Answer:
4.02g of Na2CO3⸱2H2O must be added completing the volume of the solution to 100mL
Explanation:
A 3%(w/v) solution contains 3g of solute (In this case, Na2CO3) in 100mL of solution.
Assuming we require 100mL of solution we must add 3g of Na2CO3. The reactant that is available is its dihydrate, with molar mass:
106g/mol + 2*MW H2O
106g/mol + 2*18g/mol = 142g/mol
That means the mass of Na2CO3.2H2O that must be added to prepare the solution is:
3g Na2CO3 * (142g/mol Na2CO3.2H2O / 106g/mol Na2CO3) =
4.02g of Na2CO3⸱2H2O must be added completing the volume of the solution to 100mLWhat is the difference between chemical change and physical change
Answer:
In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed.
Describe the three values in a learner-centred curriculum that a teacher can use
to create a pedagogy of care in the classroom.
Answer:
to talk in a way that the class can all understand . help them in thing they are falling . and have a good relashaship.
Explanation:
helphelp help gell help helpp
Which of the following things is not made of wither fermentation?
Cheese
Yogurt
Bread
Peanut butter
Chocolate
If you have 4 molecules of FeCl3 and an unlimited supply of NaOH, how
many molecules of NaCl can you produce given the following balanced
equation?
FeCl3 + 3NaOH --> Fe(OH)3 + 3NaCl
Answer:
12 molecules of NaCl
Explanation:
The term "unlimited supply of NaOH" means that NaOH is the reactant in excess hence FeCl3 is the limiting reactant that controls the amount of product formed.
Thus;
From the balanced reaction equation;
1 molecule of FeCl3 yields 3 molecules of NaCl
Hence;
4 molecules of FeCl3 yields 4 * 3/1 = 12 molecules of NaCl
When a certain nuclide undergoes alpha emission, astatine-217 is produced. What is the identity of the nuclide that underwent decay?
a. actinium-219
b. francium-217
c. francium-221
d. astatine-221
e. actinium-221
Please explain the answer
Answer:
C: francium-221
Explanation:
First of all to get a broader perspective, every isotope of francium usually undergoes decay to form astatine, radium, or radon.
Now, Francium-223 and francium-221 are it's only isotopes that occur in nature.
However, francium-221 is the one that undergoes alpha decay to produce astatine-217.
A generator makes electricity from _____.
chemical reactions
kinetic energy
heat
friction
Share what you have learned about first aid to your family......
please help me with this.
Answer:
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=> First Aid enables you to assist persons who become injured in the event of an accident or emergency situation until help arrives.
[tex] \huge\blue{ \mid{ \underline{ \overline{ \tt Situations :- }} \mid}}[/tex]
=> If an accident happens in the workplace, in your home or in a public space, you can use the help of a first aid kit.
=> In situations such as when someone ingests a harmful substance, suffers from a heart attack, a seizure or stroke, is involved in a motor vehicle accident or is caught in a natural disaster, a person trained and knowledgeable in even the very basics of First Aid can be of extreme importance in assisting the injured person(s) until emergency responders arrive.
The breakdown of proteins produces
A. Carbon dioxide
B. Urea
C. Water
Answer:
B.Urea
Explanation:
When an amino acid is broken down, the nitrogen it contains is converted into urea by the liver which then is excreted via the kidneys.
Answer:
urea
Explanation:
when u eat proteins the body breaks them down into amino acids . Ammonia is produced from leftover amino acids and it must be removed from the body. the liver produces many chemicals (enzymes) that change ammonia into a form called ureas
The shadow of a groundhog ( or anything else ) is determined what?
The size, length, and height of the figure are the main factors which determine the shadow of a organism.
The size, length, and height of the figure are the main factors which determine the shadow of a organism.
What is a shadow?A shadow is a dark area where light from a light source is blocked by an opaque object. It occupies all of the three-dimensional volume behind an object with light in front of it. The cross section of a shadow is a two-dimensional silhouette, or a reverse projection of the object blocking the light.
A point source of light casts only a simple shadow, called an "umbra". For a non-point or "extended" source of light, the shadow is divided into the umbra, penumbra, and antumbra. The wider the light source, the more blurred the shadow becomes. If two penumbras overlap, the shadows appear to attract and merge. This is known as the shadow blister effect.
Learn more about shadow,here:
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If 6.75 g of NaOH are dissolved in 50.00 g of water and the temperature increases
from 20.5°C to 47.8 °C.
a. Is this an example of an endothermic or exothermic reaction?
b. What is the q for the reaction? (Remember since the NaOH dissolves in water add the
masses to get the m)
C. How many moles of NaOH are dissolved?
d. What is the AH for the reaction?
Answer: THE STANDARD HEAT OF SOLUTION OF SODIUM HYDROXIDE IN WATER IS -7.68 KJ PER MOLE.
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Answer:
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pls give brainlyest
Explanation:
200 IQ intellectual right here ^^
What is the mass in grams of 7.5 mol of C8H18?
Answer:
[tex]\boxed {\boxed {\sf 856.74 \ g \ C_8H _{18}}}[/tex]
Explanation:
To convert from grams to moles, the molar mass is used. These values tells us the grams in 1 mole of a substance. They can be found on the Periodic Table (they are equivalent to the atomic masses, but the units are grams per mole).
We are given the compound C₈H₁₈. Look up the molar masses of the individual elements.
Carbon (C): 12.011 g/mol Hydrogen (H): 1.008 g/molNotice there are subscripts that tell us the number of atoms of each element. We must multiply the molar masses by the subscripts.
C₈: 8(12.011 g/mol)=96.088 g/mol H₁₈: 18(1.008 g/mol)=18.144 g/molAdd these 2 values together to find the molar mass of the whole compound.
C₈H₁₈: 96.088 g/mol +18.144 g/mol=114.232 g/molUse this number as a ratio.
[tex]\frac{ 114.232 \ g \ C_8H_{18}}{1 \ mol \ C_8H_{18}}[/tex]
Multiply by the given number of moles: 7.5
[tex]7.5 \ mol \ C_8H_{18}*\frac{ 114.232 \ g \ C_8H_{18}}{1 \ mol \ C_8H_{18}}[/tex]
The moles of C₈H₁₈ will cancel each other out.
[tex]7.5 *\frac{ 114.232 \ g \ C_8H_{18}}{1}[/tex]
[tex]7.5 *{ 114.232 \ g \ C_8H_{18}}[/tex]
[tex]856.74 \ g \ C_8H _{18}[/tex]
7.5 moles of C₈H₁₈ is equal to 856.74 grams of C₈H₁₈
In both industry and research there are often times when one particular component of a mixture needs to be separated from a solution. Maybe it is a rare metal that is dissolved in a mixture of minerals. Maybe it is a particular protein from lysed plant cells. If the desired component is volatile, distillation could be used. But if the goal is to separate ions in solution, fractional precipitation is preferred.
a. True
b. False
Answer:
a. True
Explanation:
Distillation process is a process that is used to separate the components or the substances from the liquid mixtures by using selectively boiling and condensation.
While fractional precipitation is a process which separates the ions from solution based on the different solubilities.
Therefore, the answer is true.
Introduction: Reaction rates are also influenced by surface area and concentration. The surface area of a solid is a measure of how much of the solid is exposed to other substances. The concentration of a substance is a measure of how many molecules of that substance are present in a given volume. Question: How do surface area and concentration affect reaction rates
Answer:
See explanation
Explanation:
Surface area has to do with the number of solid particles that are exposed at a given time and is capable of colliding with other reactant particles. When more surface area is exposed for reaction, then it means that more particles are likely to collide with each other leading to faster chemical reaction rates. When few particles are exposed for reaction (low surface area) then less collisions occur and the rate of reaction is decreased.
Similarly, concentration refers to the amount of substance present. The greater the amount of substance present, the greater the likelihood of collision between particles and the greater the rate of reaction and vice versa.
When H2(g) reacts with F2(g) to form HF(g) , 542 kJ of energy are evolved for each mole of H2(g) that reacts. Write a balanced thermochemical equation for the reaction with an energy term in kJ as part of the equation.
Answer:
H₂(g) + F₂(g) ⇒ 2 HF(g) ΔH°rxn = -542 kJ
Explanation:
Let's consider the unbalanced equation that occcurs when H₂(g) reacts with F₂(g) to form HF(g).
H₂(g) + F₂(g) ⇒ HF(g)
In order to get the balanced equation, we will multiply HF(g) by 2.
H₂(g) + F₂(g) ⇒ 2 HF(g)
To convert a balanced equation into a thermochemical equation, we need to add the standard enthaply of the reaction, considering that 542 kJ of energy are evolved for each mole of H₂(g) and there is 1 mole of H₂(g) in the balanced equation. By convention, when energy is released, it takes a negative sign. The thermochemical equation is:
H₂(g) + F₂(g) ⇒ 2 HF(g) ΔH°rxn = -542 kJ
The direct transfer of thermal energy between particles of
matter that are touching is called
Answer:
conduction
Explanation:
How does an electric field change and influence its surroundings?
Answer:
The electric force acts over the distance separating the two objects. ... The space surrounding a charged object is affected by the presence of the charge; an electric field is established in that space. A charged object creates an electric field - an alteration of the space or field in the region that surrounds it.
Explanation:
how many moles of an NH3 can be produced from 2.82 moles of nitrogen in the following reaction:
Pls help ASAP it’s timing meeee!!!!!
What mass of NaCrO2 can be obtained from the reaction of 7.40g Cr(OH)3 with 7.60g NaOH in the following reaction: CrOH3+NaOH==>NaCrO2+2H2O
Explanation:
7.60 g of NaOH = 7.6/40 = 0.19 moles.
Reaction is 1:1 so NaOH in excess and Cr(OH)3 is limiting reactant.
You will get maximum of 0.0718 moles of NaCrO2 which is 0.0718*107 = 7.69 g
The mass of NaCrO₂ that can be obtained from the reaction is 14.92 grams.
To determine the mass of NaCrO₂ obtained, we need to calculate the molar mass and stoichiometry of the reaction.
Calculate the molar mass of Cr(OH)₃ and NaOH:
Molar mass of Cr(OH)₃ = 52.00 g/mol (chromium: 52.00 g/mol, oxygen: 16.00 g/mol, hydrogen: 1.01 g/mol)
Molar mass of NaOH = 39.99 g/mol (sodium: 22.99 g/mol, oxygen: 16.00 g/mol, hydrogen: 1.01 g/mol)
Determine the limiting reagent:
Convert the mass of Cr(OH)₃ to moles: 7.40 g Cr(OH)₃ * (1 mol / 52.00 g) = 0.1423 mol Cr(OH)₃
Convert the mass of NaOH to moles: 7.60 g NaOH * (1 mol / 39.99 g) = 0.190 mol NaOH
The stoichiometry of the reaction tells us that 1 mol of Cr(OH)₃ reacts with 1 mol of NaOH to produce 1 mol of NaCrO₂.
Compare the moles of Cr(OH)₃ and NaOH to determine the limiting reagent:
Cr(OH)3: 0.1423 mol
NaOH: 0.190 mol
Since Cr(OH)₃ has fewer moles, it is the limiting reagent.
Calculate the mass of NaCrO₂ produced:
The molar mass of NaCrO₂ is 105.00 g/mol (sodium: 22.99 g/mol, chromium: 52.00 g/mol, oxygen: 16.00 g/mol)
The stoichiometry tells us that 1 mol of Cr(OH)₃ produces 1 mol of NaCrO₂.
Therefore, the mass of NaCrO₂ obtained is:
0.1423 mol Cr(OH)₃ * (105.00 g NaCrO₂ / 1 mol Cr(OH)₃) = 14.92 g NaCrO₂
Thus, the mass of NaCrO₂ that can be obtained from the reaction is 14.92 grams.
To learn more about stoichiometry here
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It takes 53.0 J to raise the temperature of an 11.0 g piece of unknown metal from 13.0∘C to 24.3 ∘C. What is the specific heat for the metal?
Answer:
51 = ( 8.2/1000)Kg ×S (11.5)
51×1000= 8.2 (11.5)S
S = 51000/94.3
S = 540.8 J/kg K
Explanation:
Si tengo 56 gramos de amoniaco gaseoso (NH3) ¿Cuántos moles y moléculas (entidades elementales) podré obtener?
Answer: 56 grams of gaseous ammonia (NH3), has 3.28 moles and [tex]19.80 \times 10^{23}[/tex] molecules.
Explanation:
Given: mass of [tex]NH_3[/tex] = 56 g
Molar mass of [tex]NH_3[/tex] is 17.03 g/mol.
As moles of a substance are its mass divided by the molar mass. Therefore, moles of [tex]NH_3[/tex] are calculated as follows.
[tex]No. of moles = \frac{mass}{molar mass}\\= \frac{56 g}{17.03 g/mol}\\= 3.28 mol[/tex]
According to the mole concept, 1 mole of every substance contains [tex]6.022 \times 10^{23}[/tex] molecules. Hence, number of molecules present in 3.28 moles of [tex]NH_3[/tex] are calculated as follows.
[tex]No. of molecules = no. of moles \times 6.022 \times 10^{23}\\= 3.28 mol \times 6.022 \times 10^{23}\\= 19.80 \times 10^{23}[/tex]
Therefore, we can conclude that 56 grams of gaseous ammonia (NH3), has 3.28 moles and [tex]19.80 \times 10^{23}[/tex] molecules.
I need to know what the question is asking please help
Answer: What events create the heaviest elements?
I would Select:
Neutron Star Collissions
Supernova
You and several novice researchers decide to set up some experiments in an attempt to explain why potassium reacts with oxygen to form a superoxide. One of your team members proposes that potassium's capacity to form a superoxide compound is related to a low value for the first ionization energy. If you wanted to validate this hypothesis, indicate two metals other than potassium (in order of increasing atomic number) that you could examine to see if they also form superoxides when reacted with oxygen gas.
Required:
Express your answers as chemical symbols separated by a comma.
Answer:
Rubidium and cesium
Explanation:
It is noteworthy to say here that larger cations have more stable superoxides. This goes a long way to show that large cations are stabilized by large cations.
Let us consider the main point of the question. We are told in the question that the reason why potassium reacts with oxygen to form a superoxide is because of its low value of first ionization energy.
The implication of this is that, the other two metals that can be examined to prove this point must have lower first ionization energy than potassium. Potassium has a first ionization energy of 419 KJmol-1, rubidium has a first ionization energy of 403 KJ mol-1 and ceasium has a first ionization energy of 376 KJmol-1.
Hence, if we want to validate the hypothesis that potassium's capacity to form a superoxide compound is related to a low value for the first ionization energy, we must also consider the elements rubidium and cesium whose first ionization energies are lower than that of potassium.
What unit should you think of when using coefficients?
Answer:
Far as I know coefficients are unitless. sorry if this don't help ;)
Consider the following data on some weak acids and weak bases
acid
Ka
name formula
acetic acid
HCH3CO2
1.8 x10−5
hydrocyanic acid
HCN
4.9 x 10−10
base
Kb
name formula
pyridine
C5H5N
1.7 x 10−9
ammonia
NH3
1.8 x 10−5
Use this data to rank the following solutions in order of increasing pH. In other words, select a '1' next to the solution that will have the lowest pH, a '2' next to the solution that will have the next lowest pH, and so on.
a. 0.1M NaCH3CO2
b. 0.1M NH4Br
c. 0.1M NaBr
d. 0.1M KCN
Answer:
b < c < a < d
Explanation:
The weak acid with the lowest pKa will be the most acidic. In the other way, the conjugate base which the acid is weak will be strong.
The weak base with the lowest pKb will be the most basic. And the conjugate base of the weak base will be a strong acid.
Ka Acetic acid = 1.8x10-5
Ka HCN = 1.9x10-10
Kb pyridine = 1.7x10-9
Kb NH3 = 1.8x10-5
NH4Br is the conjugate base of a weak base. That means is a strong acid.
NH4Br has the lowest pH
NaBr is the conjugate base of a strong acid, HBr. That means NaBr is neutral
The most basic between the conjugate base of the acetic acid, NaCH3CO2 and KCN is KCN because the acetic acid is the stronger acid regard to HCN.
The rank is:
NH4Br < NaBr < NaCH3CO2 < KCN
b < c < a < dWhat is the Same about carbohydrates, proteins , and fats ?
Answer:
The main similarity between carbohydrates, proteins and fats is that they are all used for energy.
Explanation:
I hope this helps, have a blessed day.
What is the mass of 7.004 x 1023 molecules of calcium chloride?
Answer:
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In the graph above, what is the relationship between volume and temperature? Does this data support Charles' Law?
Hint: is it a direct or inverse relationship? How does volume change with temperature changes?
Answer:
No the graph does not support Charles' Law. Both volume and temperature increase so it would be a direct relationship.
Explanation:
How much does REAL carbon fiber cost ? lets say as big as a piece of paper
Answer:
Today, the average total production cost of “standard modulus” carbon fiber is in the range of $7-9 per pound.