Answer:
What are the pages on? Like what topic?
Explanation:
Sodium-25 was to be used in an experiment, but it took 3.0 minutes to get the sodium from the reactor to the laboratory. If 8.0 mg of sodium-25 was removed from the reactor, how many mg of sodium-25 were placed in the reaction vessel 3.0 minutes later if the half life of sodium-25 is 60 seconds.
Sodium-25 after 3 minutes : 1.0625 mg
Further explanationGeneral formulas used in decay:
[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}[/tex]
T = duration of decay
t 1/2 = half-life
N₀ = the number of initial radioactive atoms
Nt = the number of radioactive atoms left after decaying during T time
No=8 mg
t1/2=60 s
T=3 min=180 s
[tex]\tt Nt=No\dfrac{1}{2}^{T/t1/2}\\\\Nt=8.5\dfrac{1}{2}^{180/60}\\\\Nt=8.5(\dfrac{1}{2})^3\\\\Nt=1.0625~mg[/tex]
Describe the source of angle strain and torsional strain present in cyclopropane
Explanation:
The angle strain arises from the compression of the ideal tetrahedral bond angle of 109.5° to 60°. The large torsional strain occurs since all CH bonds on adjacent carbons are eclipsed.
The lateral angle that decrease in the lateral angle from 109.5 to 60 degree so, these is the main source of angle strain and torsional strain present in cyclopropane.
What is angle and torsional strain?Angle strain is the term for strain that results from departure from one or more ideal bond angles. Torsional strain is a chemical compound's resistance to bond twisting. Torsional strain between the bonds occurs when atoms separated by three bonds are arranged in an unstable staggered conformation rather than an eclipsed shape.
It exists in cyclopropane because its C-C-C bond angles must not exceed 60 degrees, which is less than the optimum bond angle of 109.5 degrees for tetrahedral carbon. It is the cause of these.
We are aware that three carbon atoms in a triangle plane break the cycle and cause each carbon to be sp3 hybridized. All carbon endeavors are sp3 hybridized, and we are aware that the sp3 hybrid angle is 109 degrees, 28 minutes at 109.5 degrees. But the single angle in cyclo-propane is only 60 degrees.
Personal strain results from the bending of bonds necessary to form a new molecule. The primary source of the angle strain and torsional strain found in cyclopropane is the decrease in lateral angle from 109.5 to 60 degrees.
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help me please! asap please
Answer:
1. A2. C3. BExplanation:
i hope it helps ;)
Hey yalll ok so like I need help & this is science or chemistry or whatever yall would like to call it! Can yall help me? I am having problems with this and I dont understand this so if yall could help me that would be Wonderfulllll! <3
Answer:
ill help but i cant see the problem
Explanation:
A hydrogen filled balloon has a bolume of 8.3 L at 36 C and 751 torr. How many moles of hydrogen are inside the balloon?
Answer:
0.33 mol
Explanation:
Given data:
Volume of balloon = 8.3 L
Temperature = 36°C
Pressure = 751 torr
Number of moles of hydrogen = ?
Solution:
Temperature = 36°C (27 +273 = 300 K)
Pressure = 751 torr (751/760= 0.988 atm)
Formula:
The given problem will be solve by using general gas equation,
PV = nRT
P= Pressure
V = volume
n = number of moles
R = general gas constant = 0.0821 atm.L/ mol.K
T = temperature in kelvin
PV = nRT
0.988 atm × 8.3 L = n × 0.0821 atm.L/ mol.K × 300 K
8.2 atm.L = n × 24.63 atm.L/ mol
n = 8.2 atm.L / 24.63 atm.L/ mol
n = 0.33 mol
how does a squirrel get prepare for the winter months?
Answer:
Well, I have pet squirrels, and I know they get acorns and other food, and dig up certain spots on the ground, then put their food in there. And they have food for the winter.
A food item that is left out of the refrigerator turns brown and forms bubbles and gas. What are the signs that this is a chemical reaction?
Check all that apply.
Heat is produced.
Heat is absorbed.
Bubbles appear.
A precipitate forms.
The color changes.
Answer:
C & E
Explanation:
During the reaction: Mg(s) + CuSO4(aq)
es)
MgSO4(aq) + Cu(s), what changes occur to magnesium?
A)Its oxidation number changes from +2 to 0 and it is reduced.
B)Its oxidation number changes from 0 to +4 and it is reduced.
C)Its oxidation number changes from 0 to +2 and it is oxidized.
D)Its oxidation number changes from +2 to +4 and it is oxidized.
Answer:
C
Explanation:
I did it on usatestprep
What did J.J. Thomson discover about electrons?
a
Atoms are indivisible.
b
Electrons are inside the nucleus of an atom.
c
Electrons are scattered in a positively charged atom.
d
Atoms of the same element have the same properties.
The answer is D
Brainliest?
need help please , thx
Answer:
vxxbvfdb
Explanation:
Answer:
sorry dude
Explanation:
i got no clue
Which of the following elements would you expect to lose one electron? Select all that apply.
a. sodium
b. chlorine
c. Fluorine
d. Potassium
Answer:
Potassium, sulfur, fluorine, barium
The elements that will lose one electron are:
a. sodium
d. Potassium
What will happen when an element looses one electron?An element in its natural state has an equal number of protons and electrons, giving it a net charge of zero; however, when an element loses an electron as part of a chemical reaction it becomes positively charged, or oxidized.
Out of the given options, sodium and potassium looses one electron and attains a positive charge leading to the formation of cation. While Fluorine and chlorine gains one electron and attains a negative charge leading to the formation of anion.
Thus, correct options are a and d.
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Which of the following is an example of erosion?
water freezing inside the cracks of rocks
stalactite and stalagmite formation in caves
plant roots pressing against the sides of rocks
glaciers moving rocks and soil through a valley
Answer:
Glaciers moving rocks and soil through a valley
Explanation:
The definition of Erosion is "the process of eroding or being eroded by wind, water, or other natural agents". Which in turn means the movement of glaciers is causing erosion on the local valley.
the last one
Explanation:
Are bonds broken or formed, throughout each phase change present on a heating
curve?
a 500 kilogram sample of substance decays to 125 kilograms over a period of 21.53 years. what is the half life of the sample substance
Answer:
Half life = 10.765 year
Explanation:
Given data:
Mass of sample = 500 Kg
Mass left after 21.53 years = 125 kg
Half life of substance = ?
Solution:
At tome zero = 500 kg
At 1st half life = 500 kg/2 = 250 kg
At 2nd half life = 250 kg/2 = 125 g
Half life:
Half life = time elapsed / number of half life
Half life = 21.53 year/2
Half life = 10.765 year
Question 24 (3 points)
Choose the element below that has correct information about the number of energy
levels/orbitals: (Use a period table to answer this question).
Lithium (Li) has one energy level
Sodium (Na) has three energy levels
Potassium (K) has three energy levels
Fluorine (F) has seven energy levels.
Answer:
sodium
Explanation:
Match the terms with their definitions
Frequency, Amplitude, Crest, Wavelength, Medium, Trough
Matter distributed by energy
Highest point of transverse wave
Lowest point of transverse wave
Distance between midpoint of wave and crest
Distance traveled in one wave cycle
Number of waves that pass per second
(from brainpop waves.) PLease HeLP (Worth 25 POINTS)
Answer:
amplitude= distance between midpoint of a wave and crest
crest= highest point of transverse wave
wavelength= distance traveled in one wave cycle
medium= matter distributed by energy
trough=lowest point of transverse wave
frequency=number of waves that pass per second
Explanation:
A wave is a dynamic perturbation of one or even more quantities that propagates in a specific medium.
What is wave?A wave is a dynamic perturbation of one or even more quantities that propagates in physics, mathematics, or related sciences. When waves oscillate frequently around an equilibrium position at a certain frequency, they are said to be periodic. A traveling wave is one in which the whole waveform moves inside one direction; in contrast, a standing wave is one in which two periodic waves are overlaid and move in the opposing directions.
In a wave form, there are some points in which the wave amplitude seems reduced or even zero, and these positions have null vibration amplitudes. A wave equation or perhaps a one-way wave equation describing single wave propagation inside a specific direction is frequently used to describe waves.
amplitude= distance between midpoint of a wave and crest
crest= highest point of transverse wave
wavelength= distance traveled in one wave cycle
medium= matter distributed by energy
trough=lowest point of transverse wave
frequency=number of waves that pass per second
Therefore, a wave is a dynamic perturbation of one or even more quantities that propagates
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Which virus lastes the longest in the whole history? ( Sorry, I don't have options)
Answer:
COLD AND FLU!!!!
Explanation:
Answer:
CORONAVIRUS UGH
Explanation:
Sugar(C6H1206) and salt( NaCl) are examples of
Answer:
compounds
Explanation:
It is a substance formed when two or more. When the elements are joined, the atoms lose their individual properties and have different properties from the elements they are composed of.
Answer:
Brain big big brain
Explanation:
Biggest brain small brain Big brain big stonks
What is the number of neutrons in Hydrogen, O (A= 1, Z= 1)?
Answer:
Explanation:
Hydrogen has 1 proton and one nuetron
Oxygen has 8 protons nad 8 neutrons
Which of the following is a valid unit for specific heat?
Explanation:
The specific heat capacity is the amount of heat required to raise the temperature of 1mole or 1kg or 1g of substance by 1k or 1°C
This property is an intensive property of matter and does not depend on the quantity of matter present.
Some of the unit of specific heat are;
J/g°C, J/kg°C, J/mol°C, J/molK , Cal/g°C
Question 23 (1 point)
A student is given an object with a mass of 14.8 grams. When placed into a
graduated cylinder the water level rises from 25.0 mL to 34.7 mL.
What is the density of the object and would you expect it to float or sink in the
graduated cylinder if water has a density of 1.00 g/mL? Show all of your work.
Answer:
d = 1.53 g/mL
Object will sink into water
Explanation:
Given data:
Mass of object = 14.8 g
Initial volume of water = 25.0 mL
Final volume after adding object = 34.7 mL
Density of object = ?
Density of water = 1.00 g/mL
Solution:
Volume of object = Total volume - volume of water
Volume of object = 34.7 mL - 25.0 mL
Volume of object = 9.7 mL
Density of object;
d = mass/volume
d = 14.8 g / 9.7 mL
d = 1.53 g/mL
The density of water is 1.00 g/mL which means object is heavier than water thus object will sink into the water. The object with density less than water are float in it.
Which statement about the relationship between laws, hypotheses, and theories is true?
Are bonds broken or formed, throughout each phase change present on a heating
curve?
Answer:
During a phase change no chemical bonds are broken. Atoms are not rearranged because a phase change is a physical change rather then a chemical change. However, intermolecular forces are almost entirely removed from the liquid since the intermolecular forces are what cause the liquid to be a liquid.
Explanation:the nature of the intermolecular forces (IMF) will not change when the state changes from solid to liquid, however, the number of IMF changes.
Which of the following practices can help control erosion?
recycling paper
harvesting earlier
tree removal
contour plowing
Answer:
Contour plowing
Explanation:
Contour plowing is one of the activity that can help control the rate of erosion in a given place.
Erosion is the washing away of the layer of the earth. In agricultural practices, rich top soil can be eroded if adequate measures are not taken. Contour plowing is the process of planting along the sides of a ridge following the contour patterns. This helps to break down slopes and reduce erosion.The density of magnesium is 1.7/cm3, and the density of iron is 7.9g/cm3. Consider a block of iron with a mass of 819 g. What is the mass of a block of magnesium that has the same volume as the block of iron?
all matter has physical and chemical properties. These properties can be used to identify the type of matter. Which of these statements describe a physical property?
Explanation:
Physical properties of matte tells us everything about a substance when no change is occurring to its constituents.
Such properties are best observed with our senses. Also, physical properties can be observed using equipment in the laboratory or some apparatus.
Examples of these properties are state of matter, color, odor, taste, texture, hardness, solubility in water, melting point, boiling point, density, viscosity and spectroscopic patterns.According to Boyle’s law, when the pressure of a gas increases at constant temperature, its volume
Answer:
the volume increases
Explanation:
Determine if any of the following reactions could be written as net ionic equations. Write yes or no in the blanks.
_____a. CH4 (g) + 2 O2 (g) = CO2 (g) + 2 H2 O(g)
_____b. Cu(s) + 2 AgNO3 (aq) = 2 Ag(s) + Cu(NO3 )2 (aq)
_____c. MgCl2 (aq) + 2 KOH(aq) = Mg(OH)2 (s) + 2 KCl(aq)
_____d. CaCO3 (s) + 2 HCl(aq) = CaCl2 (aq) + CO2 (g) + H2 O(l)
Reaction b,c and d could be written as net ionic equations.
Further explanationThe electrolyte in the solution produces ions.
The equation of a chemical reaction can be expressed in the equation of the ions
For strong electrolytes (the ionization rate = 1) is written in the form of separate ions, while the weak electrolyte (degree of ionization <1) is still written as an un-ionized molecule
In the ion equation, there is a spectator ions that is the ion which does not react because it is present before and after the reaction
When these ions are removed, the ionic equation is called the net ionic equation
For gases and solids including water (H₂O(l)) can be written as an ionized molecule
So only the dissolved compound is ionized ((expressed in symbol aq)
To see the reaction can be expressed in terms of the net ionic equation, we must see that there are two or more ions that are the same from both sides of the reactant and the product in the form of aquoeus (because the form of compounds in the form of gases, solids and liquids will remain molecular and non-ionized)
CH4 (g) + 2 O2 (g) = CO2 (g) + 2 H2 O(g)
No⇒no compounds in the aqueous form
Cu(s) + 2 AgNO3 (aq) = 2 Ag(s) + Cu(NO3 )2 (aq)
Cu(s) + 2 Ag⁺+ 2NO3⁻ (aq) = 2 Ag(s) + Cu²⁺ +2NO3⁻ (aq)
Cu(s) + 2 Ag⁺(aq) = 2 Ag(s) + Cu²⁺(aq)
yes, because there are NO3 (spectators ion) on both sides
MgCl2 (aq) + 2 KOH(aq) = Mg(OH)2 (s) + 2 KCl(aq)
Mg²⁺(aq)+2Cl⁻ (aq) + 2K⁺(aq)+2OH⁻(aq) = Mg(OH)2 (s)+ 2K⁺(aq)+2Cl⁻(aq)
Mg²⁺(aq)+2OH⁻(aq) = Mg(OH)2 (s)
yes, because there are 2Cl⁻ (aq) and 2K⁺(aq (spectators ion) on both sides
CaCO3 (s) + 2 HCl(aq) = CaCl2 (aq) + CO2 (g) + H2 O(l)
CaCO3 (s) + 2 H⁺(aq)+2Cl⁻(aq) = Ca²⁺(aq)+2Cl⁻ (aq) + CO2 (g) + H2 O(l)
CaCO3 (s) + 2 H⁺(aq) = Ca²⁺(aq) + CO2 (g) + H2 O(l)
yes, because there are Cl⁻ (spectators ion) on both sides
Comprehensive studies have shown that forensic scientists should look for between 8 to 16 points to establish identification
based on fingerprints.
true or false
Answer:
FALSE
Explanation:
right answer on plato:)
Compare and contrast how observations and results can be used to
support a conclusion to an experiment.
Answer:
by statistical analyses, especially by determining the p-value
Explanation:
In general, observations and results obtained from experimental procedures are subjected to a statistical test to check the robustness of the working hypothesis. The p-value is the most widely used statistical index in order to test such observations and results. The p-value is the statistical probability of obtaining extreme observed results when the null hypothesis is considered correct. A p-value lesser than 0.05 generally is considered statistically significant and then the null hypothesis can be rejected. In consequence, a very low p-value (which is obtained by statistical analysis of the observations and results), indicates that there is strong evidence in support of the alternative hypothesis.