Answer:
Alkali metals have 1 valence electron on their outer shell. They are more stable when they have 8 valence electrons, so they want to lose that valence electron. They do this by bonding with other elements. When they lose their 1 valence electron, they have a full octet and are therefore stable.:
Which statement best describes how an existing theory is often affected by the development of new technology?
An existing theory is thrown out and replaced with a completely new theory based on the new observations.
An existing theory is modified so that it can explain both the old and new observations.
An existing theory remains the same because a theory is a proven fact that is always true.
An existing theory is kept unchanged while a new theory is developed to explain the new observations.
Answer: An existing theory is modified so that it can explain both the old and new observations.
Explanation:
Answer:
The correct anwser would be B
Explanation:
72 drops were 1ml for stearic acid
the container was 8.5 cm wide and filled with hexane
Trial 1 was 20 drops
Trial 2 was 21
trial 3 was 16
The concentration of steric solution in hexane was :1.64*10^-4 g/ml
Area of single molecule of steric acid is: 0.21 mn^2
Molar mass of steric acid is: 284 g/mol
-What is the moles of stearic acid used?
-What is the number of stearic acid used to make the lens?
-how many molecules of stearic acid would there be if its it was 1 mole of stearic acid on that lense?
CaseAnswer:
-Mole of stearic acid used = 1.3*10^-3 mol
-Molecules of stearic acid there would be in 1 mole of stearic acid = 7.994*10^20 molecules
Explanation:
Know information from the problem are:
Mass concentration of C18H32O2 = 1.6x10^-4 g/ml, Molar mass of C18H32O2 = 284 g/mol.
Unit factor from drops to ml is 72 drops = 1ml. Therefore, for every drop, n, given, there would be n drops (1ml/ 72drops). The problem tells that stearic acid was added to hexane and that the addition process was done three-time with different amounts of drops. Think of this as releasing a substance from a burette during titration. If we convert the drops into millimeters, we would have 20 drops (1ml/72drops)= 0.28 ml, 21 drops (1ml/72drops)= 0.29 ml, and 16 drops (1ml/72drops)= 0.22 ml. [We need these volumes to determine the mass of stearic acid from mass concentration given.]
Unknown informations are:
V (volume in ml) =?
The mole of stearic acid used =?
Strategy
To calculate the mole of stearic acid used, we need the mass of stearic acid from the mass concentration. To get this we need a volume. Notice that those volumes (drops) are not the same ( it is safe to say that there is an error in the readings, as they were done independently). Therefore, we would find two or three values whose difference is smaller ( there is a little error). Subtract the smaller number from the larger number till you get a smaller difference ( do this for all three values).
The set of numbers with the smallest difference is 0.29 - 0.28=0.014, our concordant value.
Solutions
Now we us this set of numbers, 0.29-0.28, to determine an average volume :
V = (0.29-0.28)/2 (ml)
V= 0.285 ml
Now we can calculate the mass of stearic acid from the mass concentration:
m = C*V; m is the mass, C is the concentration in g/ ml, and V is the volume in ml.
m = (1.64*10^-4 g/ml)*(0.285 ml)
m = 4.674*10^-5 g
The mole of stearic acid used:
n = m/MM l; n is the mole of stearic acid, m is the mass of stearic acid, and MM is the molar mass of stearic acid.
n = 4.674*10^-5 g (284 g/mol)
n = 1.3274*10^-3
How many molecules of stearic acid would there be if it was 1 mol of stearic acid?
1 mol = 6.02214*10^23 molecule
Therefore, a conversion fraction would be:
6.02214*10^23 molecule/ 1 mol
Solution
Molecules of stearic acid in 1 mol =
1.3274*10^-3 mol (6.02214*10^23 molecule/ 1 mol)
= 7.994*10^20 molecules in 1 mol of C18H16O2
The velocity of an object consists of its speed and..
A. Average speed
B. Distance
C. Displacement
D. Direction
Answer:
direction
Explanation:
sand is a particulate in nature
Answer:
[tex]\color{Blue}\huge\boxed{Answer} [/tex]
Sand is a granular material composed of finely divided rock and mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt.
why is the sky black in space
Answer:Since there is virtually nothing in space to scatter or re-radiate the light to our eye, we see no part of the light and the sky appears to be black.
Explanation:
who is the first person to discover the periodic table
I need help with science: Which picture best shows a loud, low-pitched sound?
Image A shows a loud and low-pitched sound.
What is the frequency?
The term frequency refers to the number of waves that pass a fixed point in unit time.
High pitched sound is of higher frequency because they make the air molecules vibrate much faster than low-pitched sound. Due to their high frequency, their wavelength is shorter (Remember wavelength and frequency are inversely proportional). Vice versa is true to the low-pitched sound. They vibrate air molecules slower than high-pitched sound. Their wavelength is longer and frequency smaller.
Hence, option A is the correct answer.
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Five liters of air at -35°C is warmed to 89°C. What is the new volume if the pressure remains constant
Answer:
7.61 liters
Explanation:
From the question,
Applying Charles law formula,
V₁/T₁ = V₂/T₂...................... Equation 1
Where P₁ = initial volume of of air, V₂ = Final volume of air, T₁ = Initial Temperature of air, T₂ = Final Temperature of air.
make V₂ the subject of the equation
V₂ = (V₁×T₂)/T₁............... Equation 2
Given: V₁ = 5 liters, T₁ -35 °C = (-35+273) K = 238 K, T₂ = 89°C = (89+273) K = 362 K
Substitute these values into equation 2
V₂ = (5×362)238
V₂ = 1810/238
V₂ = 7.61 liters
ADD NOTE
QUESTION GUIDE EXIT TES
3. A sample of 0.0400 mol potassium hydroxide, KOH was dissolved in water to yield 20.0 ml of
solution. What is the molarity of the solution?
Answer:
2.00 M KOH
Explanation:
Divide moles by volume and make sure your volume is in LITERS, not mL.
0.0400 mol KOH / 0.0200 L = 2.00 M KOH
A sample of 0.0400 mol potassium hydroxide, KOH was dissolved in water to yield 20.0 ml of solution. The molarity of the solution is 2.00 M KOH.
What is molarity?Molarity is the measure of the concentration of any solute in per unit volume of the solution.
[tex]M = \dfrac{n}{V}[/tex]
Given, the 0.0400 mol potassium hydroxide
20.0 ml volume
Putting the values in the equation
[tex]\dfrac{0.0400 mol }{ 0.0200 ml} = 2 M[/tex]
Thus, the molarity of the solution is 2.00 M KOH.
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How does sunlight affect seasons?
Answer:
Seasons are caused by the Earth’s revolution around the Sun, as well as the tilt of the Earth on its axis. The hemisphere receiving the most direct sunlight experiences spring and summer, while the other experiences autumn and winter. During the warmer months, the Sun is higher in the sky, stays above the horizon for longer, and its rays are more direct.
A manufacturer selected a metal to use in producing a lightweight button for clothing. A metal that has a density of 2.71 g/cm3 was selected. Which of the metals was selected?
Answer:
d
Explanation:
Pt2 science......
Select correct answer ♡!
Atmospheric pressure on the peak of Mt. Everest can be as low as
0.197 atm, which is why climbers need to bring oxygen tanks for the
last part of the climb. If the climbers carry 10.0 liter tanks with an
internal gas pressure of 40 atm, what will be the volume of the gas
when it is released from the tanks?
acids are and can destroy your skin and bones
Answer:
This is true.
Explanation:
how does the concept of polarity relate to bond formation and molecular shape?
Answer: heyyyooo
The bond polarity for each bond in a BH3 molecule is polar, due to the difference in electronegativities of the B and H atom. The molecular shape is trigonal planar, and the molecule is non-polar - because due to the symmetry of the molecule, the polarities cancel out.
Explanation:
hope this helps!
Pablo wants to enter the science fair. Which question could be answered through scientific investigation?
Answer:
Hello
Explanation:
utd847dcpyc08td0
How much water must be added to 40.0 g of CaCl2 to produce a solution that is 35.0 wt% CaCl2?
The mass of water present in the solution is 21.5 g.
What is concentration?Concentration refers to the amount of solute in a solution. There are various ways of expressing concentration such as;
Molar concentrationMass concentrationPercentage concentrationWe have the following information;
Percent concentration = 35.0 %
mass of solute = 40.0 g
Mass of water = ?
So;
35 = x/40 + x × 100/1
35 = 100x/40 + x
35(40 + x) = 100x
1400 + 35x = 100x
1400 = 100x - 35x
1400 = 65x
x = 1400/65
x = 21.5 g
Hence the mass of water is 21.5 g.
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Waves that we cannot actually see (unlike ripples in water) and that DO NOT need a medium to travel through belong to which category of waves?
Answer:
electromagnetic waves
Explanation:
The waves that do not need a medium to travel through are known as electromagnetic waves.
What are electromagnetic waves?These waves do not need any medium for their propagation or traveling. The waves have different wavelength and energy factors depending upon their rate of propagation. EMR waves travel from the sun to the earth in space.
Examples of electromagnetic waves are Xrays, gamma rays, radio waves, and more.
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Is this true or false ?
Answer:
Its true
Explanation:
Distance time graphs
50 POINTS
Gizmos Moles Activity - chemistry
can someone please help me out
there is how I would answer it.
What is the molar mass of Fe2(CO3)3?
Answer:
291.7167
Explanation:
The molar mass of Fe₂(CO₃)₃ is 291.714 g/mol.
To calculate the molar mass of Fe₂(CO₃)₃, we need to consider the atomic masses of the individual elements present in the compound.
The molar mass of each element is as follows:
Fe (iron): 55.845 g/mol
C (carbon): 12.011 g/mol
O (oxygen): 15.999 g/mol
Now, let's calculate the molar mass of Fe₂(CO₃)₃:
Molar mass = (2 × atomic mass of Fe) + (3 × atomic mass of C) + (9 × atomic mass of O)
Molar mass = (2 × 55.845 g/mol) + (3 × 12.011 g/mol) + (9 × 15.999 g/mol)
Molar mass = 111.69 g/mol + 36.033 g/mol + 143.991 g/mol
Molar mass = 291.714 g/mol
Therefore, the molar mass of Fe₂(CO₃)₃ is approximately 291.714 g/mol.
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80 grams of water releases 2550 joules of heat. What is the temperature change of the water? Heat capacity of water is 4.2 J/g°C.
Answer:
7.59°C
Explanation:
Using the formula;
Q = m × c × ∆T
Where;
Q = amount of heat (joules)
m = mass of substance (g)
c = specific heat capacity (J/g°C)
∆T = change in temperature (°C)
According to this question;
m = 80g
c = 4.2 J/g°C.
Q = 2550J
∆T = ?
Using Q = m × c × ∆T
∆T = Q/mc
∆T = 2550 ÷ (80 × 4.2)
∆T = 2550 ÷ 336
∆T = 7.589°C
The change in temperature of water = 7.59°C.
the temperature will decrease the rate of reactions.
Answer:
true?
Explanation:
WILL MARK BRAINLEST
Which of the following are sources of greenhouse gasses? Select all that apply
a
Bike Riding
b
Cow Farts
c
Growing Trees
d
Burning Coal
e
Car Exhaust
Answer:
b and c
Explanation:
sorry if i'm wrong
Answer:
b, c, d, e
Explanation:
PLEASE HELP AND FAST!! How many grams of NH4OH are in 0.125L of a 1.4 M solution of NH4OH?
Answer:
6.132
Explanation:
Help if possible!
Picture attached with the problems.
How many planets did early astronomers know about?
Answer:
5 Plants
Explanation:
Also can i have Brainlist
IS ANYONE GOOD WITH CHEMISTRY???! i need help lol
Answer:
Help with what?
Explanation:
Answer:
help with whattt
Explanation:
um
The molar mass of element X is 42.3 grams per mol and the molar mass for
element Y is Y 96.7 grams per mol. What is the empirical formula for a substance
containing a mass composition of 52.2% X and the remainder Y?
Answer:
X5Y2
Explanation:
% composition of X = 52.2%
% composition of Y = (100 - 52.2) = 47.8%
This means that there are 52.2g of X and 47.8g of Y in the compound
To calculate the empirical formula of the compound, we first convert the gram value to mole value by dividing by their molar masses.
X = 52.2g/42.3g/mol = 1.234mol
Y = 47.8g/96.7g/mol = 0.494mol
Next, we divide each mole value by the smallest value (0.494mol)
X = 1.234mol ÷ 0.494mol = 2.49
Y = 0.494mol ÷ 0.494mol = 1
We multiply each value by 2
X = 2.49 × 2 = 4.98
Y = 1 × 2 = 2
The simple ratio of X:Y is 5:2, hence, their empirical formula is X5Y2.
Name the following base: Ba(OH)2
Answer:
Caustic Base
Explanation:
"Barium hydroxide forms a strong caustic base in aqueous solution. It has many uses, e.g., as a test for sulphides; in pesticides; in the manufacture of alkali and glass. Use of barium hydroxide lime rather than soda lime, high sevoflurane concentration, high absorbent temperature, and fresh absorbent use."
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