Answer:
The molarity of ethanol is 5.8*10⁻³ M.
Explanation:
Molar concentration is a measure of the concentration of a solute in a solution, be it some molecular, ionic or atomic species.
Molarity or Molar Concentration is the number of moles of solute that are dissolved in a certain volume. It is calculated by dividing the moles of the solute by the volume of the solution:
[tex]Molarity=\frac{number of moles of solute}{volume}[/tex]
Molarity is expressed in units [tex]\frac{moles}{liter}[/tex].
Being the molar mass of ethanol 46 [tex]\frac{g}{mol}[/tex], then the number of moles that 40 grams of ethanol contain is calculated by:
[tex]40 grams*\frac{1 mol}{46 grams} =0.87 moles[/tex]
So, being:
number of moles of solute= 0.87 molesvolume 150 LReplacing in the definition of molarity:
[tex]Molarity=\frac{0.87 moles}{150 L}[/tex]
Solving:
Molarity= 5.8*10⁻³ M
The molarity of ethanol is 5.8*10⁻³ M.
A fire is an example of an exothermic reaction. Which of the following best
supports that statement?
A. The fire is creating energy.
B. The fire is releasing energy.
C. The fire is capturing energy.
D. The fire is destroying energy.
Answer: B. Fire is releasing energy
Explanation:
Acid-base neutralization means having a pH of 7. true or false ?
Answer:
True
Explanation:
A pH of 7 is greater than basic but lesser than acidic. Therefore, it's neutral
A 600-ml solution of alcohol contains 350 mL of water. What
is the mass percent of alcohol?
answer options:
41.7 % alcohol solution
71.4 % alcohol solution
2.5 % alcohol solution
40% alcohol solution
A student places three ice cubes in a beaker and allows them to partially melt. If she measures the temperature of the water in the beaker, what will she most likely observe? Explain your answer.
**Check for proof photos at the bottom.**
**Answers are in bold.**
__________________________________________________________
A student places three ice cubes in a beaker and allows them to partially melt. If she measures the temperature of the water in the beaker, what will she most likely observe? Explain your answer.
She will see that the temperature of the water is 0 degrees Celsius and it stays at that temperature until all the ice cubes completely melt.
__________________________________________________________
Use the table on the right to calculate each required quantity. Record values to 3 significant digits.
First answer: 35.8 kJ
Second answer: 871 g
Third answer: Fe
__________________________________________________________
An iron sphere with a mass of 75.00 g is heated to a temperature of 385.0°C. It is then placed in a beaker containing 150.0 g H2O at 100.0°C.
First answer: 339 kJ
Second answer: 9.02 kJ
Third answer: No
__________________________________________________________
A sample of water has a mass of 100.0 g. Calculate the amount of heat required to change the sample from ice at –45.00°C to water vapor at 175.0°C. Relevant constant values are given to the right.
First answer: 325 kJ
Second answer: boiling the water
__________________________________________________________
Identify the correct description for each part labeled on the diagram.
A: ✔ heating solid
B: ✔ melting
C: ✔ heating liquid
D: ✔ boiling
E: ✔ heating gas
F: ✔ melting point
G: ✔ boiling point
Where are the particles closest together?
✔ A
Explanation:When ice partially melts, the surrounding water remains at 0° Celsius. This is because ice melting only involves the water molecules overcoming intermolecular forces, or forces holding molecules together. The water molecules themselves aren't increasing in kinetic energy when turning into liquid. Since temperature measures kinetic energy, the temperature in this case, remains at 0°.
To find how much energy it takes to cause a phase change in a substance, you must find the number of moles, and determine whether to use ΔHvap and ΔHfus. ΔHvap is used to show how much energy is involved in evaporation and condensation, and ΔHfus is the same but used for melting and freezing. To find number of moles of a given substance, use the formula: mass of given substance divided by atomic mass. Both numbers have to use the same mass unit. Then, multiply number of moles by ΔHvap or ΔHfus to get kJ.
In a heating curve graph, the flat lines represent no change in energy, or the phase changes. The steep lines are change in energy, which are either heating or cooling. The bottom line is a heating/cooling solid. A heating/cooling solid is the coldest phase, which is why the line is at the bottom.
Here are photos of Edge to make things easier.
Why does breaking up a solid reactant increase the rate of reaction?
Question 2 options:
a)
it creates more solid
b)
it increases the concentration
c)
it increases the surface area
d)
it creates more energy
Answer:
B...
Explanation:
sorry if i got it wrong, mines was right..Gas particles that are at low temperature and high pressure and are close to changing phases are considered:
a)Real Gases
b)Ideal Gases
c)Both Ideal and Real Gases
A hot metal is placed in 100.0 g sample of water and it causes the temperature of the water to increase from 25 C to 27 C. How many joules of energy did the water absorb from the metal?
Answer: [tex]836.8\ J[/tex]
Explanation:
Given
Mass of water in the sample is [tex]m=100\ g[/tex]
Temperature changes from [tex]25^{\circ}C[/tex] to [tex]27^{\circ}C[/tex]
Change in temperature is [tex]\Delta T=27-25=2^{\circ}C\ \text{or}\ 2\ K[/tex]
We know, specific heat of water is [tex]c=4.184\ J/g-K[/tex]
Heat absorbed is given by
[tex]\Rightarrow Q=mc\Delta T\\\Rightarrow Q=100\times 4.184\times 2\\\Rightarrow Q=836.8\ J[/tex]
Thus, water absorbs [tex]836.8\ J[/tex] of heat from hot plate.
A boy inherited genes that would ordinarily allow him to grow tall.his growth is stunted as a result of poor nutrition.this is an example of
Fossil fuels are made up of
A. aromatic hydrocarbons
B. acids
C. hydrocarbons
D. optical isomers
Answer:
I think its option C
Explanation:
Answer:
C. Hydrocarbons
Explanation:
I think it is C
list the universities of nepal and explain about one of them.
Answer:
Tribhuvan University is a university in Tribhuvan, Nepal. Tribhuvan University (TU) is a pioneering higher education institution in Nepal, having been founded in 1959. ......
Pokhara University... Kathmandu University...
Purbanchal University is located in Purbanchal, India.
Lumbini Bauddha University (LBU) is a university in Lumbini, Nepal...
Nepal Sanskrit University is a university dedicated to the study of Sanskrit in Nepal.
Midwestern University is a public university in the Midwest...
Nepal Open University is a public university in Nepal.
Explanation:
I have prepared a caffeine stock solution of 0.075 M. What volume should we mix with
distilled water in order to reach a standard solution of 0.0015 M and a final volume of 10
mL?
a) 0.2 mL
b) 112.5 mL
c) 50 mL
d) 2 mL
PLEASE HELP!
No Links!
I will award brainliest to the first person to answer
Answer:
I think 50 ml but I am not sure
sorry
What is the pH of a solution with a 3.2 x 10-5 M hydronium ion concentration? (5 points)
4.3
11
4.5
12.
Answer: 4.5
Explanation: Got it right on the exam. Hope this helps!
What is scientific method? a. A plane for forming a scientific hypothesis. b. A technique for carrying out a scientific explement c. A formula for analyzing scientific data d. An organized way to test scientific ideas
Answer:
d. An organized way to test scientific ideas
Explanation:
Science can be defined as a branch of intellectual and practical study which systematically observe a body of fact in relation to the structure and behavior of non-living and living organisms (animals, plants and humans) in the natural world through experiments.
An experiment can be defined as an investigation which typically involves the process of manipulating an independent variable (the cause) in order to be able to determine or measure the dependent variable (the effect).
This ultimately implies that, an experiment can be used by scientists to show or demonstrate how a condition causes or gives rise to another i.e cause and effect, influence, behavior, etc in a sample.
A scientific method can be defined as a research method that typically involves the use of experimental and mathematical techniques which comprises of a series of steps such as systematic observation, measurement, and analysis to formulate, test and modify a hypothesis.
A hypothesis is considered to be tentative or an educated guess and can be defined as a testable explanation for an observation or a scientific problem. An example of a hypothesis is saying, Corona virus is caused by the introduction of the "5G" technology.
Thus, for any hypothesis to be true and acceptable in science, it must be supported by observations and the results of control experiments; this give rise to factual informations, theories and by extension solutions to problems.
In conclusion, we can deduce from the aforementioned paragraphs that a scientific method is simply an organized way to test scientific ideas and hypothesis.
. A scientist placed a sample of lithium into a container of water. The scientist observed the lithium floating and making a buzzing sound as gas bubbles were forming around it. Which conclusion is BEST supported by this observation
Answer: The conclusion that best support the observation is that (A CHEMICAL CHANGE took place).
Explanation:
A chemical reaction is defined as the process by which two or more substances, which are often referred to as REACTANTS, combine through bond formation or dissociation of bonds to form new PRODUCTS. In this type of reaction, a CHEMICAL CHANGE occurred because a new substance is formed as a result of the chemical reaction that took place.
There are different characteristics of a reaction which shows that a chemical change has occurred, these includes:
--> Color Change
--> Production of an odor
--> Change of Temperature
--> Evolution of a gas (formation of bubbles)
-- Precipitate (formation of a solid)
From the chemical reaction in the given question, Lithium metals reacts slowly with water to form a colourless solution of lithium hydroxide (LiOH) and hydrogen gas (H2). Here we observe that the buzzing sound of formed gas bubbles shows that a gas was given off. Therefore in conclusion, a CHEMICAL CHANGE took place.
please answer cansend to me
Balance this chemical equation
Ca(OH)2 + HCl ---> CaCl2 + H2O
Answer:
The balance equation of Ca(OH)2 + HCl ---> CaCl2 + H2O
is
Ca(OH)2(s) + 2HCl(aq) ---> CaCl2(aq) +2H2O (l) (balanced equation)
Please help me. I am doing a test and, I don’t know this one.
Answer: 22
Explanation:
The reaction is run at two temperatures where temperature 1 is lower than temperature 2. Which relationship is correct for either rate constant (k1 or k2) or activation energy (Ea,1 and Ea,2)
Answer:
The answer is "[tex]K_1 < K_2[/tex]"
Explanation:
In the given question, the value of the [tex]K=Ae^{-\frac{Ea}{RT}}[/tex] and the [tex]T_1 <T_2[/tex]is the rate value which is the constant that is [tex]K_2>K_1[/tex]. As per the temperature value when its increase rate is constantly increasing. [tex]E_a[/tex] is activation energy it is not dependent on the temperature that why the answer is [tex]K_1 < K_2[/tex].
The term “ sea of electrons “ refers to
Answer:
Explanation:
Basically in metallic bonds, valence electrons are not localied which means they can freely move from one atom to another. Thus, they move in "sea of electrons" because in a sea water or waves are freely moving without any localization.
Hope that helps.
You have 11.27 moles of Cl2 gas. How many moles of NaBr do you need to completely undergo this reaction?
Answer:
22.54 moles of NaBr are needed
Explanation:
The reaction of Cl2 with NaBr occurs as follows:
Cl2 + 2NaBr → 2NaCl + Br2
Where 1 mole of Cl2 requires 2 moles of NaBr for a complete reaction
As in the problem, we have 11.27 moles of Cl2, the moles of NaBr required are:
11.27mol Cl2 * (2mol NaBr / 1mol Br2) =
22.54 moles of NaBr are neededHelp please ! ASAP neeeeeed and answerrrrrr
Answer:
The answer is D
Explanation:
Answer:
A. Heater will only become warm when switch is closed.
Explanation:
Switches are used to control the flow of electrons (basically electricity). If you look at the other trials, you see that when switch is open, the bulb or fan does not run cuz no electricity can get to them. But when switch is closed, electricity gets to them. Thus, they will experience similar thing with the heater I assume cuz they have not said anything about battery voltage or anything preventing heater from heating.
What are the columns on the periodic table called?
(2.5 Points)
Answer:
A group is a column of elements in the periodic table of the chemical elements.
So, the columns on the periodic table are called groups.
11
1. If 325 grams of sodium nitrate are added to water to make the total solution volume 5.5 L,
what is the concentration (molarity) of this solution?
Answer: 0.695 mol/L
Explanation:
To find the final concentration of the solution, we must first identify the moles of the solute (NaNO₃):
moles = mass ÷ molar mass
∴ moles of NaNO₃ = 325 g ÷ 84.995 g/mol
= 3.824 mol
Now, since the final volume is 5.5 L and this volume contains the 3.824 moles of NaNO₃,
then the molarity of the solution = 3.824 mol ÷ 5.5 L
= 0.695 mol/L
You decide to race your buddy after school. The race starts at the 10 yard line and ends at the 50 yard line. How long was the race
Answer:
Long of the race = 40 yard
Explanation:
The long of the race is measured from the distance in the beginning (10 yard line) to the distance and the end of the race (50 yard line). The distance of the race is the difference between both lines. That is:
Long of the race = 50 yard - 10 yard
Long of the race = 40 yard
Why does Watney get left behind on Mars?
Answer:
I think it's because he was presumed dead after a storm, or like a problem with his suit
Explanation: I think it was because somebody thought he was dead in the storm? And the remaining of the crew were forced to leave him behind thinking he was dead on mars.
I might be right, might not ^^
Global average temperature increases when energy absorbed by the surface ___?
increases
decreases
remains the same
Answer:
Increases
Explanation:
The main reason of increase earth's temperature is the increase of CO2 gas in the air which causes global warming and the ice burgs in the poles are getting melted and it results in the increase of the sea water level.
This is the main our problem in the future.
Can someone help me with this?
A chemist prepares a solution of silver perchlorate (Agcio) by measuring out 0.91 kg of silver perchlorate into a 400 ml. volumetric flask and filling the flask
to the mark with water
Calculate the concentration in mol L of the chemist's silver perchlorate solution. Be sure your answer has the correct number of significant digits.
Answer:
오빠nsuensojee9ejenheie
Can the excess reactant control the percentage yield
The compound consists of 40.1% carbon, 6.6% hydrogen and 53.3% oxygen. Its relative density with respect to hydrogen is -15. What is the formula of the compound?
Answer:
https://socratic.org/answers/220339
this is the answer , my grandpa create this page
Explanation: