Answer:
The sky looks different in each nighttime section of the artifact because the artifact sections represent different seasons. ... Different constellations are visible on different nights throughout the year because of the earth's orbit. The Earth orbits around the sun. A full orbit is 365 days or one year.
Explanation:
A student dissolves 15.0 g of ammonium chloride(NH4Cl) in 250. 0 g of water in a well-insulated open cup. She then observes the temperature of the water fall from 20.0 oC to 16.0 oC over the course of minutes. Use this data, and any information you need from the ALEKS Data resource, to answer the questions below about this reaction:
NH4Cl(s) rightarrow NH4+(aq) + Cl-(aq)
You can make any reasonable assumptions about the physical properties of the solution. Note for advanced students: it's possible the student did not do the experiment carefully, and the values you calculate may not be the same as the known and published values for this reaction.
1. Is this reaction exothermic, endothermic, or neither?
2. If you said the reaction was exothermic or endothermic, calculate the amount of heat that was released or absorbed by the reaction in this case.
3. Calculate the reaction enthalpy deltaHrxn per mole of NH4CI.
Answer:
1) Endothermic.
2) [tex]Q_{rxn}=4435.04J[/tex]
3) [tex]\Delta _rH=15.8kJ/mol[/tex]
Explanation:
Hello there!
1) In this case, for these calorimetry problems, we can realize that since the temperature decreases the reaction is endothermic because it is absorbing heat from the solution, that is why the temperature goes from 22.00 °C to 16.0°C.
2) Now, for the total heat released by the reaction, we first need to assume that all of it is released by the solution since it is possible to assume that the calorimeter is perfectly isolated. In such a way, it is also valid to assume that the specific heat of the solution is 4.184 J/(g°C) as it is mostly water, therefore, the heat released by the reaction is:
[tex]Q_{rxn}=-(15.0g+250.0g)*4.184\frac{J}{g\°C}(16.0-20.0)\°C\\\\ Q_{rxn}=4435.04J[/tex]
3) Finally, since the enthalpy of reaction is calculated by dividing the heat released by the reaction over the moles of the solute, in this case NH4Cl, we proceed as follows:
[tex]\Delta _rH=\frac{ Q_{rxn}}{n}\\\\\Delta _rH= \frac{ 4435.04J}{15.0g*\frac{1mol}{53.49g} } *\frac{1kJ}{1000J} \\\\\Delta _rH=15.8kJ/mol[/tex]
Best regards!
Best regards!
What type of intermolecular forces occur between 2 oil molecules?
Answer:
The three main kinds of intermolecular interactions are dipole-dipole interactions, London dispersion forces, and hydrogen bonds
Explanation:
What do particulates in the atmosphere do?
A: They trap heat
B: They help plants to grow better
C: They shield Earth's surface from harmful solar radiation
D: They nucleate water vapor to form clouds.
Can light bend around corners to reach an object
Answer: Yes, light can bend around corners. In fact, light always bends around corners to some extent.
Explanation:This is a basic property of light and all other waves. ... The ability of light to bend around corners is also known as "diffraction".
. Give an example of a salt that is less soluble when the temperature increases
Answer:
cerium (iii) sulfate is less soluble
Answer:
cerium sulphate is less solube when the temperature increase
How many milliliters of a 25% (m/v) NaOH solution would contain 75 g of NaOH?
A 19 mL
B) 25 mL
C
33 mL
D
75 mL
E
3.0 x 102 mL
Answer:
E 3.0 x 10² mL.
Explanation:
Hello there!
In this case, according to the formula for the calculation of the mass-volume percent:
[tex]\% m/V=\frac{m_{solute}}{V_{solution}}*100\%[/tex]
Whereas it is necessary to know the mass of the solute and the volume of the solution. Thus, given the mass of NaOH as the solute, the volume of the solution would be:
[tex]V_{solution}=\frac{m_{solute}}{\% m/V}*100\%[/tex]
Then, by plugging in we obtain:
[tex]V_{solution}=\frac{75g}{25\%}*100\%\\\\V_{solution}=3.0x10^2mL[/tex]
Thus, the answer is E 3.0 x 10² mL.
Best regards!
Which of the following methods of fossil formation is formed in dry areas due to a lack of moisture?
a
Mummification
b
Casts and molds
c
Amber fossil
d
Carbonization
The methods of fossil formation in dry areas due to a lack of moisture is mummification. The correct option is a.
What is mummification?Mummification is the process of deliberately drying or embalming flesh to preserve the body after death.
This typically entailed removing moisture from a deceased body and desiccating the flesh and organs with chemicals or natural preservatives such as resin.
Mummification served the purpose of keeping the body intact so that it could be transported to a spiritual afterlife.
The body was stripped, positioned on a slanted table, and washed in natron solution (a naturally occurring salt used both as soap and a preservative).
The brain was extracted from the skull through a hole in the ethmoid bone (the bone separating the nasal cavity from the skull cavity).
Thus, the correct option is A.
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Titrations provide a method of quantitatively measuring the concentration of an unknown solution.
a. Trueb. False
Answer: True
Explanation:
Titration is a quantitative technique where a solution of known concentration is used to determine the concentration of an unknown solution. The titrant (the known solution) is added from a burette to a known quantity of the the unknown solution until the reaction is complete.
By knowing the volume of titrant, we can determine the concentration of the unknown.
Thus the statement Titrations provide a method of quantitatively measuring the concentration of an unknown solution is True .
How many moles are contained in 2.3 liters of a 1.2M solution?
Answer:
[tex]\boxed {\boxed {\sf 2.76 \ mol}}[/tex]
Explanation:
Molarity is found by dividing the moles of solute by liters of solution.
[tex]molarity = \frac {moles}{liters}[/tex]
We know the molarity is 1.2 M (mol\liter) and there are 2.3 liters of solution. Substitute the known values into the formula.
[tex]1.2 \ mol/liter= \frac {x}{2.3 \ liters}[/tex]
Since we are solving for x, we must isolate the variable. It is being divided by 2.3 and the inverse of division is multiplication. Multiply both sides by 2.3 liters.
[tex]2.3 \ liters *1.2 \ mol/liter= \frac {x}{2.3 \ liters}* 2.3 \ liters\\2.3 *1.2 \ mol= x\\2.76 \ mol =x[/tex]
In a solution with a molarity of 1.2 and 2.3 liters of solution, there are 2.76 moles.
Which sublevels hold valence electrons?
Answer:
The Periodic Table can be divided into s, d, p, and f sublevel blocks. For elements in the s sublevel block, all valence electrons are found in s orbitals. For elements in the p sublevel block, the highest energy valence electrons are found in p orbitals.
Explanation:
Potential and kinetic energy are similar in that -
COME ON BESTIES I NEED HELP
Answer:
They refer to energy that moves. Kinetic energy is energy that is currently moving. Potential refers to energy that has yet to move, or simply energy in wait
Explanation:
Answer:
I'm not 100% but a possible answer could be: No energy could either be created or destroyed
LMK if not but good luck!
A compound containing nitrogen and oxygen is decomposed in the laboratory. It produces 24.5 g nitrogen and 70.0 g oxygen. Calculate the empirical formula of the compound.
Answer:
N2O5
Explanation:
1. Convert to moles
24.5g N * 1mol/14g = 1.75
70.0g * 1mol/16g = 4.375
2. Divide each value by the smallest
1.75/1.75 = 1
4.375/1.75 = 2.5
3. Multiply each by a whole number so that they are both whole numbers
1*2 = 2
2.5*2 = 5
4. These are moles of elements present in the compound
Answer: N2O5
Question: You decompose a compound containing nitrogen and oxygen in the laboratory and produce 24.5 g of nitrogen and 70.0 g of oxygen. Calculate the empirical formula of the compound.
About how many atoms of Mg are present in 24.3 grams of Mg?
5.85 x 1025
4.35 x 1019
c
4.81 X 1024
6.02 x 103
Answer:
D is the answer i think
Explanation:
Hydrogen chloride dissolved in water yields hydrochloric acid. What is the
molar concentration of HCl if 3.65 g of hydrogen chloride is dissolved in 500 mL of
water?
Answer:
1500ml
Explanation:
molarity=3.65⋅g36.5⋅g⋅mol−1500⋅mL×10−3⋅L⋅mL−1=0.200⋅mol⋅L−1
The local weather station is predicting that a warm front will pass through Charlotte, NC in two days.
How will Charlotte's weather most likely be affected by the passing of a warm front?
A The wind speed will decrease.
B The air pressure will increase.
C the temperature will increase.
D The temperature will decrease.
Answer:
C the temperature will increase.
Calculate the molality of a solution containing 15.0 g of ethylene glycol (C2H6O2) dissolved in 145 g of water.
Answer:
Molarity=moles of solute/ L of solution
Molality = moles of solute/ kg of solvent
Solute= what is being dissolved
Solvent= what is doing the dissolving
Solution= both together
Explanation:
Example's:
#1. For number one you use the Molarity formula. M= moles of solute/ L of solution.
To find moles of Mg(NO3)2 you divide 95g by its molar mass which is 148.33g so 95/148.33=.6405 moles of Mg(NO3)2. Then plug in what you have. .38M= .6405 moles Mg(NO3)2 / X. Then solve for X using algebra. .6405/.38= 1.686 L of solution. (Volume).
Final Answer: 1.686 L
#2. For number 2 you use the Molality formula. m= moles of solute/ kg of solvent.
First you have to find moles of glucose by taking 267g and dividing it by its molar mass which is 180.56g. 267g/180.56g= 1.532 moles of glucose. Then you have to change L to kg. The easiest way to do this is to look at the density and see that for every 1 ml there is 1 gram. So to take Liters to ml you multiply 1.59 by 1000 and get 1590 ml. So that means you have 1590 grams. then you divide 1590grams by 1000 to get 1.59 Kg of slovent. Then plug in your information into the formula. molality= 1.532 moles of glucose / 1.59 Kg of solvent= .964 molality.
Final answer: .964 mol/Kg
#3. m= moles of solute / Kg of solvent. 0.445 mol solute / 2.07 Kg solvent= .215 Molality
Final Answer: .215 mol/Kg
#4. m= moles of solute / Kg of solvent. take 13.5g and divide it by ethylene glycols molar mass which is 62.068 g. 13.5g / 62.068g= .218 mol. Then you take 135g of water and divide it by 1000 to get Kg. 135/1000=.135 Kg. Then plug in your information. m= .218mol/.135 Kg= 1.615 molality
Final Answer: 1.615 mol/Kg.
Dominant traits are more common in a population then recessive traits
false
true
Answer:
No Just because a trait is dominant does not mean that it is present in the population
Explanation:
How many significant figures are in the number 420,000 mi?
Answer:
2
Explanation:
zeros are not considered sig figs
What is a biome?
Question 1 options:
An area with lots of of rainfall.
An area with the same climate, landscape, plants, and animals.
An area with different temperatures.
A bunch of trees, forests, and rivers.
Answer:
An area with the same climate, landscape, plants, and animals.
A balloon at 30.0 C has a volume of 222 ml. if the temperature is increased to 62.1 C and the pressure remains constant, what will the new volume be, in mL?
The concept Charles's law is used here to determine the new volume. At the condition of constant pressure the new volume of the balloon is 459.54 mL.
What is Charles's law?At constant pressure, the volume of a given mass of gas is directly proportional to the temperature on Kelvin scale. Mathematically, the law can be expressed as follows:
V = constant × Temperature
V / T = Constant
V = Volume
T = Temperature
The Charles's law also explained that at -273°C, the volume of all the gases will become zero. This temperature is defined as the absolute zero.
For two different gases with volumes V₁ and V₂ and temperatures T₁ and T₂ is represented as:
V₁ / T₁ = V₂ / T₂
V₂ = V₁T₂ / T₁
222 × 62.1 / 30.0 = 459.54 mL
Thus the new volume of balloon is 459.54 mL.
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how do you think a device could change the sound that we hear? Make sure you use vocabulary such as frequency, energy and amplitude
Answer:
good luck tho
Explanation:
why phenol is more acid than alcohol????
Answer:
Phenol is more acidic than alcohol due to resonance stabilization of the phenoxide ion.
Wind energy is a renewable natural resource
True
False
this is true, wind energy is a renewable natural resource c:
how many ions does magnesium phosphite have? how many of those are anions? please explain thought process.
Answer:
We can simply refer to the cation in the ionic compound as magnesium. Phosphorus, Pstart text, P, end text, is a group 15 element and therefore forms 3- anions.
Explanation:
Because it is an anion, we add the suffix -ide to its name to get phosphide as the name of the ion.
Why isn't salt water safe for humans to drink?
O A. Salt water has too many water molecules and too few salt molecules.
B. Salt water has too few water molecules and too many salt molecules.
O
C. Salt water contains molecules that are poisonous to humans.
O
D. Salt water contains molecules that are too large for humans to process.
Answer:
B. Salt water has too few water molecules and too many salt molecules
Explanation:
Seawater is toxic to humans because your body is unable to get rid of the salt that comes from seawater. Your body normally gets rid of excess salt by having the kidneys produce urine, but it needs freshwater to dilute the salt in your body for the kidneys to work properly.
How many molecules of O2 will be formed from 0.500 grams of KCIO3
Answer:
3.7 x 10²¹ O₂ molecules
Explanation:
2KClO₃ => 2KCl + 3O₂
given 0.500g KClO₃ => 0.500g/122.55g/mol = 0.0041 mole KClO₃
0.0041 mole KClO₃ => 3/2(0.0041) mole O₂ = 0.0061 mole O₂
0.0061 mole O₂ = 0.0061 mole O₂ x 6.02 x 10²³ molecules O₂/mole O₂
= 3.7 x 10²¹ molecules O₂
Help meee??
HNO 3 is an example of Select one :
Triprotic Acid
O Diprotic Acid
O Monoprotic Acid
Tetraprotic Acid
A gas is initially at 20.0 o C. That temperature is
K.
The gas is then heated to 30.0 0 C. That temperature is
K.
The initial pressure of the gas is 1.00 atm. The new pressure of the gas is
atm. (Round to 2 decimal places)
Answer:
The temperature of the gas is 293.15 K.
The temperature of the gas is 303.15 K.
The new pressure of the gas is 0.97 atm.
Explanation:
You need to add 273.15 to the Celsius temperature to convert from Celsius to Kelvin.
So,
20.0°C + 273.15 = 293.15 K.
30.0°C + 273.15 = 303.15 K.
We can use the following equation to calculate the new pressure:
[tex]P_2 = P_1 *\frac{T_2}{T_1}[/tex]
where:
P1 is the initial pressure P2 is the final pressureT1 is the initial temperatureT2 is the final temperaturePlugging in the values from the problem, we get:
[tex]P_2 = 1.00 atm * \frac{303.15 K }{293.15 K} = 0.97 atm[/tex]
Therefore, the new pressure of the gas is 0.97 atm.
5 ways light changes objects
Why do scorpions glow on a black light?
Answer:
All scorpions fluoresce under ultraviolet light, such as an electric black light or natural moonlight. The blue-green glow comes from a substance found in the hyaline layer, a very thin but super tough coating in a part of the scorpion's exoskeleton called the cuticle
Explanation:
Answer:
All scorpions fluoresce under ultraviolet light, such as an electric black light or natural moonlight. Much like many other creepy, crawly insects, scorpions like hiding in dark places. ... If you're worried that you may have a scorpion problem, you can use a black light to search for them at night. When a black light hits a scorpion, the proteins on its exoskeleton create a bright neon blue hue.Scorpions do not like heat and bright light. They lose some of what little water they have to evaporation. So they use their sensitivity to UV rays to determine if it's dim enough for them to crawl out and get to business. He thinks that scorpions glow to convert the dim UV light from the moon and the stars into the colour that they see best – blue-green. This could explain why scorpion eyes are so exquisitely sensitive, to the point where they can detect the faint glow of starlight against the background of the night sky.Given the high densities of scorpions in some areas, their importance in ecological food webs, particularly with respect to helping control insect populations, is considerable. Many are sensitive to environmental degradation and are considered equilibrium species. Ecology: Scorpions are primarily nocturnal.Scorpions are preyed upon by large centipedes, tarantulas, lizards, birds (especially owls), and mammals such as bats, shrews, and grasshopper mice.
Explanation: I added a little more info about them please give me brainliest