isotopy here: https://brainly.com/question/25305592?referrer=searchResults
Please help Fast i dont Know
Please help will give brainliest
Answer:
the answer id D
Explanation:
i dont know im just living here 5
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.
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]
(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
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
current divides between the available path?
What mass of calcium chloride is required to prepare 3.20 L of 0.850 M of calcium chloride solution?
Answer:
301.92 g of CaCl2.
Explanation:
The following data were obtained from the question:
Volume of CaCl2 solution = 3.20 L
Molarity of CaCl2 solution = 0.850 M
Mass of CaCl2 =?
Next, we shall determine the number of mole of CaCl2 in the solution. This can be obtained as illustrated below:
Volume of CaCl2 solution = 3.20 L
Molarity of CaCl2 solution = 0.850 M
Mole of CaCl2 =?
Molarity = mole /Volume
0.850 = mole of CaCl2 /3.20
Cross multiply
Mole of CaCl2 = 0.850 × 3.20
Mole of CaCl2 = 2.72 moles
Finally, we shall determine the mass of the CaCl2 needed to prepare the solution as follow:
Mole of CaCl2 = 2.72 moles
Molar mass of CaCl2 = 40 + (2×35.5)
=40 + 71
= 111 g/mol
Mass of CaCl2 =?
Mole = mass /Molar mass
2.72 = mass of CaCl2 /111
Cross multiply
Mass of CaCl2 = 2.72 × 111
Mass of CaCl2 = 301.92 g
Therefore, 301.92 g of CaCl2 is needed to prepare the solution.
Why is light a wave?
Answer:
an electromagnetic wave
Explanation:
A typical home instant pot has an internal volume of 6.5 Liters. If the steam inside an instant pot with an internal pressure of 191.0 kPa and a temperature of 750.0 K was released into the atmosphere at 101.3 kPa and 298K, what volume with the steam occupy in the atmosphere?
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?
Describe the reaction of zinc with sulphuric acid
Answer:
Zinc reacts with dilute sulphuric acid to produce hydrogen gas (H2) and zinc sulphate. This is an example of displacement reaction of a non-metal by a metal. ... ZnSO4 is different in chemical composition and chemical properties than Zn and H2SO4 so it is a chemical change.
Answer:
Reaction of Zinc with Dilute Sulphuric Acid
Zinc is more reactive than hydrogen and it displaces hydrogen from dilute acids. Zinc reacts with dilute sulphuric acid to form zinc sulphate and hydrogen gas is evolved. This is a single displacement reaction of a non-metal by a metal. ... So, this reaction is a chemical change.
What is the mass, in grams, of 50.0L of N2 at STP?
Hey there!:
Molar mass N₂ = 28.0134 g/mol
28.0134 g ------------------- 22.4 L (at STP )
mass N₂ -------------------- 50.0 L
mass N₂ = 50.0 x 28.0134 / 22.4
mass N₂ = 1400.67 / 22.4
mass N₂ = 62.529 g
Hope this helps!
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