Answer: B
Explanation:
Mg and Cl are in the same row aka period. Elements in the same period have similar properties like electron shells so the second option is the best answer
How is active immunity different from passive immunity? Give examples of both active and passive natural and artificial immunity.
In the lab you react 20g of potassium iodide with an excess of lead (II) nitrate to form 15g of lead (II) iodide precipitate. What is the percent yield of your experiment?
What is the balanced equation for this question?
What is the first ratio used to solve this question?
What is the second ratio used to solve this question?
What is the third ratio used to solve this question?
What is the percentage yield?
Answer:
C
Explanation:
A solution of NaF is added dropwise to a solution that is 0.0173 M in Ba 2. When the concentration of F- exceeds___M BaF2 will precipiate. Neglect volume changes. For BaF2
Answer:
0.0099M = [F⁻]
Explanation:
For BaF2, Ksp = 1.7x10⁻⁶
When BaF₂ is in solution, the equilibrium between the solid and the dissociated ions occurs as follows:
BaF₂(s) ⇄ Ba²⁺(aq) + 2F⁻(aq)
Where Ksp = 1.7x10⁻⁶ is defined as:
1.7x10⁻⁶ = [Ba²⁺] [F⁻]²
Where [] are equilibrium concentrations of each ion in solution.
That means you will add F⁻ until its concentration exceeds:
1.7x10⁻⁶ = [0.0173] [F⁻]²
9.827x10⁻⁵ = [F⁻]²
0.0099M = [F⁻]When more F⁻ is added, BaF₂ begins its precipitation.
Each of the two different solids A and B melts at 133 o C. A sample of an unknown solid melts around 133 o C, and is either A or B. How will you determine the identity of the unknown solid
Answer:
See explanation
Explanation:
The melting point range of a pure compound is about 1-2ºC of the expected melting point. An impure solid melts within a range that is both larger than that of the pure substance (>1ºC) and begin at a lower temperature because impurities decrease the meting point. A melting range of 5º or more indicates that a compound is impure.
Since the melting points of A and B are estimated at 133 o C, the melting point range for each pure substance must be slightly different from each other. The melting point of the unknown is measured and its range is compared with the melting point ranges of pure A and B then decision can now be made about the identity of the unknown solid.
A particular reaction has an enthalpy and entropy of reaction of ∆H = +33 kJ/mol and ∆S = +0.15 kJ/mol⋅K. At the three indicated temperatures, determine if either reactants or products are favored?
Answer:
Explanation: check my paage
While setting up a beaker to boil a solution on a hot plate, you notice that the stirring is erratic and unstable. What should you do to stabilize the stirring solution? a. Clamp the beaker in place at the edge of the hot plate. b. Move the beaker to the center of the hot plate. c. Turn down the stirring speed. d. Completely turn off the stirring function.
Answer:
B. Move the beaker to the center of the hot plate
Explanation:
The erratic and unstable stirring might be caused by the beaker not being properly balanced on the hot place, there by distorting the the center of gravity of the stirring motion.
In properly positioning the stirrer to the hot plate, the magnetic rod is positioned to the center of the fluid, allowing for a more fluid and even effective stirring.
I hope this was helpful.
The density of osmium (the densest metal) is 22.57 g/cm3.
What is the mass of a block of osmium with dimensions:
4.22 cm x 3.62 cm x 1.41 cm?
Answer: mass = 485 grams approximately
=======================================================
Work Shown:
First we need the volume of the block
volume = (length)*(width)*(height)
volume = (4.22)*(3.62)*(1.41)
volume = 21.539724
volume = 21.5 cubic cm
I'm rounding to three sig figs because each of the dimensions are to three sig figs.
--------------------------
Now turn to the formula
density = mass/volume
This can be rearranged to
mass = density*volume
Plug in the given density and the volume we found earlier to get
mass = density*volume
mass = (22.57)*(21.5)
mass = 485.255
mass = 485 grams
I'm rounding to three sig figs because it's the smaller sig fig count of 22.57 and 21.5
How many more electrons are there in the last energy level of phosphorus, atomic
number 15, than there are in the last principal energy level of neon, atomic number 10?
sorry but I need some three point so that's why I didn't
Which lists the elements in order from least conductive to most conductive?
Answer:
Answer. Answer: Nitrogen (N), antimony (Sb), bismuth (Bi) is the order from least conductive to most conductive.
Answer:
nitrogen (N), antimony (Sb), bismuth (Bi)
What does Hess's law state can be done in order to be able to react solid magnesium with oxygen gas safely (that is, without exposing the magnesium to flames)?A. More moles of solid magnesium can be added until the reaction is safe.B. More moles of oxygen gas can be added until the reaction is safe.C. The reaction can be broken down and performed in steps. D. The phase state of the reactants can be changed to match each other.E. The phase state of the products can be changed to match each other.
Answer:
C. The reaction can be broken down and performed in steps
Explanation:
Hess's Law of Constant Heat Summation states that irrespective of the number of steps followed in a reaction, the total enthalpy change for the reaction is the sum of all enthalpy changes corresponding to all the steps in the overall reaction. The implication of this law is that the change of enthalpy in a chemical reaction is independent of the pathway between the initial and final states of the system.
To obtain MgO safely without exposing magnesium to flame, the reaction sequence shown in the image attached may be carried out. Since the enthalpy of the overall reaction is independent of the pathway between the initial and final states of the system, the sum of the enthalpy of each step yields the enthalpy of formation of MgO.
Which two bonds are most similar in polarity? Which two bonds are most similar in polarity? O-F and Cl-F B-F and Cl-F I-Br and Si-Cl Al-Cl and I-Br C-Cl and Be-Cl
Answer:
A
Explanation:
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The branch of science which deals with chemicals and bonds is called chemistry.
The correct answer is A.
The polarity is defined as the separation of electric charge leading to a molecule or its chemical groups having an electric dipole moment, with a negatively charged end and a positively charged end.
The polar molecule has the following:-
Difference in electronegativity.In, the first compound the polarity is the same because the compound is the same that is O-F and CL-F.
Hence, the correct answer is A.
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Once a rate law is determined from trials with concentration and rate data, what is the minimum number of additional trials that will have to be done to gather sufficient initial rates data to be able to find the rate constant for the reaction? a. 0b. 1c. 2d. 3
Answer:
A is probably ur answer
Explanation:
but if I'm wrong My bad and at least I tried
1.For Structure B the bond between carbon and sulfur is polar or non polar
2. Explain you’re answer
Answer:
polar
Explanation:
because carbon and sulfur have different electronegativities, the S=C bond is polar.
The entire molecule is nonpolar however because the dipoles (polar bonds) cancel out due to the geometry of the molecule (linear)
Chem Muti Choice. Tell me the correct answer.
Answer:
my gues is red not a 100% but its in the 700s
Explanation:
according to the conveyor belt mode of ocean circulation, what happens when water reaches the poles
Answer: Some salt is trapped between ice crystals, but most are left behind in the unfrozen seawater.
Explanation:
Answer: The salinity of the water increases
Explanation: Hope this helps!
For at least the last century Florida has experienced a hurricane season every year, from June to November. Which of the following describes this occurrence the BEST?
A. Florida's precipitation
B. Florida's global pattern
C. Florida's climate
D. Florida's weather
Answer:
Florida's Global Pattern.
Explanation:
Because of where Florida sits, the weather in the Gulf of Mexico actually blows enough water to Create tidal waves, and also hurricanes. at least that's what I was told cause I live here :>
1. A 0.130 M solution of a weak base is titrated with a 0.130 M HCl solution. After the addition of 8.50 mL of the HCl solution to 25.00 mL of the weak base solution, the pH of the solution is 9.36 . Determine the pKb of the weak base.2. Calculate the pH of the resulting solution if 23.0 mL of 0.230 M HCl(aq) is added to (a) 33.0 mL of 0.230 M NaOH(aq).
Answer:
1. 4.93 = pKb of the weak base
2. pH = 12.61
Explanation:
1. When a weak base, B, is being titrated with HCl, the reaction occurs as follows:
B + HCl → BH⁺ + Cl⁻
That means the moles added of HCl are the moles of BH⁺ produced and moles of B are initial moles of B - Moles of HCl
Thus:
Moles B:
Initial moles:
0.0250L * (0.130mol / L) = 3.25x10⁻³ moles B
Moles HCl:
8.5x10⁻³L * (0.130mol / L) = 1.105x10⁻³ moles HCl
3.25x10⁻³ - 1.105x10⁻³ =
2.145x10⁻³ moles BMoles BH⁺ = Moles HCl:
1.105x10⁻³ moles BH⁺pH of the buffer made from B/BH⁺ is determined using H-H equation for weak bases:
pOH = pKb + log [BH⁺] / [B]
Where pOH is 14-pH = 14-9.36 = 4.64
pKb is pKb of the weak base, our unknown.
[BH⁺] could be taken as moles of BH⁺ = 1.105x10⁻³ moles
And [B] as moles of B = 2.145x10⁻³ moles B
Replacing:
pOH = pKb + log [BH⁺] / [B]
4.64 = pKb + log [1.105x10⁻³ moles] / [2.145x10⁻³ moles]
4.64 = pKb -0.288
4.93 = pKb of the weak base2. When HCl and NaOH are in solution the reaction that occurs is:
HCl + NaOH → H₂O + NaCl
To find pH we need to determine, first, which reactant is in excess:
Moles HCl:
0.023L * (0.230mol / L) = 5.29x10⁻³ moles
Moles NaOH:
0.033L * (0.0230mol / L) = 7.59x10⁻³ moles
That means NaOH is in excess and after the reaction will remain:
7.59x10⁻³ moles - 5.29x10⁻³moles = 2.3x10⁻³ moles NaOH = Moles of OH⁻
In 23+33mL = 56mL = 0.056L:
2.3x10⁻³ moles OH⁻ / 0.056L = 0.0411M [OH-]
As pOH = -log [OH-]
pOH = 1.39
pH = 14 - pOH
pH = 12.61Calculate the pH of a buffer solution when 32.0 mL of a 0.25 M H2CO3 is mixed with 20.0 mL of a 0.15 M NaHCO3
pH of buffer solution : 4.32
Further explanationA buffer solution is a solution that can maintain a good pH value due to the addition of a little acid or a little base or dilution.
The buffer solution can be acidic or basic
Acid buffer solutions consist of weak acids(H₂CO₃) and their salts.(NaHCO₃)
mol H₂CO₃
[tex]\tt 0.032\times 0.25=0.008[/tex]
mol NaHCO₃
[tex]\tt 0.02\times 0.15=0.003[/tex]
[tex]\tt [H^+]=Ka\dfrac{mole~weak~acid}{mole~salt}\\\\(H^+]=1.8\times 10^{-5}\dfrac{0.008}{0.003}=4.8\times 10^{-5}\\\\pH=5-log~4.8=4.32[/tex]
In a closed system, the total energy before an energy transformation is _______ the total energy after it.
A.
less than
B.
equal to
C.
unrelated to
D.
greater than
In a closed system, the total energy before an energy transformation is greater than the total energy after it.
What is a closed system ?A closed system is a natural physical system that does not permit the movement of matter into or out of the system, while energy transfer is permitted in some situations, such as those found in physics, chemistry, or engineering.
A closed system is one that only allows the flow of energy; it forbids the exchange of matter. The heat can transfer when we boil water with a closed cover, but the matter cannot.
In a closed system, the overall energy is constant. The universe's overall energy is always changing. Mass may be used to store energy. In a closed system, energy may be transformed from one form to another.
Thus, option D is correct.
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I need help, due in 30 mins
Answer:
1.Reaction rate is how fast a chemical reaction proceeds.
2.Nature of the reaction, Pressure factor
, Solvent, Catalyst and inhibitors.
3.Physical change is a temporary change. A chemical change is a permanent change. A Physical change affects only physical properties i.e. shape, size, etc.
4. One example of the effect of temperature is the use of lightsticks or glowsticks.
5.When the particle size of a fixed mass of a solid reactant becomes smaller, the total exposed surface area becomes larger, the rate of reaction increases. an example could be ice and water when the atoms are stuck together a solid but all over the place as a liquid.
6. Sometimes a reaction depends on catalysts to do their job. In that case, changing the concentration of the catalyst can speed up or slow down the reaction. For example, enzymes speed up biological reactions, and their concentration affects the rate of reaction.
7.A catalyst is a chemical substance that affects the rate of a chemical reaction by altering the activation energy required for the reaction to proceed. For example, a catalyst could cause a reaction between reactants to happen at a faster rate or at a lower temperature than would be possible without the catalyst.
Explanation:
I hope this helps have a great day! :)
Consider the following equations: 3A + 6B â 3D ÎH = â418 kJ E + 2F â A ÎH = â118.2 kJ C â E + 3D ÎH = â60.8 kJ Suppose the first equation is reversed and multiplied by 1/6, the second and third equations are divided by 2, and the three adjusted equations are added. What is the net reaction and what is the overall heat of this reaction?
Answer:
The net reaction is:
1/2 C + F + → A + B D
The overall heat of this reaction = 40.96 kJ
Explanation:
Given that:
3A + 6B → 3D ΔH = -418 kJ
E + 2F → A ΔH = -118.2 kJ
C → E + 3D ΔH = 60.8 kJ
The first process says we should reverse the first equation and multiply it by 1/6
i.e.
3D × 1/6 → 3A × 1/6 + 6B × 1/6 ; ΔH = +1/6 × 418 kJ
1/2D → 1/2 A + B ; ΔH = 69.66 kJ
Then the second and the third equation are divided by 2
1/2 × E + F → 1/2 A ; ΔH = -1/2 × 118.2 kJ
1/2C → 1/2 E + 3/2 D ; ΔH = 1/2 × 60.8 kJ
By adjusting the three equations together; we have:
1/2D → 1/2 A + B ; ΔH = 69.66 kJ
1/2 × E + F → 1/2 A ; ΔH = -59.1 kJ
1/2C → 1/2 E + 3/2 D ; ΔH = 30.4 kJ
1/2C + F → A + B + D ; ΔH = (69.66 - 59.1 + 30.4) kJ
ΔH = 40.96 kJ
The net reaction is:
1/2 C + F + → A + B D
The overall heat of this reaction = 40.96 kJ
What is the kinetic energy of a ball with a mass of 0.5 kg and a velocity of 10 m/s? (Formula:) 25 J 5 J 50 J 100 JWhat is the kinetic energy of a ball with a mass of 0.5 kg and a velocity of 10 m/s? (Formula:) 25 J 5 J 50 J 100 J
Answer:
25J
Explanation:
K.E = 1/2mv^2
= 1/2*0.5*10^2
= 25J
The kinetic energy of the ball is 25 J
What is kinetic energy?Kinetic energy can be defined as the energy possessed by an object in motion. Mathematically, it can be expressed as:
KE = ½mv²
How to determine the kinetic energyFrom the question given above, the following data were obtained:
Mass (m) = 0.5 KgVelocity (v) = 10 m/sKinetic energy (KE) =?KE = ½mv²
KE = ½ × 0.5 × 10²
KE = 0.25 × 100
KE = 25 J
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An igneous intrusion show that a magma body emerged in a stratigraphic section. This magma body is _____ than the rocks around it.
A) older
B) the same age
C) newer
Answer:
Younger/newer
Explanation:
Stratagraphic means an intrusion or fault is younger than the layer it affects.
How many molecules are in Na2CrO4
Answer:
It is 161.97324 g/mol
1 molecule
Will the boiling point of water be higher or lower in the maintains, where the altitude is high, and the pressure is low ?
What happens when this match is struck against the side of the match box?
Answer:
It lights on fire
Explanation:
The friction sparks the match causing it to go on fire.
What elements make up hydrogen peroxide?
Answer:
Hydrogen peroxide is a highly reactive chemical containing the elements hydrogen and oxygen. Pure hydrogen peroxide is a colourless liquid, but it is sold on the market as solutions in water, containing up to 33 – 37% pure hydrogen peroxide and other additives to stop the product decomposing.
Explanation:
Hope this helps <3
Which statement describes how phase changes
can be diagrammed as a substance is heated?
The phase is on the y-axis and thew
temperature is on the x-axis.
The temperature is on the y-axis and the
phase is on the x-axis.
The time is on the y-axis and the temperature
is on the x-axis.
The temperature is on the y-axis and the time
is on the x-axis
Answer: D
Explanation:
On edge
Answer:
D
Explanation:
just did it on Ed
Calculate the amount of heat (in J) needed to raise the temperature of 3.50 g of water from 22.4oC to 98.8oC.
Answer:
76.4oC or 169.52oF
Explanation:
That's the amount of heat needed
The heat capacity is the heat amount lost or gained by the object in a thermodynamic system. The heat needed to raise the temperature of the water is 1117.7 Joules.
What is heat capacity?Heat capacity (q) is the heat an object loses or gains to alter the temperature of the thermodynamic system by a difference of a degree Celsius. The heat capacity is given by the mass, specific heat capacity, and temperature change.
Given,
Mass of water (m) = 3.50 gm
Specific heat (c) = 4.18 J/ g°C
The temperature change (∆T) = T₂ - T₁
= 98.8 °C - 22.4 °C
= 76.4 °C
The heat capacity is given as,
q = mc∆T
Substituting values above:
q = 3.50 gm × 4.18 J/ g °C × 76.4 °C
q = 1117.7 J
Therefore, 3.50 g of water has a heat capacity of 1117.7 Joules.
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A student combines a sample of gas (2.0 L) at 3.5 atm with with another gas (1.5 L) at 2.8 atm pressure into an empty 7.0 L flask. Assuming the gases are combined at constant temperature, what is the total gas pressure (in atmospheres) in the 7.0 L flask?
Answer:
Total gas pressure is 1.60 atm
Explanation:
To solve this question we can use the Ideal Gases Law. We need to determine how many moles of each gas will be finally present at the flask of 7 L.
Let's asume the gas, are at Asbsolute T°, 273K
P. V = n . R . T
3.5 atm . 2L = n . 0.082 . 273K
(3.5 atm . 2L) / (0.082 . 273K) = 0.313 moles
(2.8 atm . 1.5L) / (0.082 . 273K) = 0.188 moles
Total moles = 0.313 mol + 0.188 mol = 0.501 mol
Let's calcualte the hole pressure
P . 7L = 0.501 moles . 0.082 . 273K
P = (0.501 moles . 0.082 . 273K) / 7L → 1.60 atm