Answer: Pb(NO3)2(aq) + 2KI(aq) —> PbI2(s) + 2KNO3(aq)
Explanation:
A phosphate buffer is prepared with KH2PO4 at 0.02 M and K2HPO4 at 0.03 M. What is the concentration of phosphate buffer
Answer:
0.05M is the concentration of the phosphate buffer
Explanation:
A buffer is defined as the aqueous mixture of a weak acid (KH₂PO₄) and its conjugate base (K₂HPO₄). The concentration of this buffer is the sum of the concentrations of the weak acid and the conjugate base, that is:
Concentration of phosphate buffer = 0.02M + 0.03M
=
0.05M is the concentration of the phosphate buffer
What mass of water in grams will fill a tank 126cm long, 47 cm wide, and 13 cm high
Answer:
Mass = 76986 g
Explanation:
Given data:
Dimensions of tank = 126 cm× 47 cm× 13 cm
Mass of water required to filled = ?
Solution:
First of all we will calculate the volume of tank which is equal to the volume of water required to fill it.
Volume = length ×height ×width
Volume = 126 cm × 13 cm× 47 cm
Volume = 76986 cm³
Mass of water:
Mass = density × volume
density of water is 1 g/cm³
Mass = 1 g/cm³× 76986 cm³
Mass = 76986 g
Which refers to any disturbance that carries energy from one place to another? wave trough motion crest
Answer:
Wave
Explanation:
Wave refers to any disturbance that carries energy from one place to another.
What is wave?Wave refers to disturbance or variation that occur in a body travelling or in motion which travels from one medium to another by transmitting energy from one location which is the origin to another location without transporting matter.
Therefore, Wave refers to any disturbance that carries energy from one place to another
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identify the equipment best suited for extinguishing each type of fire. Your choices are: fire extinguisher, overturned beaker, fire blanket.
Answer: The equipment best suited for extinguishing each type of fire are listed below:
--> Fire extinguisher: Large fire on the floor
--> Overturned beaker: Small benchtop fire
--> Fire blanket: clothing fire.
Explanation:
Fire outbreaks is a common event that can be prevented in a standard chemistry laboratory with the aid of fire safety equipments.
The method used by these equipments to extinguish fire is to suffocate the fire by obstructing the source of oxygen, by reducing the heat with the use of water and removing the fuel or oxygen source.
These fire safety equipments should be highly visible and easily accessible in a laboratory. Example of fire safety equipments includes:
--> Fire extinguisher: A laboratory personnel needs to be trained in the use of this since it's made up of different types. it can be used to extinguish ( put out) large fire on the floor.
--> Overturned beaker: this can be used to suffocate small fire on the bench which is also common in the laboratory.
-->Fire blanket: This should be used in the event that a person’s body or clothing catches fire.
Please help me on this
Where would a disease transmitted by person to person contact be most likely to spread quickly
Answer: inside
Explanation:
Answer:
direct and indirect contact
Explanation:
if you touch a doorknob right after an infected person than you make be exposed to the disease.
The concentration of lithium chlorite solution is 12.0% by mass. In a ___g sample of this solution, there are 238.5g of dissolved lithium chlorate.
Answer is A) 1990 but I do not know to go to there please help!
Mass of sample : 1987.5 g≈1990 g
Further explanationGiven
12% mass of Lithium chlorate
Required
Mass of sample
Solution
%mass = (mass of solute/mass of solution) x 100%
mass of solute = mass of Lithium chlorate = 238.5 g
Input the value :
12/100(0.12) = 238.5 g : mass of solution
mass of solution =238.5 : 0.12
mass of solution = 1987.5≈1990 g
Which of the following is the poorest conductor of electricity?
Calcium (Ca)
Silicon (Si)
Fluorine (F)
Sodium (Na)
Cobalt (Co)
Answer:
Fluorine (F)
Explanation:
The poorest conductor of electricity from the given choices is fluorine. This is because fluorine is a non - metal.
Like other non - metals, fluorine does not conduct electricity.
Only metals are known to conduct electricity and heat readily.
Semi - metals like silicon will conduct electricity under specific condition.
The free mobile electrons in metals makes it easy for them propagate electricity
An average reaction rate is calculated as the change in the concentration of reactants or products over a period of time in the course of the reaction. An instantaneous reaction rate is the rate at a particular moment in the reaction and is usually determined graphically, but it can also be calculated using calculus. The reaction of compound A forming compound B was studied and the following data were collected:
Time (s) [A] (M)
0. 0.184
200. 0.129
500. 0.069
800. 0.031
1200. 0.019
1500. 0.016
Required:
a. What is the average reaction rate between 0 and 1500s?
b. What is the average reaction rate between 200. and 1200s ?
c. What is the instantaneous rate of the reaction at t=800s?
Answer:
Explanation:
a )
Average reaction rate between 0 and 1500s
Time duration = 1500 s
moles reacted = .184 - .016 = .168 moles
Moles reacted per second = .168 / 1500
= 112 x 10⁻⁶ moles /s
b )
Average reaction rate between 200 and 1200s
Time duration = 1000 s
moles reacted = .129 - .019 = .11 moles
Moles reacted per second = .11 / 1000
= 110 x 10⁻⁶ moles /s
c )
the instantaneous rate of the reaction at t=800s
We shall assume that between 500 s and 1200 s , rate of reaction is uniform
rate between 500 and 1200
Time duration = 700 s
moles consumed = .069 - .019 = .05 moles
Rate of reaction = .05 / 700
= 71 .4 x 10⁻⁶ moles / s
This will also be instantaneous rate of reaction at t = 800 s .
first response gets brainliest
Given the equation:
4Al2O3 + 9Fe --> 3Fe3O4 + 8Al
If 27.5 g of Al2O3 reacted with 8.4 g of Fe, how many of Fe 3O4 are formed?
a) Calculate the limiting reactant
b) Calculate the number of grams of Al produced.
c) Calculate the number of grams of Fe3O4 produced.
d) Calculate the percent yield if 10g of Fe O4 were obtained?
Answer: a) [tex]Fe[/tex] is the limiting reagent
b) 3.59 g
c) 11.6g
Explanation:
[tex]4Al_2O_3+9Fe\rightarrow 3Fe_3O_4+8Al[/tex]
To calculate the moles :
[tex]\text{Moles of} Al_2O_3=\frac{27.5g}{102g/mol}=0.27moles[/tex]
[tex]\text{Moles of} Fe=\frac{8.4g}{56g/mol}=0.15moles[/tex]
According to stoichiometry :
a) 9 moles of [tex]Fe[/tex] require= 4 moles of [tex]Al_2O_3[/tex]
Thus 0.15 moles of [tex]Fe[/tex] will require=[tex]\frac{4}{9}\times 0.15=0.067moles[/tex] of [tex]Al[/tex]
Thus [tex]Fe[/tex] is the limiting reagent as it limits the formation of product and [tex]Al[/tex] is the excess reagent.
b) As 9 moles of [tex]Fe[/tex] give = 8 moles of [tex]Al[/tex]
Thus 0.15 moles of [tex]Fe[/tex] give =[tex]\frac{8}{9}\times 0.15=0.133moles[/tex] of [tex]Al[/tex]
Mass of [tex]Al=moles\times {\text {Molar mass}}=0.133moles\times 27g/mol=3.59g[/tex]
c) As 9 moles of [tex]Fe[/tex] give = 3 moles of [tex]Fe_3O_4[/tex]
Thus 0.15 moles of [tex]Fe[/tex] give =[tex]\frac{3}{9}\times 0.15=0.05moles[/tex] of [tex]Fe_3O_4[/tex]
Mass of [tex]Fe_3O_4=moles\times {\text {Molar mass}}=0..05moles\times 231.5g/mol=11.6g[/tex]
How do plate tectonics affect mountains?
Mountains outline plate tectonic boundaries.
Plate tectonics spreading can create mountains.
Plate tectonic collisions can create mountains.
Mountains provide evidence for plate tectonics.
Answer:
C. Plate tectonic collisions can create mountains.
Answer:
They can make them larger
Explanation:
They go up under a mountain and then the mountains rise up
Allows ingestion and breaks down food so that nutrients can be absorbed???
Answer:
Salivation allows the ingestion of food while digestive juices aids breakdown of food and absorption of nutrients.
Explanation:
When food is taken into the mouth, the presence of food triggers a nervous reflex that causes the salivary gland to produce saliva in the mouth. Once the food particles have been ingested the digestive system breaks down the food into smaller components with the aid of the digestive juices.
Consider the following chemical equilibrium:
NH4SH(s) ⇌ H2SgNH3(g) Now write an equation below that shows how to calculate Kp from Kc for this reaction at an absolute temperature T. You can assume T is comfortably above room temperature. If you include any common physical constants in your equation be sure you use their standard symbols, found in the ALEKS Calculator.
Answer:
See explanation below
Explanation:
First, let's write the reaction:
NH₄SH(s) <------> H₂S(g) + NH₃(g)
The reaction is already balanced so we don't need to do anything else.
Second, let's take into account the following. The Kc expression for this reaction, only compounds in gaseous state are the only ones that contribute to the equilibrium. Solid and liquid do not contribute to the Kc expression. This is because solid and liquid have a constant concentration near to 1, so, it won't do any difference.
Knowing this, the Kc expression for this reaction is:
Kc = [H₂S] [NH₃]
Now, to calculate Kp from Kc, there's an expression that helps a lot to do this. The expression is the following:
Kp = Kc (RT)ᵃⁿ (1)
Where:
R: universal constant of gases
T: Temperature in K
ᵃⁿ = difference of the coefficients of the reaction.
This expression comes from the fact that Kp is an expression that instead of working with concentrations, it works with pressure.
If we use the ideal gas equation we have:
PV = nRT
Solving for P:
P = nRT/V and C = n/V so
P = CRT
If we now replace this, in the Kp expression of equilibrium we have:
Kp = pH₂S * pNH₃
Kp = ([H₂S]RT)¹ ([NH₃]RT)¹
Kp = (RT)¹⁺¹ ([H₂S] [NH₃])
Kp = (RT)²Kc
So finally the expression for Kp would be:
Kp = Kc (RT)²Hope this helps
In general, weathering tends to occur more rapidly in warm climates than in cool climates. How does this trend explain the effect of temperature on erosion rates?
Answer:
See explanation
Explanation:
Weathering refers to the breakdown of rocks to form soil. There are several agents of weathering.
In warmer regions, there are more vegetation and microorganisms and they increase the rate of biological weathering.
Since weathering leads to the formation of soil and the rate of weathering is greater in warmer climates, it also follows that as temperature increases and more soil is formed, erosion will happen faster at this higher temperature owing to the presence of more soil compared to colder climates.
There is a huge and direct effect of temperature on the rates of erosion.
The highest rate of weathering occurs in warm and wet climate because in warm and wet climatic regions, more rainfall occurs which increase the rate of weathering. Rainfall and temperature can affect the rate in which rock weathering occurs.
High temperatures and greater rainfall increase the rate of chemical weathering. Rocks in tropical regions exposed to abundant rainfall so we can conclude that hot temperatures weather much faster than similar rocks residing in cold, dry regions.
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ASAP I WILL GIVE BRAINLIEST The diagram shows a lever. What is the mechanical advantage of the lever? O 2 03 3 m 6 m mi 0 9
Answer:
A) 2
Explanation:
Answer:
2, i got it right thanks to the other user :) <3
Explanation:
if LiCl and MgBr2 were to enter into a chemical reaction which member of MgBr2 will chlorine replace?
Answer:
It replaces Br in MgBr2.
Explanation:
Hello!
In this case, when carrying out double displacement reactions, we need to take into account that cations and anions are switched; thus, when LiCl and MgBr2 react, since Li and Mg are the cations, Br and Cl switch as shown below:
[tex]2LiCl+MgBr_2\rightarrow 2LiBr+MgCl_2[/tex]
Thus, chlorine replace Br in MgBr2 to form MgCl2.
Best regards!
What is the atomic number?
pls help.
Answer:
8
Explanation:
If 1.546 g of copper was used by a student at the start of the lab, and 0.732 g of copper were obtained at
the end of the series of reactions, what was the percent recovery? Briefly explain how you found your
answer.
Answer: Percent recovery is 47.34 %
Explanation:
Percent yield is defined as the ratio of experimental yiled to theoretical yield in terms of percentage.
[tex]{\text{ percent yield}}=\frac{\text{amount recovered}}{\text{total amount}}\times 100[/tex]
Putting in the values we get:
[tex]{\text{ percent yield}}=\frac{0.732}{1.546}\times 100=47.34\%[/tex]
Therefore, the percent recovery is 47.34 %
Benzophenone has a normal freezing point of +48.1 oC, with freezing point depression constant Kfpt = − 9.78 oC/m. A 0.1500 molal solution of ionizing salt had a freezing point of +44.0 oC. What is the van't Hoff (ion dissociation) constant i for this salt? (i.e., the average number of ions produced in the solution.) Report 3 significant digits.
Answer:
i = 2.79
Explanation:
The excersise talks about the colligative property, freezing point depression.
Formula to calculate the freezing point of a solution is:
Freezing point of pure solvent - Freezing point of solution = m . Kf . i
Let's replace data given. (i = Van't Hoff factor, numbers of ions dissolved in solution)
48.1°C - 44°C = 0.15 m . 9.78°C/m . i
4.1°C / (0.15 m . 9.78°C/m) = i
i = 2.79
In this case, numbers of ions dissolved can decrease the freezing point of a solution, which is always lower than pure solvent.
Cleavage refers to the way a rock:
A. shine
B. breaks
C. streaks
D. is made
Explanation:
Türküm ben yanlisikla siteye girdim.
Answer:
breaks
Explanation:
I think its braks
The number of atoms in 10. grams of calcium is equal to 6.0 x 1023 multiplied by which number?
Answer:
1.51×10²³ atoms.
Explanation:
From the question given above, the following data were obtained:
Mass of Calcium (Ca = 10 g
Number of atom of Calcium (Ca) =?
The number of atoms present in 10 g of Ca be obtained as follow:
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ atoms. This implies that 1 mole Ca contains 6.02×10²³ atoms.
1 mole of Ca = 40 g.
Now, if 40 g of Ca contains 6.02×10²³ atoms.
Therefore, 10 g of Ca will contain = (10 × 6.02×10²³) / 40 = 1.51×10²³ atoms.
Thus, 10 g of calcium contains 1.51×10²³ atoms.
Which pair of elements would you expect to exhibit the greatest similarity in their physical
and chemical properties?
Select one:
O a. No
O b. Mg, Al
O c. Br, Kr
O d. As, Br
O e. I, AT
Answer:
e. I, At
Explanation:
Hello!
In this case, since the periodic trends of a series of elements belonging to the same group towards physical and chemical properties tend to be the same when closer in period, we notice that Mg and Al, Br and Kr and As and Br are close but in period, not in the same group; therefore e. I, At, iodine and astatine, are going to tend to exhibit the greatest similarity in their physical and chemical properties.
Best regards!
How did fossil records support the existence of a supercontinent?
Similar fossils provided evidence that a meteor hit Earth.
Similar fossils were found in different continents.
Fossil records showed how old the continents were.
Fossil records provided evidence that dinosaurs existed.
Answer:
B. Similar fossils were found in different continents.
Answer:
B. Similar fossils were found in different continents.
Explanation:
table salt conducts electricity in water, but sugar does not. Explain why?
Answer:
Because sugar has no ions in the solution
Explanation:
Pure water contains very few ions, so it does not conduct electricity very well. When table salt is dissolved in water, the solution conducts very well, because the solution contains ions. When sugar is dissolved in water, the solution does not conduct electricity, because there are no ions in the solution.
In basic words the more ions in the solution there is a better chance to conduct electricity.
Where could convection currents form?
A. in a sand dune
B. on a pavement
C. in the atmosphere
D. in outer space
IM TIMED PLS HELP
Answer:
D. In the atmosphere
Explanation:
convection currents forms in the atmosphere
Which statement defines the enthalpy of solution?
the total number of particles in a solution
the phase change from a solid to a liquid
o the difference in characteristics between reactants and products
the change in energy when one substance dissolves in another
Answer:
the change in energy when one substance dissolves in another
Explanation:
The enthalpy changes are the heat changes accompanying physical and chemical changes. Actually, an enthalpy change is the difference between the sum of the heat contents of products (final state) and sum of the heat contents of reactants (initial state).
There are basically two types of heat changes that accompanies are reaction which are:
Exothermic changes Endothermic changesTherefore, the change in energy when one substance dissolves in another defines the enthalpy of solution.
Enthalpy of solution is the heat liberated or absorbed when one mole of a substance (solute) is dissolved in a specified volume of solvent (water).
What is another name for infrared energy? Choose all that apply.
Question 1 options:
Microwave energy
Visible light
Thermal energy
Heat
Answer: not 100% but maybe Visable Light...sorry if thats wrong
Explanation:
Thermal energy is the another name for infrared energy.
What is infrared radiation?Infrared radiation is a type of radiant energy that is not visible to human eyes but we can feel as heat energy.
Infrared radiation (IR), also known as thermal radiation. It is that band of energy in the electromagnetic radiation spectrum with wavelengths between 780 nm and 1 mm so we can conclude that thermal energy is the another name for infrared energy.
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Given:
BO3 + 3Mg → 3MgO + B
1. How many moles of Mg are required if 2 moles of B are produced?
Answer:
6moles of Mg
Explanation:
The reaction expression is given as:
BO₃ + 3Mg → 3MgO + B
Given:
Number of moles of B produced = 2 moles
Unknown:
Number of moles of Mg required = ?
Solution:
From the balanced reaction expression:
1 mole of B is produced from 3 moles of Mg
2 moles of B will be produced from 2 x 3 = 6moles of Mg
How can the IR spectrum be used to show that there is not starting material left and the products are alcohols
Answer:
hello your question is incomplete attached below is the complete question
answer :
Absence of c = c = C-H of the peak and the presence of -O-H and C-O peak shows that there is presence of Alcohols as products and it also shows that there is no starting material left
Explanation:
To provide that there is no starting material left and products are alcohols using the IR spectrum we will apply hydroboration oxidation
Absence of c = c = C-H of the peak and the presence of -O-H and C-O peak shows that there is presence of Alcohols as products and it also shows that there is no starting material left
attached below is the detailed solution
