Answer:
Freezing point: 32 ºF (0ºC)
Melting point: 32 ºF (0ºC)
Boiling point: 203°F (95°C)
Explanation:
At the boiling point, the vapor pressure of a liquid equals the external pressure. The normal melting point and boiling point of water at 1 atm are 0°C and 100°C, respectively. Decreasing the pressure under 1 atm (what happens when we are at high altitudes) will lower the boiling point since the external pressure will be lower, and it will become equal with the vapor pressure at a lower temperature.
However, the melting point and freezing point will stay unaffected since they don't depend on air-pressure; so at 0 or 5000 meters they will still be 0°C (remember that, since water is a pure substance, the freezing and melting points will be the same).
What is the half-life of polonium-210 if it takes 828 days for a sample to be reduced to 1.6% of its original mass?
Answer:
The half-life of polonium-210 is approximately 138.792 days.
Explanation:
We must remember that the decay of a radioisotope is modelled by this ordinary differential equation:
[tex]\frac{dm}{dt} = -\frac{m(t)}{\tau}[/tex]
Where:
[tex]m(t)[/tex] - Current mass of the isotope, measured in grams.
[tex]\tau[/tex] - Time constant, measured in days.
Whose solution is:
[tex]m(t) = m_{o}\cdot e^{-\frac{t}{\tau} }[/tex]
Where [tex]m_{o}[/tex] is the initial mass of the isotope, measured in grams.
Our first step is to determine the value of the time constant:
[tex]-\frac{t}{\tau} = \ln \frac{m(t)}{m_{o}}[/tex]
[tex]\tau = -\frac{t}{\ln \frac{m(t)}{m_{o}} }[/tex]
If we know that [tex]\frac{m(t)}{m_{o}} = 0.016[/tex] and [tex]t = 828\,days[/tex], then the time constant of the radioisotope is:
[tex]\tau = -\frac{828\,days}{\ln 0.016}[/tex]
[tex]\tau \approx 200.234\,days[/tex]
And lastly we find the half-life of polonium-210 ([tex]t_{1/2}[/tex]), measured in days, by using this expression:
[tex]t_{1/2} = \tau \cdot \ln 2[/tex]
[tex]t_{1/2} = (200.234\,days)\cdot \ln 2[/tex]
[tex]t_{1/2}\approx 138.792\,days[/tex]
The half-life of polonium-210 is approximately 138.792 days.
Which of the following elements is among the alkali metals?
Answer:
Alkali metals are: Lithium(Li), Sodium(Na), Potassium(K), Rubidium(Rb), Cesium(Cs) and Francium(Fr).
Explanation:
I cant understand your question mate, but these are all the alkali metals, because they are in the first group. Note that Hydrogen(H) is not an alkali metal. Hope that helps. God bless you.
The alkali metals are lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr).
What is the periodic table?The periodic table has been the arrangement of the elements based on the reactivity and the electrons in the valence shell.
The left side of the periodic table has been consisted of the metals, while moving from left to right the metallic character decreases and the nonmetallic character increase.
The group 1 of the periodic table has been consisted of the metals with 1 valence electrons. The group has been termed as alkali metals, as the reaction of the elements of this group with water forms alkali.
The elements belonging to group 1 of the periodic table are lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr).
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Carbohydrates are made up of carbon, hydrogen, and __________.
Which term best completes the sentence?
oxygen
copper
helium
potassium
Answer:
oxygen
Explanation:
This is for my Science assignment: A molecule is made up of at least (blank) different atoms. Fill in the blank, please. Best answer gets Brainliest!
Answer:
2 differet atoms.
Explanation:
Molecule: group of two or more atoms held together by chemical bonds. So, minimum 2 atoms are required to form a molecule.
which element is less electronegative than silicon (Si)
Answer:
caesium
Explanation:
because it's lesssssssss
What is 0.75140000 in scientific notation?
Answer:
i need help too
Explanation:
helppp
Determine the overall charge on particles with the subatomic makeups given.
13 protons, 14 neutrons, and 10 electrons
+3
Answer:
The correct solution will be "+3".
Explanation:
The given values are:
Number of protons
= 13
Number of neutrons
= 14
Number of electrons
= 10
As we know,
⇒ [tex]Charge = Number \ of \ protons - Number \ of \ electrons[/tex]
On putting the estimated values, we get
⇒ [tex]=13 - 10[/tex]
⇒ [tex]=+3[/tex]
The overall charge on the particle would be +3
Atomic ChargeThe atomic charge on a particle is determined by the number of protons (positive charge) and electrons (negative charge) in the atoms of the particle.
Neutral atoms have equal number of protons and neutronsNegatively charged atoms have more electrons than protonsPositively charged atoms have more protons than electronsThus, an atom with 13 protons and 10 electrons will have a residual proton of 3, making the overall charge to be +3.
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what have you learned about the four subsystem?
An air conditioning unit turns off once it reaches its goal temperature. The house warms up and the air conditioning unit turns on again.
When the air conditioning unit turns on, it is an example of:
A) input
B) process
C) output
D) feedback
Answer:
D) feedback.
Explanation:
An air condtioning unit consists of the following elements according to available choices:
Inputs: Refrigerant, air from surroundings, electricity.
Process: Refrigeration cycle.
Output: Conditioned air at goal temperature.
Feedback: Activation and deactivation of the air conditioning unit depending on indoor temperature.
When the air conditioning turns on and off to keep goal temperature indoors, a control stage consisting in a controller and a action element is acting to reverse the behavior of the process with a view to keep goal temperature.
Hence, correct answer is D.
What is 0.75140000 in scientific notation
Answer:
Sig Figs
8
Decimals
8
Scientific Notation
7.5140000 × 10-1
Explanation:
What is the difference between dehydration and hydrolysis?
Answer:
Some differences between the given particular topics are described below.
Explanation:
Hydrolysis occurs as the water is absorbed in some kind of a response to breaking up the polymer through its corresponding monomers while Dehydration synthesis happens whenever water has been formed as a formation of the polymerization of the latter's corresponding monomers.Hydrolysis seems to be a method during which a chemical bond becomes dissolved by a water molecule while Dehydration would be a state of consuming less liquid than that of the natural rate.Match the words to the appropriate blanks in the sentences.
a. For the pair of compounds CO2 or NO2 the one with the highest boiling point is __________ .
b. For the pair of compounds NH3 or CH4 the one with the highest boiling point is _________
c. For the pair of compounds CS2 or CO2 the one with the highest boiling point is _________
1. CH4
2. NH3
3. CS2
4. NO2
5. CO2
Answer:
a. NO2
b. NH3
c. CO2
Explanation:
a. For the pair of compounds CO2 or NO2 the one with the highest boiling point is __________ .
The answer is NO2. It has a higher boiling point than CO2 because it exhibits dipole-dipole interactions.
b. For the pair of compounds NH3 or CH4 the one with the highest boiling point is _________
NH3 has a higher boiling point compared to CH4. This is due to the presence of the hydrogen bonds in NH3,
c. For the pair of compounds CS2 or CO2 the one with the highest boiling point is _________
CS2 has a higher boiling point than CO2. This is because of the high molecular mass of CS2.
What did Aristotle believe?
At room temperature 20 Celsius and object had a mass of 25g and displaces 15 mL water in a cylinder. what is it’s density? If the object was cooled to point where it had only half of its original thermal energy. What would be it’s temperature in Kelvin and Celsius?
Answer:
Density = 1.67 g/cm³
New Temperature = 10°C ⇔ 283K
Explanation:
a. Density of a substance can be described as the mass (in grams) of a substance per litre (in mL or cm³) of liquid displaced.
Hence: Density = mass ÷ volume
Density = 25 ÷ 15
Density = 1.67 g/cm³
b. If the object is cooled to half of its original temperature, the new temperature is assumed to be half of the room temperature
Hence, the substance's new temperature will be = 20÷2
=10°C ⇔ 283K (i.e 10 + 273)
Dogs can be acutely poisoned if they eat very small amounts of , a sweetener commonly found in sugar-free gum.
Answer:
Xylitol
Please give me the brainliest if you found this helpful
Number of electrons absorbed by the main energy level (n = 4):
a)8
b)18
c)32
d)56
Answer:
C
Explanation:
Because 2 x n square gives the total energy level been absorbed = 2 x16
=32
Glass, rubber, and plastic are all forms of A. allotropic solids C. covalent network solid B. amorphous solids X D. crystalline solids Elements, such as sulfur, carbon, and phosphorus, are more than one structural form in the solid state. A. allotropic C. crystalline B. amorphous D. orthorhombic RECI CORRECT CHECK
Answer:
B. amorphous
Explanation:
Examples of amorphous solids include glass, rubber, and plastics.
In what two ways can an object possess energy?
Explanation:
An object can possess energy in tow ways by it's motion or position
If you burn 57.9 g of hydrogen and produce 517 g of water, how much oxygen reacted?
In order to make water (H2O) out of hydrogen (H2), you also need OXYGEN (O2) gas. So, first write a correctly balanced equation for this reaction.
2H2(g) + O2(g) ==> 2H2O
Now, convert 59.5 g of H2 to moles, then figure out moles of H2O and then moles of O2 used to do this.
moles H2 = 59.5 g H2 x 1 mole/2 g = 29.8 moles H2
moles H2O formed = 531 g H2O x 1 mole/18 g = 29.5 moles H2O
So, the mole ratio of H2 to H2O is 1:1 meaning that the moles of O2 used will be 1/2 that amount. This is the case because from the balanced equation you see that 1 O2 reacts with 2 H2 and produces 2 H2O.
Amount of O2 used = 29.8/2 = 14.9 moles
Amoeba eat by using. What method
Answer:
Amoebas use their pseudopods to ingest food by a method called phagocytosis (Greek: phagein, to eat). The streaming of protoplasm inside the pseudopods moves the amoeba forward.
Explanation:
In order for convection to transfer heat, particles need to
absorb solar and fossil energy
O circulate and move within a liquid or gas
O make contact with the heat source
transmit electromagnetic waves
Answer:
The answer is B "circulate and move within a liquid or gas"
Calculate the lattice energy for LiF(s) given the following: sublimation energy for Li(s) +166 kJ/mol bond dissociation energy to produce F(g) +77 kJ/mol first ionization energy (IE1) of Li(g) +520. kJ/mol electron affinity (EA) of F(g) -328 kJ/mol enthalpy of formation of LiF(s) -612 kJ/mol
Answer:
The lattice energy for LiF(s) is -1047 kJ/mol
Explanation:
Given;
Sublimation energy, ΔHs = 166 kJ/mol
bond dissociation energy, BE = +77 kJ/mol
first ionization energy, IE₁ = +520 kJ/mol
electron affinity, EA = -328 kJ/mol
enthalpy of formation, ΔHf = -612 kJ/mol
[tex]L_iF_{(s)}[/tex] ⇄ [tex]Li_{(g)}^+\ \ + \ \ F^-_{(g)}[/tex]
Apply the following equation to calculate the lattice energy for, LiF(s),
Let the lattice energy = U
ΔHf = ΔHs + BE + IE₁ + EA + U
-612 = 166 + 77 + 520 -328 + U
-612 = 435 + U
U = -612 - 435
U = -1047 kJ/mol
Therefore, the lattice energy for LiF(s) is -1047 kJ/mol
The lattice energy of LiF is -1047 KJ/mol.
The lattice energy is the energy is the energy evolved when one mole of the ionic solid is formed from its constituents. The ionic lattice energy depends on the size of the ions.
We have the following information from the question;
Enthalpy of formation of LiF (ΔHf ) = -612 kJ/mol
Heat of sublimation of Li (ΔHs) = +166 kJ/mol
Bond energy of F2 (BE) = +77 kJ/mol
Ionization energy of Li (IE₁) = +520. kJ/mol
Electron affinity of F(g) (EA) = -328 kJ/mol
Lattice energy (U) = ?
The lattice energy can be obtained using the Hess law of constant heat summation as follows;
ΔHf = ΔHs + BE + IE₁ + EA + U
U = ΔHf - [ΔHs + BE + IE₁ + EA ]
U = -612 kJ/mol - [(+166 kJ/mol ) + ( +77 kJ/mol) + (+520. kJ/mol) + ( -328 kJ/mol)]
U =-612 kJ/mol - 435 KJ/mol
U = -1047 KJ/mol
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A flask with a volume of 125.0 mL contains air with a density of 1.122 g/L. What is the mass of the air contained in the flask?
Answer:
The answer is
0.14 gExplanation:
To find the mass of a substance given the density and volume we use the formula
mass = Density × volumeFrom the question
Density = 1.122 g/L
volume = 125 mL
We must convert the volume from mL to L
1000 mL = 1 L
125 mL = 0.125 L
volume = 0.125 L
Substitute the values into the above formula and solve for the mass
That's
mass = 1.122 × 0.125 = 0.14025
We have the final answer as
0.14 gHope this helps you
Determine the number of significant figures in the following measurement:
16.08 Liters
Answer:
Four significant figures.
Explanation:
Hello,
In this case, considering that the measurement 16.08 L has four digits we must take into account that all are significant even the zero due to fact that is to the right of the first nonzero digit which is 1, therefore, the measurement has four significant figures.
Best regards.
Which of the following correctly describes what happens to the kinetic energy of water when it changes from steam to a liquid? The kinetic energy of the molecules increases. The kinetic energy of the molecules decreases. The kinetic energy of the molecules increases then decreases. There is no change in the kinetic energy of the molecules
The element uranium ( U ) has three naturally occuring isotopes, U234 , U235 , and U238 . U234 has an isotopic mass of 234.04 u and a relative abundance of 0.0054%. U235 has an isotopic mass of 235.04 u and a relative abundance of 0.7204%. U238 has an isotopic mass of 238.051 u and a relative abundance of 99.2742%. Calculate the average atomic mass of uranium.
Answer:
[tex]m_U=238.03u[/tex]
Explanation:
Hello,
In this case, since the average atomic mass for the given element is computed by taking into account the mass of each isotope and their abundance, we proceed as follows:
[tex]m_U=234.04u*0.0054\%+235.04u*0.7204\%+238.051u*99.2742\%\\\\m_U=0.01264+1.69323+236.3232\\\\m_U=238.03u[/tex]
Best regards.
What is the closest to potassium
You wish to prepare 250.0250.0 mL of a 400.0400.0 ppm w/v Fe2+Fe2+ ( MW=55.845 g/molMW=55.845 g/mol ) solution. How many grams of ferrous ammonium sulfate hexahydrate (Fe(NH4)2(SO4)2⋅6H2O(Fe(NH4)2(SO4)2⋅6H2O , MW=392.14 g/molMW=392.14 g/mol ) are needed to prepare this solution? Assume the final solution has a density of 1.00 g/mL.
Answer:
You need 0.702g of ferrous ammonium sulfate hexahydrate to prepare the desired solution.
Explanation:
First, you want to prepare 250.0mL of a 400.0ppm of Fe²⁺ (That is mg/L, w/v):
0.250L * (400mg / L) = 100mg Fe²⁺ = 0.1g Fe²⁺
Molar mass of Fe is 55.845g. moles are:
0.1g Fe²⁺ * (1mol / 55.845g) =
1.79x10⁻³ moles Fe²⁺The Fe²⁺ comes from ferrous ammonium sulfate hexahydrate, as 1 mole of this salt contains 1 mole of Fe²⁺, moles of the salt you need are:
1.79x10⁻³ moles Fe(NH₄)₂(SO₄)₂.6H₂O.
To convert these moles to grams you must use molar weight, MW, thus:
1.79x10⁻³ moles Fe(NH₄)₂(SO₄)₂.6H₂O * (392.14g / 1mol) =
You need 0.702g of ferrous ammonium sulfate hexahydrate to prepare the desired solution.is oxygen an exhaustible natural resource ?
Answer: False
Explanation:
resources which are present in unlimited quantity in nature are called as inexhaustible natural resources.
For each of the described sets of data, choose the graph that best displays the data.
Changes in the temperature of an ice cube taken every minute for 15 minutes
a.) line graph
b.) scatter plot
c.) bar graph
d.) histogram
The changes in the temperature of an ice cube taken every minute for 15 minutes can be easily evidenced by a line graph (Option A).
What is a line graph?A line graph is a diagram that represents the changes in one variable through a horizontal axis and one vertical axis.
A line graph is very useful to show how a variable may change along a given period of time.
In conclusion, the changes in the temperature can be evidenced by a line graph (Option A).
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Answer:
A) line graph
Explanation:
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