Answer:
Freezing T° of solution = - 7.35 °C
Explanation:
This is about the freezing point depression, a colligative property which depends on solute.
The formula is: Freezing T° pure solvent - Freezing T° solution = m . Kf . i
Freezing T° of pure solvent is -3.1°C
At this case, i = 1. As an organic compound the urea does not ionize.
We determine the molality (mol/kg of solvent)
We convert mass to moles:
12.3 g . 1mol / 60.06 g = 0.205 moles
0.205 mol / 0.3 kg = 0.682 mol/kg
We replace data in the formula:
-3.1°C - Freezing T° of solution = 0.682 mol/kg . 6.23 kg°C/mol . 1
Freezing T° of solution = 0.682 mol/kg . 6.23 kg°C/mol . 1 + 3.1°C
Freezing T° of solution = - 7.35 °C
You heat 51 grams of magnesium over a Bunsen burner for several minutes until it reacts with oxygen in the air. Then you weigh the resulting product and see that it is now 53 grams. How does this happen without breaking the Law of Conservation of Mass?
Answer:
The mass was there all along, it was just in the air. The weight of the oxygen from the air is not weighed in the beginning, only at the end as part of the product, making it seem like there is a total mass change.
The two forces acting on a boat or some other floating object are________
and gravity.
Answer:
buoyancy. ...
Explanation:
........
Answer:
buoyancy
Explanation:
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If your front lawn is 25.0 feet wide and 20.0 feet long, and each square foot of lawn accumulates 1350 new snowflakes every minute, how much snow, in kilograms, accumulates on your lawn per hour? Assume an average snowflake has a mass of 1.90 mg.
Answer:
19.17 kgExplanation:
calculate area of lawn
25 * 20 = 500 sq ft
calculate how many flakes fall per minute
500 * 1150 = 575 , 000 flakes/minute
convert per minute rate to per hour rate
575 , 000 * 60 = 34 ,500 , 000 flakes/hour
now you know how many flakes feel in that one hour so we can now weigh them
34 , 500 , 000 / 1.8 = 19 , 166 , 667 mg (rounded)
convert to kilograms
19 , 166 , 667 / 100 , 000 = 19.17 kg (rounded)
Using the brønsted theory, classify the compounds as either an acid or a base
1. HCOO-
2. HNO3
3. -CH3COOCH3
4. HCOOH
Answer:
all the below are ACIDS
Explanation:
1.HCOO- Formate
HCOO- is a conjugate base.
2.HNO3- Nitric Acid
Acid
3.CH3COOCH3: Methyl acetate
Acid
4. HCOOH: Formic Acid
Acid
Hope it helps..pls mark as brainliest!
BRAINLIEST PLEASE HELP WITH THIS CHEMISTRY QUESTION!!
Which of the following describes how further studies supported the work done by Ernest Rutherford?
Answer: James Chadwick discovered neutral particles in the nucleus. So your answer is C
Explanation:
I just took a pretest and I had this same question and I got it right
Answer:
James Chadwick discovered neutral particles in the nucleus.
A jet airplane flies from St. Louis, Missouri, to Phoenix, Arizona, in 3 hrs. The distance is
1,500 miles. What is the plane's speed ?
Answer:
Distance = 1500miles
time taken = 3 hours
speed of plane = distance/time taken = 1500/3= 500milesperhour
Explanation:
According to the distance formula , the speed of the plane is 500 miles per hour.
What is speed?The speed of an object is the magnitude of the change of its position over time or the magnitude of the change of its position per unit interval of time indicating that it is thus a scalar quantity.The average speed of an object in an interval of time is the distance traveled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as the duration of the time interval approaches zero. Speed is not the same as velocity.
Speed has the dimensions of distance divided by time. The SI unit of speed is the metre per second (m/s), but the most common unit of speed in everyday usage is the kilometre per hour (km/h) or in the US and the UK, miles per hour (mph).
Here, speed is calculated as distance /time= 1500/3= 500 miles per hour.
Thus, the speed of plane is 500 miles per hour.
Learn more about speed,here:
https://brainly.com/question/7359669
#SPJ2
How do you find the average density?
Answer:
total mass divided by its total volume
Explanation:
Not divisible
O atom
O compound
O mixture
O solution
Answer:
mixture or atom
Explanation:
I HOPE IT WILL HELP YOU
Explanation:
and ,answer is mixture.
You left a glass full of water by a window in your house in the morning. Three hours later you walk by the glass, and the water level is significantly lower than it was in the morning. You have made the observation that the water level in the cup is lower. Then, you ask the following question: “Why is the water level in the cup lower?” What is a possible hypothesis you could make?
Which of the following isotopes are NMR inactive?
a. 1H
b. 12C
c. 15N
d. 16o
e. 19F
f. 31P
Answer:
12C and 16O
Explanation:
Here, we want to select which of the options are NMR inactive. For an isotope to be NMR inactive, then the net nuclear spin is zero.
What this means is that the number of proton present coupled with the number of neutrons are an even number pair.
What we are saying here is that the number of protons is an even number while the number of neutrons too is an even number. So the net nuclear spin in this case is zero.
in the case of oxygen, we have 8 protons and 8 neutrons. This makes the nuclear spin zero and consequently makes the isotope NMR inactive.
Same is in the case of carbon. There are 6 protons and 6 neutrons and this also makes nuclear spin zero .
In all the other isotopes in the question, we have odd number even number or even number odd number pairs of protons and neutrons.
how do you tell if an chemical eqaution is unbalanced
3 H2S + 2AuCl --> Au2S3 + 6 HCL is what type
of reaction
Answer:
Double Displacement (Metathesis)
Explanation:
(01.04 LC)
What phase of matter has particles that are held together but can flow past each
other and takes the shape of a container, filling it from the bottom up? (3 points)
1) Gas
2) Liquid
3) Plasma
4) Solid
Which statement describes a property that is unique to metalloids?
Metalloids are shiny.
Metalloids are semiconductive.
Metalloids are solid.
Metalloids are brittle.
Answer:
Metalloids are semiconductive.
Explanation:
Answer: Metalloids are semiconductive.
3 points
What is the energy (Joules) of violet light with a frequency = 3.43 x 10^14
1/s? *
4.54x10^-19 J
1.99x10^-25 J
1.93 x 10^-48 J
O 2.27 x 10^-19 J
Pls help me
Answer:
4.54x10^-19 J
1.99x10^-25 J
1.93 x 10^-48 J
PLEASE HELP ME, I HAVE NO IDEA HOW TO DO THIS :(
Lol . same here. If u get any ideas please let me know
Answer:
See the picture you have to write like this
Which of the following would have the largest pKa?
a. CH3CH2NH+3
b. C6H5NH+3
c. C6H5NH2
d. CH3CH2NH2
Answer:
CH3CH2NH3+/CH3CH2NH2 would have the largest pKa
Explanation:
To answer this question we must know Kb of CH3CH2NH2 is 5.6x10⁻⁴, and for C6H5NH2 is 4.0x10⁻¹⁰. And the CH3CH2NH3+ and C6H5NH3+ are related with these substances because are their conjugate base. That means:
pKa of CH3CH2NH3+ = CH3CH2NH2; C6H5NH3+ = C6H5NH2
Also, Kw / Kb = Ka
Thus:
pKa of CH3CH2NH3+/CH3CH2NH2 is:
Kw / kb = Ka = 1.79x10⁻¹¹
-log Ka = pKa
pKa = 10.75
pKa of C6H5NH3+/ C6H5NH2 is:
Kw / kb = Ka = 2.5x10⁻⁵
-log Ka = pKa
pKa = 4.6
That means CH3CH2NH3+/CH3CH2NH2 would have the largest pKa
what is biotic?check all that apply
Answer: biotic is Living things in their ecological relations.
Explanation:
How do you scientist learn about the moon in other planets
Answer:NASA's Lunar Atmosphere and Dust Environment probe, for instance, orbits the moon and collects information about its atmosphere and surface. This important data can help scientists learn more about moons, asteroids and other objects in the solar system.
Explanation:
Which pair of elements have chemical properties that are most similar
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Answer:
[tex]\large\boxed{(B)}[/tex]
Elements on the periodic table that are the closest in characteristics are in the same group, or column.
Looking at the answer choices, the only two pairs of elements that are in the same group are (B) Al and Ga, as well as (D) F and I.
On the periodic table, Al (Aluminum) and Ga (Gallium) are only one period (row) away from each other, while F (Flourine) and I (Iodine) are 3 periods away.
***Periods determine the number of energy levels and other properties, so elements that are closer to each other would have more similar properties.
Therefore, Aluminum and Gallium contain the most similar chemical properties.
Hover over answer image to enlarge
8)
Which part of the atom cannot have its location accurately determined and is modeled by a cloud around the center of
the atom?
-0)
A)
electron
B)
neutron
nucleus
D)
proton
An atomic nucleus is composed of
)
Which of the following correctly describes a way in which Earth's atmosphere interacts with the biosphere
Answer:
Living organisms breathe gases in the atmosphere.
Explanation:
Answer:
Living organisms breathe gases in the atmosphere.
Explanation:
Biosphere
the regions of the surface, atmosphere, and hydrosphere of the earth (or analogous parts of other planets) occupied by living organisms.
Atmosphere
the envelope of gases surrounding the earth or another planet
why do NH3 and SO3 have different bond angles, even though they have the same number of atoms?
Answer:
Due to different atoms and different values of electronegativities.
Explanation:
NH3 and SO3 have different bond angles because both molecules have different type of atoms combine together. In NH3, nitrogen react with hydrogen while in SO3, sulfur react with oxygen atom. The bond angle of NH3 is 107 while the bond angle of SO3 is 120. This difference in bond angle is also due to different electronegativities of the bonded atoms. The electronegativity of oxygen is higher than hydrogen so repulsion of hydrogen is less and that's why its bond angle is also lower than oxygen.
3. Diesel fuel has a density of 0.839g/mL What is the volume, in gallons, of 2.3 kg of diesel? [1 gallon = 3.79 L)
Answer:
0.71 gal
Explanation:
Step 1: Given data
Density of Diesel (ρ): 0.839 g/mL
Mass of Diesel (m): 2.3 kg
Step 2: Convert "m" to grams
We will use the relationship 1 kg = 10³ g.
2.3 kg × (10³g/1 kg) = 2.3 × 10³ g
Step 3: Calculate the volume (V) of the Diesel sample
We will use the density formula.
ρ = m/V
V = m/ρ
V = 2.3 × 10³ g/(0.839 g/mL)
V = 2.7 × 10³ mL
Step 4: Convert "V" to L
We will use the relationship 1 L = 10³ mL.
2.7 × 10³ mL × (1 L / 10³ mL) = 2.7 L
Step 5: Convert "V" to gal
We will use the relationship 1 gal = 3.79 L.
2.7 L × (1 gal/3.79 L) = 0.71 gal
Answer:
2.3 kg x1000 g/kg = 2300 g
2300 g x 1 ml/0.839 g = 2741 ml
2741 ml x 1 L/1000 ml = 2.741 L
2.741 L x 1 gal/3.79 L = 0.72 gallons
Explanation:
Write 0.00103 in scientific notation
Answer:
1.03
Explanation:
You would take 0.00103 and move the decimal like this; 0001.03, we wouldn't have the zeroes in front of the one, as it can throw us off. Therefore, your answer would be 1.03.
Hope I helped! Don't hesitate to let me know if I made a mistake.
In the following atomic model, where does the strong nuclear force happen?
Answer:
the strong nuclear force happens in the neuclus
Consider the following balanced equation:3Ca(NO3)2(aq) + 2Na3PO4(aq) → Ca3(PO4)2(s) + 6NaNO3(aq)If 24.2 moles of Na3PO4(aq) reacts with an excess of Ca(NO3)2(aq) to produce 50.6 moles of NaNO3(aq), what is the percent yield of the reaction?
Answer:
69.7% is percent yield
Explanation:
Based on the reaction:
3Ca(NO3)2(aq) + 2Na3PO4(aq) → Ca3(PO4)2(s) + 6NaNO3(aq)
2 moles of Na3PO4 react producing 6 moles of NaNO3.
As 24.2 moles of Na3PO4 react, theoretical moles of NaNO3 produced are:
24.2 moles Na3PO4 * (6 moles NaNO3 / 2 moles Na3PO4) =
72.6 moles of NaNO3
As there are produced 50.6 moles of NaNO3, percent yield is:
50.6 moles NaNO3 / 72.6 moles NaNO3 =
69.7% is percent yieldBrian's aunt has cats. When Brian recently visited her, he started sneezing badly and believes that it was because
he is allergic to cats.
What would be the next step for Brian to form a hypothesis?
O by avoiding going to his aunt's house
by wearing a nose mask near cats
by visiting other households with cats
O by visiting his aunt's house again with the cats outside
Answer:
By visiting other households with cats.
Explanation:
This will give Brian a variety of other houses and determine if it is truly cats or just alleries from other items. This is the most direct way to get Brian the answer he is looking for.
Answer:
c
Explanation:
i just did it
Can someone help me with example #1 please
Answer: 343 K
Explanation:
To convert Celsius to Kelvin, you would add 273 to Celsius.
70°C+273=343 K
Now, we know that 70°C is 343 K.
When Z-4,5-dimethyloct-4-ene is treated with hydrogen chloride, HCl, the result is:________.
A. 4 stereoisomers
B. None of these
c. a pair of diastereomers
D. a racemic mixture OS a meso compound
Answer:
The correct option is c
Explanation:
The chemical equation for the reaction of Z-4,5-dimethyloct-4-ene and HCl is shown on the first uploaded image
Now looking at the product we see that there are two who has four different groups attached to them this carbon are known as chiral carbons hence the product formed is a pair of diastereomers