Answer:
A precipitate is a solid that forms in a liquid when a chemical reaction takes place.
in writing a chemical equation that produces hydrogen gas, the correct representation of hydrogen gas is
a.H
b.2H
c.H2
d.OH
Answer:
h2
Explanation:
Give the ratio that balances out the following equation: ___Cr + ___Pb(NO3)4 ---> ___ Cr(NO3)3 + ____ Pb
Answer: Ratio : 4, 3, 4, 3 are the answers.
Explanation:
Mercury: Mineral or Not Mineral? Mineral Not Mineral
Answer:
not a mineral but is a “mineraloid
Explanation:
not mineral
Explanation: its an element but it is not a mineral
A 1 liter solution contains 0.383 M hydrofluoric acid and 0.510 M potassium fluoride.
Addition of 0.096 moles of calcium hydroxide will:
(Assume that the volume does not change upon the addition of calcium hydroxide.)
Raise the pH slightly
Lower the pH slightly
Raise the pH by several units
Lower the pH by several units
Not change the pH
Exceed the buffer capacity
Answer:
Lower the pH slightly
Explanation:
The mixture of HF, hydrofluoric acid and KF, potassium fluoride produce a buffer that is defined for the equilibrium:
HF(aq) → H⁺(aq) + F⁻(aq)
The buffer can maintain the pH of a solution despite the addition of strong bases or acids.
The reaction of HF with Ca(OH)2 is:
2HF + Ca(OH)2 → 2H2O + CaF2
That means the calcium hydroxide is decreasing the concentration of HF. Based on the equilibrium, the H+ and F- ions will decrease in order to produce more HF. As H+ is decreasing due the equilibrium and not for the addition of a strong base, the pH is decreasing slightly.
Suppose the available nutrients in the soil of an ecosystem decrease. Over time, which adaptation is MOST LIKELY to evolve among the plants that survive there?
Answer:
Root system will become larger or extend farther
Explanation:
If nutrient in soil decrease, the plant's roots system will likely become larger and extend out deeper and farther to get all the nutrients it possibly can
The exact mechanism of this reaction is a little complicated, as it involves the copper ions. However, the process involves the formation of small amounts of bromine in situ. Draw the mechanism of the bromination of 4-tert-butyl phenol with Br2. -g
Answer:
see picture below
Explanation:
The mechanism is in the following picture.
In the first step, the lone pair of oxygen (from the OH) as it's a strong activating group in the molecule, will go to the ring. This will cause that the double bond of the ring of the ortho position, attacks as nucleophyle to the Br2, causing the breaking of the bond.
In the second step, the bromine ion substract the hydrogen from the ortho position, and then, by resonance, the pair of electrons returns to the oxygen of the phenol.
1. How many grams of water are in a cup containing
0.1 moles of H2O?
Answer:
Explanation:
fdcdf
Magnesium hydroxide and sodium hydroxide are both strong bases. The pH of a saturated solution of sodium hydroxide is greater than 14. The pH of a saturated
solution of magnesium hydroxide is about 10.2. Why do the solutions have different pH values?
Answer: Solubility of NaOH is greater and there are more OH- ions in solution.
Explanation: Reactions : NaOH (s) ⇒ Na+ (aq) + OH- (aq)
Mg(OH)2 (s) ⇒ Mg2+ (aq) + 2 OH-(aq)
Although in same amount of moles, Mg(OH)2 produces
two (OH-)-ions in water solution, solubility of Mq(OH)2 is smaller.
Concentration [OH-]ions is smaller in saturated water solution
of Mg(OH)2
If an acid has a pH of 2, what is its [H^ + ] ?
Show work
Check G the answer is up theree
Octane (C8H18) is found in gasoline. It is burned for fuel in a combustion
reaction. The unbalanced combustion reaction for octane is shown below.
C8h18+ O2 → C02 + H2O + heat
When the reaction is balanced, how many carbon dioxide molecules are
produced for every octane molecule burned?
Answer:
Explanation:
It's 8
mrs tuckers class is doing an experiment they fill up a cup with ice water they measure the temperature of both the water and the classroom after one hour . what will mrs tucker observe about the temperature of ice water after one hour
A. The temperature will increase
B. The temperature Will remain the same
C. The temperature will decrease greatly
D. The temperature Will decrease slightly
Answer:
Ofc D. bc if the temp decreases, that means it is getting colder u dummy! But if it increases, it is getting warmer.
Explanation:
I got it right on USATestprep for using common sense, mark me the brainliest.
The following are reactants in the chemical reaction shown below.
6CO2 + 6H2O --> C6H12O6 + 6O2
A. CO2 and H2O
B. C6H12O6 and O2
C. H2O and O2
D. CO2 and C6H12O6
Answer:
A
Explanation:
Reactants are on the right side of the chemical reaction
Question 5 (5 points)
Complete the following sentences:
a)
is the least reactive alkall metal.
b)
is the most reactive alkali metal.
is the least reactive alkaline earth metal.
d)
is the most reactive alkaline earth metal.
e)
is the most reactive halogen
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Question 6.12
How many moles of sodium hydroxide would have to be added to 150 mL of a 0.483 M acetic acid solution, in order to prepare a buffer with a pH of 4.480
Answer:
0.068 moles of sodium hydroxide would have to be added to 150 mL of a 0.483 M acetic acid solution
Explanation:
As we know
pH = pKa + log [salt]/[acid]
4.480= 4.74 + log [salt]/[acid]
log [salt]/[]acid] = -0.06
[salt]/[acid] = 0.87
moles acid = 0.150 L x 0.483 mol/L = 0.07245 moles acid
x/0.07245-x = 0.87
X- 0.07245 X = 0.87 *0.07245
X = 0.068 moles
What do greenhouse gases do on Earth?
Answer:
It holds heat from the sun close to Earth.
Explanation:
Hope this helps and have a great day. :)
Isoniazid is used in the treatment of tuberculosis and multiple sclerosis. Identify each lone pair as either localized or delocalized. Justify your answer in each case.
Answer:
Please find the complete question and its solution in the attached file:
Explanation:
A sample of aluminum requires 341 J of energy to raise the temperature from 18.0ºC to 55.0ºC. Calculate the mass of the aluminum sample.
Answer:
10.22g
Explanation:
Using the formula as follows:
Q = m × c × ∆T
Where;
Q = amount of heat required (J)
m = mass of substance (g)
c = specific heat of substance (J/g°C)
∆T = change in temperature (°C)
According to the information given in this question;
Q = 341J
m = ?
∆T = 55.0ºC - 18.0ºC = 37°C
c of aluminum = 0.902J/g°C
Using Q = m × c × ∆T
341 = m × 0.902 × 37
341 = 33.374m
m = 341 ÷ 33.374
m = 10.22g
At a certain temperature the vapor pressure of pure benzene is measured to be . Suppose a solution is prepared by mixing of benzene and of heptane . Calculate the partial pressure of benzene vapor above this solution. Round your answer to significant digits.
Answer:
P(C₆H₆) = 0.2961 atm
Explanation:
I found an exercise pretty similar to this, so i'm gonna use the data of this exercise to show you how to do it, and then, replace your data in the procedure so you can have an accurate result:
"At a certain temperature the vapor pressure of pure benzene (C6H6) is measured to be 0.63 atm. Suppose a solution is prepared by mixing 79.2 g of benzene and 115. g of heptane (C7H16) Calculate the partial pressure of benzene vapor above this solution. Round your answer to 2 significant digits. Note for advanced students: you may assume the solution is ideal".
Now, according to the data, we want partial pressure of benzene, so we need to use Raoul's law which is:
P = Xₐ * P° (1)
Where:
P: Partial pressure
Xₐ: molar fraction
P°: Vapour pressure
We only have the vapour pressure of benzene in the mixture. We need to determine the molar fraction first. To do this, we need the moles of each compound in the mixture.
To get the moles: n = m / MM
To get the molar mass of benzene (C₆H₆) and heptane (C₇H₁₆), we need the atomic weights of Carbon and hydrogen, which are 12 g/mol and 1 g/mol:
MM(C₆H₆) = (12*6) + (6*1) = 78 g/mol
MM(C₇H₁₆) = (7*12) + (16*1) = 100 g/mol
Let's determine the moles of each compound:
moles (C₆H₆) = 79.2 / 78 = 1.02 moles
moles (C₇H₁₆) = 115 / 100 = 1.15 moles
moles in solution = 1.02 + 1.15 = 2.17 moles
To get the molar fractions, we use the following expression:
Xₐ = moles(C₆H₆) / moles in solution
Xₐ = 1.02 / 2.17 = 0.47
Finally, the partial pressure is:
P(C₆H₆) = 0.47 * 0.63
P(C₆H₆) = 0.2961 atmHope this helps
How do the equilibrium concentrations of the reactants compare to the equilibrium concentrations of the product?
Answer: It depends equilibrium constant K
Explanation: You need to to have reaction formula.
If K >> 1 then concentrations of products are much bigger than
concentrations of reactants. If K < < 1, concentration of products is small.
In which phase of wound healing is fibrin most involved?
Answer:
Finally, coagulation occurs and reinforces the platelet plug with threads of fibrin which are like a molecular binding agent. The hemostasis stage of wound healing happens very quickly.
Explanation:
Hope it helps u
FOLLOW MY ACCOUNT PLS PLS
give an example of a primary income from the rest of the world
Answer:
(1) Income Associated with the Production Process
(a) Compensation of employees
(b) Taxes and subsidies on products and
production .
(2) Property Income
(a) Investment income:
• Dividends and withdrawals from income of
quasi-corporations
• Reinvested earnings
• Interest
(b) Rent .
I hope this is correct :-)
A student determines that the theoretical yield of CaCO3, from a precipitation reaction is 21.5 grams
However, this student only recovers 19.9 grams of precipitate through filtration of the solution.
What would be this student's percent yield?
A. 92.6%
B. 0.93%
C. 108%
D. 85.6%
Answer:
92.6
Explanation:
15. Objects can have kinetic energy, potential energy, or both. Energy can be in the form of motion. Energy can
also be stored by objects in various ways, including position, chemical bonds, or physical state.
Which statement is true? And why?
a. An object’s mass has no effect on its potential energy.
b. Potential energy is converted to kinetic energy as a stationary object begins to move.
c. Kinetic energy is converted to potential energy as a stationary object begins to move.
d. A stretched rubber band stores no energy.
Answer: b because Potential energy is converted to kinetic energy as a stationary object begins to move.
Explanation:
What number should be written in front of Na to balance the equation?
Na + MgCl2 → NaCl + Mg
1
2
3
4
In order to balance the chemical equation, the coefficient of Na should be 2.
1.. A saturatedsolutionA.contains more solute thansolvent.B.contains more solvent thansolute.C.contains equal moles of solute andsolvent.D.contains the maximum amount of solute that will dissolve in that solvent at that temperature.E.contains a solvent with only sigma bonds and no pi bonds (i.e. only single bonds, with no doubleor triplebonds).
Answer:
D. contains the maximum amount of solute that will dissolve in that solvent at that temperature.
Explanation:
Solubility is a term used to describe how readily a substance can be dissolved in a solvent to form a solution. Thus, a substance is said to be soluble if it dissolves completely in a solvent and insoluble if it doesn't dissolve or only dissolves partially.
For example, sodium chloride (NaCl) when mixed with water dissociates into sodium and chloride ions. Thus, salt (sodium chloride) is said to be soluble because it dissolves completely in water.
Hence, a compound that dissolves in water to produce an aqueous solution is said to be soluble in water. Also, the solute of an aqueous solution that conducts electricity is called an electrolyte.
In Chemistry, dissolution can be defined as the process of dissolving or dissociating a solute in solid, liquid or gaseous phase into fragmented particles by a solvent in order to form a solution. For dissolution to occur in solids, the crystalline structure of the substance must be broken up so as to release ions, atoms or molecules to produce a solution. For liquid and gases, the substance to be dissolved must form a non-covalent bond with the solvent to produce a solution.
Generally, a saturated solution contains the maximum amount of solute that will dissolve in that solvent at that temperature.
What compound(s) does pure water contain?
Given 23 g of potassium nitrate per 25 g of water, what temperature should create a saturated solution?
Answer:
At about 51 °C
Explanation:
Hello there!
In this case, according to the attached solubility chart of potassium nitrate, our first step for this problem is to calculate the grams of this solute in 100 g given that 23 g are soluble in 25 g of water:
[tex]\frac{23g}{25g}=\frac{x}{100g}\\\\x= \frac{23g*100g}{25g}=92g[/tex]
Thus, such solubility of 92 g in 100 g of water is exhibited at about 51 °C.
Regards!
I need guidance on this question
Answer:
(C) NO2 has covalent bonds.
A community located downwind from a coal-fired power plant has seen a recent increase in the number of dead and dying trees. A so scientist measured values for the following parameters before and after the trees died off. Which of the following oil data should be used to determine if the coalfired power plant emiations were the cause of the damage to the trees
a. Moisture content and water retention
b. Parent material composition
c. Pesticide and herbicide residue levels
d. Calcium and aluminum levels
Answer:
Option D, Calcium and Aluminum levels
Explanation:
The coal fired power plant releases huge amount of particulate and gaseous emissions such as mercury, sulphur dioxide, nitrogen oxide etc. When there is rain, these gaseous and particulate matter comes to the ground along with rain water and pollute the soil. There are also chances of acid rain due to the presence of sulphur dioxide. Polluted soil and acid rain negatively impact the growth of the plants and causes leaching of Aluminium thereby decreasing the availability of calcium for the plants. Thus, the trees die. Hence, if the amount of Aluminium and Calcium in soil is determined, one can easily deduce the cause of death of trees.
Hence, option D is correct
Food Science is the study of the physical, biological, and chemical makeup of food; the
causes of food deterioration; and the concepts ulderlying food processing.
True
False