The act of changing something but not being able to change it back
1.5.2
(CST): Computer-Scored Unit Test
Question 2 of 25
What is the molality of a solution made by dissolving 6 moles of NaOH in 3 kg
of water?
A. 0.5 mol/kg
B. 3 mol/kg
C. 0.33 mol/kg
D. 2 mol/kg
The molality of a solution : m = 2 mol/kg
Further explanationGiven
6 moles of NaOH
3 kg water
Required
The molality
Solution
Molality shows the number of moles dissolved in every 1000 grams of solvent( 1 kg solvent)
m = n. (1000 / p)
m = Molality
n = number of moles of solute
p = Solvent mass (gram)
Input the value :
m = 6 moles : 3 kg
m = 2 mol/kg
What is the cathode ray? How was the Nature of cathode rays determined?
Answer:
Cathode rays are streams of electrons observed in discharge tubes. In 1897, British physicist J. J. Thomson showed that cathode rays were composed of a previously unknown negatively charged particle, which was later named the electron. Cathode-ray tubes (CRTs) use a focused beam of electrons deflected by electric or magnetic fields to render an image on a screen.
What describes how a liquid flows and diffuses?
A: Fluidity
B: Viscosity
C: Surface tension
D: Condensation
The answer is option is a fluidity
Answer:
A. According to the kinetic-molecular theory of liquids, the particles are not bound together in fixed positions; instead they move about constantly giving them their fluidity
Which statement is true about the speed of light? (2 points) Light travels relatively slowly. Distance in space is measured using the speed of light. Time in space is measured using the speed of light. The speed of light is unknown.
Distance in space is measured using the speed of light.
Answer:
Distance in space is measured using the speed of light.
Explanation:
I took the test
The octane number of gasoline is a measure of octane activity. The octane activity is determined by comparing the engine performance using gasoline and known mixtures of isooctane and n-heptane.
a. True
b. False
Answer:
A. True
Explanation:
The octane number is determined by comparing the characteristics of gasoline to isooctane (2,2,4-trimethylpentane) and heptane. The correct option is option A.
Basically, the higher the octane number, the greater the resistance of the gasoline to knocking.
Rank the effective nuclear charge Z* experienced by a valence electron in each of these atoms:
atom Z* experienced by a valence electron.
An atom of carbon.
An atom of fluorine.
An atom of beryllium.
An atom of boron.
Answer:
The atoms are ranked in decreasing order as follows:
Fluorine ---4
Carbon ----3
Boron ------2
Beryllium --1
Explanation:
Effective nuclear charge (Zeff) is defined as the difference between the actual nuclear charge (the atomic number, Z) and the shielding constant (S).
It is calculated by finding the atomic number and electronic configuration, attributing a shielding value to each electron, adding all the shielding values and using the formula:
Z eff = Z - S
Effective nuclear charges:
An atom of carbon: 3.25
An atom of fluorine: 5.20
An atom of beryllium: 1.95
An atom of boron: 2.60
PLEASE PLEASE HELP!!!
Click an item in the list or group of pictures at the bottom of the problem and, holding the button down, drag it into the
correct position in the answer box. Release your mouse button when the item is place. If you change your mind, drag
the item to the trashcan. Click the trashcan to clear all your answers.
Make a Punnett Square for two smooth seed hybrid pea plants (Ss)
Click once to select an item at the bottom of the problem.
Click again to drop the item in its correct place.
S
SS SS SS S
Forensic scientists encounter few drug investigations in their work.
True
False
Answer:
false
Explanation:
Choose the aqueous solution below with the highest freezing point. These are all solutions of nonvolatile solutes and you should assume ideal van't Hoff factors where applicable.
(i) 0.200 m HOCH2CH2OH
(ii) 0.200 m Ba(NO3)2
(iii) 0.200 m K3PO3
(iv) 0.200 m Ca(CIO4)2
(v) These all have the same freezing point.
Answer:
0.200 m K3PO3
Explanation:
Let us remember that the freezing point depression is obtained from the formula;
ΔTf = Kf m i
Where;
Kf = freezing point constant
m = molality
i = Van't Hoff factor
The Van't Hoff factor has to do with the number of particles in solution. Let us consider the Van't Hoff factor for each specie.
0.200 m HOCH2CH2OH - 1
0.200 m Ba(NO3)2 - 3
0.200 m K3PO3 - 4
0.200 m Ca(CIO4)2 - 3
Hence, 0.200 m K3PO3 has the greatest van't Hoff factor and consequently the greatest freezing point depression.
Fill the plastic cup half full with room-temperature water, and drop in the whole tablet. Use a stopwatch to measure how long it takes the tablet to dissolve completely. Record your observation.
Answer:
it bubbles up and has a chemical reaction also releases co2
Explanation:
Hope it helps <3
HELPPPP PLZ
Using an applied force to move an object in the direction of the force is...
potential energy
the scientific definition of work
none of these
the scientific definition of power
Answer:
the scientific definition of work
Explanation:
In physics, work is defined as the use of force to move an object. For work to be done, the force must be applied in the same direction that the object moves.
I hope it helps! ^^
☁️☁️☁️☁️☁️☁️☁️
One mole of a metallic oxide reacts with one mole of hydrogen to produce two moles of the pure metal
and one mole of water. 5.00 g of the metallic oxide produces 2.32 g of the metal. What is the metallic
oxide? (Use molar masses)
Answer:
Lithium oxide, Li₂O.
Explanation:
Hello!
In this case, according to the given amounts, it is possible to write down the chemical reaction as shown below:
[tex]M_2O+H_2\rightarrow 2M+H_2O[/tex]
Which means that the metallic oxide has the following formula: M₂O. Next, we can set up the following proportional factors according to the chemical reaction:
[tex]5.00gM_2O*\frac{1molM_2O}{(2*X+16)gM_2O}*\frac{2molM}{1molM_2O}*\frac{XgM}{1molM}=2.32gM[/tex]
Thus, we perform the operations in order to obtain:
[tex]\frac{10X}{(2X+16)}=2.32[/tex]
So we solve for x as shown below:
[tex]10X=2.32(2X+16)\\\\10X=4.64X+37.12\\\\X=\frac{37.12}{10-4.64}\\\\X= 6.93g/mol[/tex]
Whose molar mass corresponds to lithium, and therefore, the metallic oxide is lithium oxide, Li₂O.
Best regards!
A diver planning to dive to a depth of 100 ft can choose to breathe air that is a mixture of oxygen, nitrogen, and helium. If the total pressure of the air in the tank is 3040 mm Hg , and the partial pressures of O2 and He are 304 mm Hg and 1520 mm Hg , respectively, what is the partial pressure of N2
Answer:
1216 mmHg = Partial pressure N₂
Explanation:
In a mixture of n gases, the partial pressure of each compound follows the equation:
Total pressure = Partial pressure n₁ + Partial pressure n₂ + Partial pressure n₃ + Partial pressure n₄ + Partial pressure n₅ + ... + Partial pressure nₙ
In a mixture of O₂, He and N₂, the total pressure = 3040mmHg is defined as:
3040 mmHg = Partial pressure O₂ + Partial pressure He + Partial pressure N₂
Replacing:
3040 mmHg = 304 mmHg + 1520 mmHg + Partial pressure N₂
3040 mmHg = 1824 mmHg + Partial pressure N₂
1216 mmHg = Partial pressure N₂
If 50 ml of 0.235 M NaCl solution is diluted to 200.0 ml what is the concentration of the diluted solution
This is a straightforward dilution calculation that can be done using the equation
[tex]M_1V_1=M_2V_2[/tex]
where M₁ and M₂ are the initial and final (or undiluted and diluted) molar concentrations of the solution, respectively, and V₁ and V₂ are the initial and final (or undiluted and diluted) volumes of the solution, respectively.
Here, we have the initial concentration (M₁) and the initial (V₁) and final (V₂) volumes, and we want to find the final concentration (M₂), or the concentration of the solution after dilution. So, we can rearrange our equation to solve for M₂:
[tex]M_2=\frac{M_1V_1}{V_2}.[/tex]
Substituting in our values, we get
[tex]\[M_2=\frac{\left ( 50 \text{ mL} \right )\left ( 0.235 \text{ M} \right )}{\left ( 200.0 \text{ mL} \right )}= 0.05875 \text{ M}\].[/tex]
So the concentration of the diluted solution is 0.05875 M. You can round that value if necessary according to the appropriate number of sig figs. Note that we don't have to convert our volumes from mL to L since their conversion factors would cancel out anyway; what's important is the ratio of the volumes, which would be the same whether they're presented in milliliters or liters.
What is the Chemical formula for Hexacarbon octaphosphide?
Answer:C6P8
Explanation:
How much energy would it take to heat a section of the copper tubing that weighs about 665.0 g, from 15.71 ∘C to 27.09 ∘C ? Copper has a specific heat of 0.3850 (J/g)⋅∘C.
Answer:
2914 J
Explanation:
Step 1: Given data
Mass of the copper tubing (m): 665.0 gInitial temperature: 15.71 °CFinal temperature: 27.09 °CSpecific heat of copper (c): 0.3850 J/g.°CStep 2: Calculate the temperature change
ΔT = 27.09 °C - 15.71 °C = 11.38 °C
Step 3: Calculate the energy required (Q)
We will use the following expression.
Q = c × m × ΔT
Q = 0.3850 J/g.°C × 665.0 g × 11.38 °C
Q = 2914 J
When you remove energy from air or land it makes the temperature
Please don't just take the points. I really need help. I have so many missing assignments please
Answer:
Nuclear reactors do not produce direct carbon dioxide emissions. Unlike fossil fuel-fired power plants, nuclear reactors do not produce air pollution or carbon dioxide during operation. However, processes for mining and refining uranium ore and the production of reactor fuel all require a large amount of energy. Nuclear plants create more jobs than other forms of energy. 7 They create 0.5 jobs for every megawatt hour of electricity produced. This is in comparison to 0.19 jobs in coal, 0.05 jobs in gas-fired plants, and 0.05 in wind power. As a result, new gas-fired power plants were built from 1992 to 2005. an Advantages of nuclear energy Low-cost energy. Although building nuclear power plants has a high initial cost, it's relatively cheap to produce energy from them and they have low operating cost.
Explanation:
A sample of metal has a mass of 24.84 g, and a volume of 4.47 mL. What is the density of this metal?
Answer:
5.56g/ml or 5560kg/m^3
Explanation:
Denisty=mass/volume.
therefore Density= 24.84/4.47.using theSI unit for density is kg/m^3.
I haven’t shifted before I tried like once a few months ago and I keep wanting to shift and last night I had a dream I did is that a sign? I mean where I shifted it was to my friend in Australia so not Hogwarts or Marvel
Scoring Scheme: 3-3-2-1 Part II. You considered the properties of two acid-base indicators, phenolphthalein and methyl orange. Many indicators are weak acids in water and establish the equilibrium: HIn(aq)(Color 1) H2O(l) H3O (aq) In-(aq)(Color 2). Indicators change color depending on whether they are in a protonated (HIn) or unprotonated (In-) form. What is the equilibrium expression for the phenolphthalein indicator in water and what colors are the protonated and unprotonated forms of the indicator
Answer:
Explanation:
Phenolphthalein is a protonated indicator and methyl orange is a basic indicator having hydroxyl ionisable part .
Phenolphthalein can be represented by the following formula
HPh which ionizes in water as follows
HPh + H₂O ⇄ H₃O⁺ + Ph⁻
( colourless ) ( pink )
In acidic solution it is in the form of protonated Hph form which is colourless
In basic medium , it ionises to give H₃O⁺ and unprotonated Ph⁻ whose colour is pink .
Density of water is affected by (select all that apply)
A) Animals that life in the area
B) Salinity (salt concentration)
C) Temperature of water
D) Amount of plants in an area
E) How close the water is to land
What happens during ice wedging
Answer:water expands as it goes from liquid to solid.
Explanation:
The temperature is warm , water works it’s way to to cracks in rock
What is the M, of C3H,COONa? A: Na = 23; C = 12, 0 = 16:
110
87
98
103
Answer: Molecular mass of [tex]CH_3COONa[/tex] is 82 g
Explanation:
Molecular mass (M) is defined as the mass in grams of 1 mole of a substance.
S.I Unit of Molar mass is gram per mole and it is represented as g/mol.
Atomic Mass of Carbon (C) = 12 g
Atomic Mass of hydrogen (H) = 1 g
Atomic Mass of oxygen (O) = 16 g
Atomic Mass of sodium (Na) = 23 g
Molecular mass of [tex]CH_3COONa[/tex] = 12(1)+1(3)+12(1)+16(2)+23(1) = 82 g
What is the overall reaction order for a reaction with the following rate law?
Rate =
k[BrO 3 ][Br][ht]2
Answer:
4
Explanation:
In a rate law, The reaction order is basically the superscript (power) of the concentration of the reaction. It defines the extent to which the rate of the reaction depends on the concentration of the reaction.
In this rate law, the order of the reactants are;
[BrO3] = 1
[Br] = 1
[ht] = 2
The overall reaction order is the sum total of the individual orders. We have;
1 +1 + 2 = 4
At the end of the reaction, an aqueous solution of sodium bisulfite is added to the reaction mixture. The sodium bisulfite destroys the remaining bromine. Also, the fact that the sodium bisulfite is in water helps to further separate the reaction solvent from the product because the solvent is very soluble in water. What is the most important intermolecular force that allows the solvent to dissolve in wate?
Answer:
Polarity.
Explanation:
The most important intermolecular force to allow a solvent to dissolve in water is polarity. This is because water is a polar substance and there is a chemical law that states that there is only solubility between substances of equal polarity. Thus, water is only able to dissolve a polar substance, just like it. In this case, we can say that the equal polarity between the two solvents is the most important for one to be able to dissolve the other.
Choose all the answers that apply.
What does the cardiovascular system do?
transports oxygen and carbon dioxide for the respiratory system
carries nutrients for the digestive system
works with the immune system to fight infection
carries hormones for the endocrine system
sends nerve impulses to the brain and spinal cord
Answer:
All of the above. The CV system transports blood and plasma the do all 4.
How long will it take for the concentration of A to decrease from 0.850 M to 0.205 for the reaction A → Products? (k = 0.0882 M⁻¹s⁻¹)
Answer:
16.1 s
Explanation:
The reaction, A → Products, follows first order kinetics.
So,
ln[A] = ln[A]o - kt
Where;
[A] = concentration at time= t
[A]o = initial concentration
k= rate constant
t = time taken
ln(0.205) = ln(0.850) - 0.0882t
ln(0.205) - ln(0.850) = - 0.0882t
-1.5847 - (-0.1625) = - 0.0882t
-1.5847 + 0.1625 = - 0.0882t
-1.4222 = - 0.0882t
t = -1.4222/- 0.0882
t = 16.1 s
Based on first order kinetics, the time taken for the concentration of A to decrease from 0.850 M to 0.205 M is 16.1 seconds.
What is order of a reaction?The order of a reaction refers to the relationship between the rate of a reaction and the the concentration of each reactant.
For a first-order reaction, the rate is dependent on the concentration of a single species.
The reaction, A → Products is a first order reaction.
Therefore, using the first order kinetics equation
ln[A] = ln[A]° - kt
Where;
[A] = concentration at time= t[A]° = initial concentrationk= rate constantt = time takenSubstituting the values:
ln(0.205) = ln(0.850) - 0.0882t
ln(0.205) - ln(0.850) = - 0.0882t
-1.5847 - (-0.1625) = - 0.0882t
-1.5847 + 0.1625 = - 0.0882t
-1.4222 = - 0.0882t
t = -1.4222/- 0.0882
t = 16.1 s
Therefore, the time taken for the concentration of A to decrease from 0.850 M to 0.205 M is 16.1 seconds.
Learn more about order of reaction at: https://brainly.com/question/7694417
Based on the equation below, how many grams of nitrogen gas will be produced from the decomposition of one mole of sodium aside? Use a molar mass of 28.0 grams for nitrogen gas.
Mass of Nitrogen= 42 grams
Further explanationGiven
one mole of Sodium azide
Required
mass of Nitrogen
Solution
Reaction
The decomposition of one mol of sodium azide :
2 N a N 3 ( s ) → 2Na ( s ) + 3 N2 ( g )
From the equation, the mol ratio of N a N 3 ( s ) : N2 ( g ) = 2 : 3, so mol N2 :
= 3/2 x mol N a N 3
= 3/2 x 1
= 1.5 moles
Mass of Nitrogen
= mol x molar mass
= 1.5 x 28 g/mol
= 42 grams