Answer:
Pure Substance. A sample of matter, either a single element or a single compound, that has definite chemical and physical properties. Element. A pure substance that cannot be broken down into other substances by chemical or physical means.
Explanation:
Sorry if it's wrong!!!!!!!
Answer:
Elements
Explanation:
Elements cannot be broken down into anything simpler physically or chemically. Compounds: are pure substances that are made up of more than l type of atom and can be broken down or decomposed into its individual elements by chemical methods, but cannot be separated by physical methods.
Which element has the electron configuration,
1s2 2s2 2p6 3s2 3p3 4s2 3d10 4p6 5s2 4d5 ?
a
manganese
b
technetium
c
rhenium
d
europium
Answer:
B. technetium
Explanation:
6.An acid-base indicator is usually a weak acid with a characteristic color in the protonated and deprotonated forms. Because bromocresol green is an acid, it is convenient to represent its rather complex formula as HBCG. HBCG ionizes in water according to the following equation:HBCG + H2O = BCG- + H3O+ (yellow)(blue)The Ka (the equilibrium constant for the acid) expression is: Ka=[BCG−][H3O+][HBCG]When [BCG-] = [HBCG], then Ka = [H3O+]. If you know the pH of the solution, then the [H3O+] and Ka can be determined. What would be the color of the solution if there were equal concentrations of HBCG and BCG-?Solution Color: _______________What is the pH at the first appearance of this color?Solution pH: __________What is an estimate for the Ka for bromocresol green? Show your work to get full credit
Answer:
At equal concentration of HBCG and BCG^-, the colour is green. This colour first appears at pH = 3.8
Explanation:
HBCG is an indicator that is prepared by dissolving the solid in ethanol.
Since
Ka=[BCG−][H3O+][HBCG]When [BCG-] = [HBCG], then Ka = [H3O+].
If pH = 3.8
Ka= [H3O+] = -antilog pH = -antilog (3.8)
Ka= 1.58 ×10^-4
The abiotic factor is primary source of energy for all organisms.
Answer:
True, abiotic factors are the primary resources.
Answer: The abiotic factor sunlight is the primary source of energy for living organisms.
Explanation: edmentum/plato
What atomic symbol completes this reaction?
238 234.
U →
Th + ?
90
92
Answer:
Correct option is ₂⁴He
Explanation:
Uranium-238 undergo alpha decay and produce Th-234 and alpha particle.
₉₂U²³⁸ → ₉₀Th²³⁴ + ₂He⁴ + energy
Alpha radiations are emitted as a result of radioactive decay. The atom emit the alpha particles consist of two proton and two neutrons. It is also called helium nuclei. When atom undergoes the alpha emission the parent atom converted into the atom having mass number less than 4 and atomic number less than 2 as compared to parent atom.
Properties of alpha radiation:
Alpha radiations can travel in a short distance.
These radiations can not penetrate into the skin or clothes.
These radiations can be harmful for the human if these are inhaled.
These radiations can be stopped by a piece of paper.
To make a ball move faster, you need to increase
The force applied to the ball
The size of the ball
O The mass of the ball
The friction under the ball
Answer:
The force applied to the ball.
Explanation:
Hope this helps!! Good luck!!
“Ozone protects us in the stratosphere but is a pollutant in the troposphere” true or false?
Answer:
true
Explanation:
Answer:
I would say the answer is FALSE because the ozone layer is the common term for the high concentration of ozone that is found in the stratosphere between 15 and 30km above the earth's surface. It covers the entire planet and protects life on earth by absorbing harmful ultraviolet-B (UV-B) radiation from the sun. So if the ozone layer is located at the stratosphere then the answer to your question is FALSE. Most atmospheric ozone is concentrated in a layer in the stratosphere, about 9 to 18 miles (15 to 30 km) above the Earth's surface (see the figure below). Ozone is a molecule that contains three oxygen atoms. At any given time, ozone molecules are constantly formed and destroyed in the stratosphere.
Hope this helps, stay safe and have a great day! :)))))
how many seconds is in 1 year
Explanation:
hope it helps :)
An atom has 9 electrons and 9 protons at the start. If it loses 2 electrons, the net charge on the atom will be
If it loses 2 electrons, the net charge on the atom will be 2. You should first see if the question is already answered next time.
Describe electrons.
Location:
Charge:
mass
Answer:
Describe electrons.
Location: electron cloud
Charge: negative
Mass: one-two thousands amu
Explanation:
Please help!!!!!!!!!!!
Answer:
They both have two valence electrons
Answer:
I am guessing because they are both metals
What do you notice about the pattern of volcanoes?
Answer:
What patterns do volcanoes form?
Volcanoes occur at convergent plate boundaries were subducting oceanic crust is melted. This magma rises through the crust to form volcanoes and volcanic island arcs. Volcanoes occur at divergent plate boundaries where upwelling magma pushes between plates (rift zones) as the plates move apart.
The periodic table says that the average mass of copper is 63.55 but there is no such thing as copper-63.55. Why? (please use copper-63 and copper-64 in your answer)
Answer:
69%for the isotope that weighs 62.93 u and
31
%
for the isotope that weighs 64.93 u.
You can approach this problem by using a single equation; let's say the first isotope contributes to the relative atomic mass by a fraction
x
(
x
<
1
). SInce there are only 2 isotopes to consider, the fraction the other isotope contributes with will automatically be
1
−
x
.
Let's set up the equation
x
⋅
62.93
u
+
(
1
−
x
)
⋅
64.93
u
=
63.55
u
Solving this for
x
will produce
64.93
u
−
63.55
u
=
2
x
→
x
=
1.38
2
=
0.69
Multiplying these fractions (0.69 and 1 - 0.69 = 0.31) by 100% percent to get the results as a percentage will give
69
%
for the isotpe that weighs 62.93u and
31
%
for the one that weighs 64.93u.
Answer link
6th grade help me plzzzzzz
Answer:
It's protons and neutronsExplanation:
Hope this helpsI’m confused on this
Answer:
B
Explanation:
The scientist had a wrong hypothesis?
Answer:
it would be C.
Explanation:
becuase the scientist would know what to to next time for his next experiment. even if it went wrong, he can try to get it right again.
0
Chem
Equations
Balance and Classify each of the following equations into:
Combination reaction, Decomposition Reaction, Single
Replacement reaction, Combustion reaction Double
Replacement reaction
A)
KBr(aq) + Cl2(g) → _ KCl(aq) + Br2(1)
B)
CaBr2(aq)
+ H2SO4(aq) - CaSO4(s) +_HBr(g)
N2(g) + H2(g) + NH3(g)
Grading: Each Equation Balanced --2 points, Classification --
1 point each
Ontime submission ---1 point
DUE: Oct 9, 2020 at 11:00 AM
Answer :
(A) The balanced chemical reaction will be:
[tex]2KBr(aq)+Cl_2(g)\rightarrow 2KCl(aq)+Br_2(l)[/tex]
This reaction is a single replacement reaction.
(B) The balanced chemical reaction will be:
This reaction is a double displacement reaction.
(C) The balanced chemical reaction will be:
[tex]N_2(g)+3H_2(g)\rightarrow 2NH_3(g)[/tex]
This reaction is a combination reaction.
Explanation :
Balanced chemical reaction : It is defined as the reaction in which the number of atoms of an element present on reactant side must be equal to the product side.
Part (A):
The balanced chemical reaction will be:
[tex]2KBr(aq)+Cl_2(g)\rightarrow 2KCl(aq)+Br_2(l)[/tex]
This reaction is a single replacement reaction in which the most reactive element displaces the least reactive element from its solution.
Part (B):
The balanced chemical reaction will be:
[tex]CaBr_2(aq) +H_2SO_4(aq)\rightarrow CaSO_4(s)+2HBr(g)[/tex]
This reaction is a double displacement reaction in which a positive cation and a negative anion of two reactants exchange their places to form two new products.
Part (C):
The balanced chemical reaction will be:
[tex]N_2(g)+3H_2(g)\rightarrow 2NH_3(g)[/tex]
This reaction is a combination reaction in which the two atoms combine to form a larger molecule.
Enter the cycle number, n, in the x column and the number of radioactive atoms in the y column. When you finish, resize the window.
a jaguar can run up to 50 miles per hour, how many feet can he run per second? give your answer in scientific notation to one and three significant figures.
Answer:
50x10^0
Explanation:
For the reactions below, describe the reactor system and conditions you suggest to maximize the selectivity to make the desired species, D, which is a very small molecule. For full credit, support your suggestions with clear calculations, explanations and sketches where appropriate. Rates are in mol/L.s and concentrations are in mol/L. Reaction 1: A+B D -r1A= 10 exp[-8000 K/T]CACB Reaction 2: B+D U -r2B= 109 exp[-10,000 K/T]CBCD BELOW – make sure to note highlighted question number for answers on Exam Paper. 4. Describe the reactor system and conditions: ___ Answer written on Exam paper AND in BB
Answer:
hello your question lacks the required reaction pairs below are the missing pairs
Reaction system 1 :
A + B ⇒ D [tex]-r_{1A} = 10exp[-8000K/T]C_{A}C_{B}[/tex]
A + B ⇒ U [tex]-r_{2a} = 100exp(-1000K/T)C_{A} ^\frac{1}{2}C_{B} ^\frac{3}{2}[/tex]
Reaction system 2
A + B ⇒ D [tex]-r_{1A} = 10exp( -1000K/T)C_{A}C_{B}[/tex]
B + D ⇒ U [tex]-r_{2B} = 10^9exp(-10000 K/T) C_{B}C_{D}[/tex]
Answer : reaction 1 : description of the reactor system : The desired reaction which is the first reaction possess a higher activation energy and higher temperature is required to kickstart reaction 1
condition to maximize selectivity : To maximize selectivity the concentration of reaction 1 should be higher than that of reaction 2
reaction 2 :
description of reactor system : The desired reaction i.e. reaction 1 has a lower activation energy and lower temperatures is required to kickstart reaction 1
condition to maximize selectivity:
to increase selectivity the concentration of D should be minimal
Explanation:
Reaction system 1 :
A + B ⇒ D [tex]-r_{1A} = 10exp[-8000K/T]C_{A}C_{B}[/tex]
A + B ⇒ U [tex]-r_{2a} = 100exp(-1000K/T)C_{A} ^\frac{1}{2}C_{B} ^\frac{3}{2}[/tex]
the selectivity of D is represented using the relationship below
[tex]S_{DU} = \frac{-r1A}{-r2A}[/tex]
hence SDu = 1/10 * [tex]\frac{exp(-800K/T)}{exp(-1000K/T)} * C_{A} ^{0.5} C_{B} ^{-0.5}[/tex]
description of the reactor system : The desired reaction which is the first reaction possess a higher activation energy and higher temperature is required to kickstart reaction 1
condition to maximize selectivity : To maximize selectivity the concentration of reaction 1 should be higher than that of reaction 2
Reaction system 2
A + B ⇒ D [tex]-r_{1A} = 10exp( -1000K/T)C_{A}C_{B}[/tex]
B + D ⇒ U [tex]-r_{2B} = 10^9exp(-10000 K/T) C_{B}C_{D}[/tex]
selectivity of D
[tex]S_{DU} = \frac{-r1A}{-r2A}[/tex]
hence Sdu = [tex]1/10^7 * \frac{exp(-1000K/T)}{exp(-10000K/T)} *\frac{C_{A} }{C_{D} }[/tex]
description of reactor system : The desired reaction i.e. reaction 1 has a lower activation energy and lower temperatures is required to kickstart reaction 1
condition to maximize selectivity:
to increase selectivity the concentration of D should be minimal
Investigating physical and chemical changes takes a plan. Which of the following
are part of planning? Select all that apply.
A. knowing the results of the investigation
B. listing the materials and tools that are needed
C. filling out a data table with the results
D. writing down the procedure for the investigation
E. making sense of what happened to explain it
Answer:
D e
Explanation:
The reaction between ethylene and hydrogen bromide to form ethyl bromide is carried out in a continuous reactor. The product stream is analyzed and found to contain 56.7 mol% C2H5Br and 10.3 mol% HBr. The feed to the reactor conains only ethylene and hydrogen bromide. Calculate the fractional conversion of the limiting reactant and the percentage by which the other reactant is in excess. If the molar flow rate of the feed stream is 265 mol/s, what is the extent of reaction
Answer:
Extent of reaction = 95.9 mol.
Fractional conversion of the limiting reactant = 0.846.
Percentage by which the other reactant is in excess = 25.2 %.
Explanation:
Hello.
In this case, for the undergoing chemical reaction:
[tex]CH_2=CH_2+HBr\rightarrow CH_3-CH_2Br[/tex]
We can write the mole balance per species also including the extent of the reaction:
[tex]CH_2=CH_2:A\\\\HBr: B\\\\CH_3-CH_2-Br:C[/tex]
[tex]x_AP=z_AF-\epsilon \\\\x_BP=z_BF-\epsilon \\\\x_CP=\epsilon[/tex]
Considering that P is the flow of the outlet product. In such a way, writing the data we know, we can write:
[tex]0.33P=z_A*265-\epsilon \\\\0.103P=z_B*265-\epsilon \\\\0.567P=\epsilon[/tex]
Whereas we can replace the C2H5Br mole balance in the others mole balances:
[tex]0.33P=z_A*265-0.567P \\\\0.103P=z_B*265-0.567P\\\\\\z_A*265-0.897P=0\\\\z_B*265-0.67P=0[/tex]
By knowing that [tex]z_B=1-z_A[/tex], we can write:
[tex]z_A*265-0.897P=0\\\\(1-z_A)*265-0.67P=0\\\\\\z_A*265-0.897P=0\\\\-z_A*265-0.67P=-265[/tex]
Thus, solving for P and [tex]z_A[/tex], we obtain:
[tex]z_A=0.572\\\\P=169.11mol[/tex]
It means that the extent of the reaction is:
[tex]\epsilon=0.567P=0.567*169.11mol\\\\\epsilon=95.9mol[/tex]
For the limiting reactant, due to the 1:1 mole ratio between the reactants, it is the one having the smallest flow rate:
[tex]F_A=0.572*265mol=151.58mol\\\\F_B=265mol-151.58mol=113.42mol[/tex]
It means that the limiting reactant is B which is HBr, whose fractional conversion is:
[tex]X_B=1-\frac{0.103*169.11}{113.42mol}\\ \\X_B=0.846[/tex]
Finally, the percentage by which the other reactant is in excess, corresponds to:
[tex]\% excess =(1-\frac{113.42mol}{151.58mol})*100\%\\ \\\%excess=25.2\%[/tex]
Regards.
58:27
1
Dominic made the table below to organize his notes about mixtures
Properties of Mixtures
has no set composition
must have more than one state of matter
must have more than one substance
What mistake did Dominic make?
The title should read "Properties of Solutions" because some mixtures do not have all of the properties listed
O There is a definite recipe to make each mixture, so the composition of a mixture is set.
Although it is possible to have more than one state, it is also possible to have only one state.
O A single substance can be used to make a mixture if the substance is composed of more than one element
Sao and Fit
Answer:
Although it is possible to have more than one state, it is also possible to have only one state.
Explanation:
The mistake Dominic made was stating that "although it is possible to have more than one state, it is also possible to have only one state."
Mixtures are impure substances with the following properties:
They have an indefinite composition
Their constituents retains their identities.
Constituents react differently to changed conditions.
They can easily be separated into constituents by physical methods.
There are two types of mixtures based on the number of phases coexisting:
Homogeneous mixtures have their constituents existing in just one phase.
Heterogeneous mixtures exists in at least two different phases.
Explanation:
In a saturated solution that is in contact with solid Mg(OH)2, the concentration of Mg2 is 1.31 X 10-4M. What is the solubility product for Mg(OH)2
Answer:
Ksp = 8.99x10⁻¹²
Explanation:
The solubility of Mg(OH)₂ is described with the reaction:
Mg(OH)₂(s) → Mg²⁺(aq) + 2OH⁻(aq)
The solubility product, Ksp, is:
Ksp = [Mg²⁺] [OH⁻]²
As you can see from the reaction, when 1 mole of Mg²⁺ is produced, 2 moles of OH⁻ are produced too, if [Mg²⁺] is 1.31x10⁻⁴M, [OH⁻] = 2.62x10⁻⁴M
Replacing:
Ksp = [Mg²⁺] [OH⁻]²
Ksp = [1.31x10⁻⁴M] [2.62x10⁻⁴M]²
Ksp = 8.99x10⁻¹²The solubility product of the [tex]\rm Mg(OH)_2[/tex] has been [tex]\rm 8.99\;\times\;10^{-12}[/tex].
The balanced equation for the dissociation of Magnesium hydroxide has been:
[tex]\rm Mg(OH)_2\;\rightarrow\;Mg^2^+\;+\;2\;OH^-[/tex]
From the balanced chemical equation, dissociation of 1 mole magnesium hydroxide has been resulted in the 1 mole magnesium and 2 mole hydroxide ions.
Since, given magnesium concentration, [tex]\rm Mg^2^+=1.31\;\times\;10^-^4\;M[/tex]
The concentration of hydroxide ion, [tex]\rm OH^-[/tex] will be:
[tex]\rm 1\;M\;Mg^2^+=2\;M\;OH^-\\1.31\;\times\;10^-^4\;M=1.31\;\times\;10^-^4\;\times\;2\;M\;OH^-\\1.31\;\times\;10^-^4\;M=2.62\;\times\;2\;M\;OH^-\\[/tex]
The solubility product (ksp) of the reaction has been given as:
[tex]ksp=\rm [Mg^2^+]\;[OH^-]^2[/tex]
Substituting the values for ksp:
[tex]ksp\;=\rm [1.31\;\times\;10^-^4]\;[2.62\;\times\;10^-^4]^2\\\textit ksp=8.99\;\times\;10^-^1^2[/tex]
The solubility product of the reaction has been [tex]\rm 8.99\;\times\;10^{-12}[/tex].
For more information about solubility product, refer to the link:
https://brainly.com/question/1163248
How do you round 3795 to THREE sig figs?
Answer:
The answer is 380.
Explanation:
Significant figures:
All non-zero digits are consider significant figures like 1, 2, 3, 4, 5, 6, 7, 8, 9.
Leading zeros are not consider as a significant figures. e.g. 0.06 in this number only one significant figure present which is 6.
Zero between the non zero digits is consider significant like 108 consist of three significant figures.
The zeros at the right side e.g 6300 are also significant. There are four significant figures are present.
How to round the value to three significant figures.
First of all we will place the vertical line after 3rd digit.
379/5
Now we will look at the 4th digit. If it is five or more than five then one is added to 3rd digit. If it is less than five the 3rd digit remain same. In given value 4th digit is 5 thus one is added into 9 and the value become 380.
The answer is 380.
A student puts a piece of ice into a beaker of cold water. Which two Statements are true ?A. Thermal energy will move from air to the water. B. Thermal energy will move from the water to the ice. C.Thermal energy will move from the ice to the air . D. Thermal energy will move from the water to the air.
Answer:
C.Thermal energy will move from the ice to the air.
Explanation:
The energy that is associate with the random movement of particles is called thermal energy. The water has a specific heat that is the energy that is needed to raise one gram of a substance to one degree Celsius as water can absorb a large amount of energy and produce a small number of changes the option C.Where does the energy within the greenhouse effect originate?
from convection within the atmosphere
from the circular movement of hot and cold air
from solar radiation entering the atmosphere
from the conduction of heat from the ground to the air
Answer:
from solar radiation entering the atmosphere
Explanation:
The energy within the greenhouse effect is originated from solar radiation entering the atmosphere, hence option C is correct.
What is solar radiation?Solar radiation is a broad word for the electromagnetic radiation that the sun emits. It is also sometimes referred to as the solar resource or just sunshine.
A variety of devices can be used to collect solar radiation and transform it into useful forms of energy, such as heat and electricity.
Heat is reflected into the atmosphere from solar energy that has been absorbed in the earth's surface.
Greenhouse gases absorb a large portion of the heat as it travels through the atmosphere and is radiated back into space.
Therefore, the greenhouse effect is powered by solar radiation that reaches the atmosphere.
Learn more about solar radiation, here:
https://brainly.com/question/23338147
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Cu(NO3)2+Zn(s)>Cu(s)+Zn(NO#)2 is an example of which type of reaction. A) decomposition B) single-displacement C) combustion D) double-displacement
Katiana wanted to figure out what type of liquid worked best for growing beans. She watered one with coca-cola, one with lemonade, and one with just water. After one week, she measured how high they had grown. Independent Variable (What I, the scientist test or change) *
Question 1 (5 points)
Calculate the frequency of a photon that exhibits a wavelength of 451 nm.
Equation: E = hu
h = 6.63 x 10-34]'s
Answer:
e
Explanation:
what would happen to global temperatures of solar energy was unbalanced
Answer:
mostly skin diseases
Explanation:
because of greenhouse effects
True or False – When earthquakes occur, they form huge gaps in the earth’s surface.
Answer:
i think the answer is true pls mark branliest
Explanation:
Answer:
its true! earth quakes do form huge gaps in the earth surface
Explanation:
