Answer: 0.050 moles of NaOH
Explanation: The molar mass of NaOH is 40.0g/mole
2.0g/40.0g/mole = 0.050 moles (2 sig fig)
A pan containing 20.0 grams of water was allowed to cool from a temperature of 95.0 °C. If the amount of heat released is 1,200 joules, what is the approximate final temperature of the water?
75 °C
78 °C
81 °C
87 °C
Answer:
81 °C
Explanation:
This is a calorimetry question so a few things you will need for this. The calorimetry equation q=mcΔT & the specific heat of water (4.2J/g•°C). Other definitions are:
q = heat added/released by a sample
m = mass of sample
c=specific heat of sample
ΔT = change in temperature
from here we can rearrange the equation to state:
q/(mc) = ΔT
1200J/((20.0g)(4.2J/g•°C)) = ΔT
14°C = ΔT
If the starting temperature was 95.0°C and we know that the temperature was cooled by 14°C then the final temperature of the water would be 81.
Answer:
C. 81 c
Explanation:
took the test :)
What is the mass of six of these marbles? What is the volume? What is the
density?
Answer:
All right. So let's calculate the density of a glass marble. Remember that the formula for density is mass over volume. So if I know that the masses 18.5 g. And I know that the um volume is 6.45 cubic centimeters. I can go ahead and answer this to three significant figures. So it's going to be 2.87 grams per cubic centimeter. Okay, that's our density. Now, density is an intensive process. Okay. We're an intensive property. I really should say. It doesn't depend on how much you have. Mhm. If I have one marble, its density is going to be 2.87 g per cubic centimeter. If I have two marbles, the density will be the same because I'll double the mass and I'll also double the volume. So when I divide them I'll get the same number. Okay, that's what makes it an intensive property. No matter how many marbles I have, they'll have the same density. Mass though is not an intensive property. So if I have six marbles and I want to know what the massive six marbles is. Well, I know the mass of each marble is 18.5 g. So the mass of six marbles Is going to be 100 11 g. Because mass is an extensive property. It depends on how much you have. If I change the number of marbles, I'm going to change the mass. That's an extensive property. All right. So we've calculated the density. We've calculated the mass and then what happens to the density of one marble compared to six marbles as we mentioned before. Since densities and intensive property, the densities will be the same, no matter how may.
Explanation:
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Acrylonitrile and ethyl acetate have the same boiling point: 77.2ºC. In one to two sentences, explain what outcome you would expect if a mixture of these two substances were distilled.
The two substances can never be separated by distillation because distillation depends on difference in boiling point.
Distillation is a separation method that depends on difference in boiling point between two substances.
Usually, the substance having a lower boiling point is collected first as the temperature is gradually raised. The substance having a higher boiling point then follows.
However, since the two substances have the same boiling point, they can not be separated by distillation because they will be converted to vapor simultaneously thereby making separation impossible.
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All the following process produces hematite except
A roasting of siderite
B oxidation of iron
C oxidation of magnetite
D drying of limonite
E no correct answer
Answer:
D)driying of limonite these is the answer
A sample of brass weighing 1.203g was analyzed. The zinc in the alloy was reacted with 35.123g of HCl in excess, according to the balanced equation:
Zn (s) + 2HCl(aq) - > H2(g) + ZnCl2 (aq)
After all the zinc reacted, the mass of the remaining solution weighed 36.309g
What was the mass of H2 produced?
What mass of Zn reacted?
What was the percentage of Zn (by mass) in the alloy?
The number of moles of reactants and products can be used to obtain the mass of products formed. The results obtained are as follows;
The mass of hydrogen produced is 0.0174 gramsThe mass of zinc produced is 0.5688 gramsThe percentage by mass of zinc in the brass alloy is 47.3 %The question says that HCl was in excess. It means that after the reaction, we will have unreacted HCl(aq) and ZnCl2(aq) in the remaining solution.
Hence;
Mass of ZnCl2(aq) formed = 36.309g - 35.123g = 1.186g
Number of moles ZnCl2(aq) formed = [tex]\frac{mass of ZnCl2(aq) formed}{molar mass of ZnCl2}[/tex]
[tex]\frac{1.186g}{136.286 g/mol}[/tex] = 0.0087 moles
From the reaction equation;
[tex]Zn (s) + 2HCl(aq) - > H2(g) + ZnCl2 (aq)[/tex]
To obtain the amount of Zn reacted
1 mole of Zn yields 1 mole of ZnCl2
x moles of Zn yields 0.0087 moles of ZnCl2
x = 0.0087 moles of Zn
a) 1 mole of Zn yields 1 mole of H2
0.0087 moles of Zn yields 0.0087 moles of H2
Mass of H2 = 0.0087 moles of H2 * 2 g/mol = 0.0174 grams
b)
Mass of Zn reacted = 0.0087 moles of Zn * 65.38 grams/mole = 0.5688 grams
c)
Percentage of Zn in the alloy = 0.5688 grams/1.203g * 100 = 47.3 %
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Chemical changes can change which properties of a substance?
Group of answer choices
Reactivity
Color
Malleability
All of the above
Answer:
» Reactivity and color
Explanation:
though color is very minor answer because it also relates to a physical property.
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Which of these answers describes a scientific law?
(Pls)
Answer:
big ablsolty long pp
Explanation:
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Which methods separate a mixture according to the size of the particles?
a
filtration and chromatography
b
distillation and chromatography
c
filtration and evaporation
d
distillation and evaporation
Answer:
filtration and chromatography
Explanation:
I hope this will help you :-)
what is sublimation
Explanation:
Sublimation is the conversion of a substance from the solid to the gaseous state without its becoming liquid. ... Freeze-drying of food to preserve it involves sublimation of water from the food in a frozen state under high vacuum. See also vaporization; phase diagram.
Which of the following statements about alcohols is false?
A. Ethanol is soluble in water.
B. Ethanol has a higher boiling point than ethane.
C. Ethanol produces hydrogen when it burns.
D. None of these
Answer:
It's C. Ethanol produces hydrogen when it burns
When burned, ethanol produces water and CO2.
Revision has a atoMic number of 37 and a mass number of 85. HIW many protons, neutrons and electrons does an ion of rubidium with a 1+ charge have
Answer: 37 protons, 48 neutrons, and 36 electrons.
Explanation: I assume "Revision" is Rubidium. It is atomic number 37, so it has 37 protons. It's atomic mass is 85, so it has an average of (85-37) = 48 neutrons. It has a charge of +1, so one electron of the original 37 has left.
(Physical Science)
Which group of metals includes elements with one valence electron? (1 point)
A. alkaline earth metals
B. rare earth metals
C. alkali metals
D. transition metals
Answer:
C
Explanation:
alkali metals are the Group I elements, which have 1 electron in their valence shells
Answer:
Alkali metals are the elements which have only one valence electron in their outermost or ultimate shell.
Explanation:
Alkaline Earth metals have 2 valence electron in their outermost shell and readily give up their 2 electron to achieve stability.
Rare Earth Metals have 3 valence electron in their outermost shell and they have high magnetic moments and divert range of magnetic structure.
Alkali Earth metals have 1 valence electron.
Transition metals generally have 2 valence electron .
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Plzzzzzz help me Write electronic configuratof sodium and chlorine in the term of subshell ?
Answer:
ans:Ne=2,8,1
ans:2,8,7
Which of these are PHYSICAL changes?
А.
cutting, tearing, freezing, thawing, folding.
mixing without chemical changes
B.
burning, rusting, forming a new substance from
two different substances, exploding, cooking
Answer:
the answer to this problem is a
Compare and contrast the three types of mixtures (solutions, colloids, and suspensions).
Answer:
solutions is a homogenous mixture while colloids and suspensions are heterogeneous mixtures made up of 3 or more substances
Explanation:
homogeneous- made up of one thing
heterogeneous- made up of 2 or more things
cuantos gramos de soluto y solvente tendra 127 gramos de solición cuya concentración es 14% m/m ayuda para resolverlo
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sound travels at 331m/s. How long would it take for sound to travel across lake tahoe, which is 21.6 miles long
Answer:
It would take sound 104.998 seconds to travel across lake tahoe.
Explanation:
First let's convert the miles to meters, so, 21.6 miles = 34754.4 meters
Now, we will divide this number in meters by 331. So, 34754.4 / 331 = 104.998
And what will the unit be? Seconds will be the unit for time here so 104.998 seconds.
what is force ?write its effects.
Answer:A force is a push or pull upon an object resulting from the object's interaction with another object.
A force acting on an object causes the object to change its shape or size, to start moving, to stop moving, to accelerate or decelerate
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1) Burning toast physical or chemical
2) Cooking eggs: physical or chemical
3) Melting butter: physical or chemical
4) Removing the pulp (solid) from the orange juice using a juice strainer.: physical or chemical
5) Cutting the toast with a knife: physical or chemical
6) Digesting the food: physical or chemical
Come up with 2 examples of derived units from everyday life.
Answer:
answer
Explanation:
Area : Square Meters,
Volume : Cubic Meters,
Density : Kilograms per Meter Cube,
Velocity : Meters per Second Squared,
Force : Newtons (Mass multiplied by Acceleration or Mass multiplied by Displacement divided by Time squared)…..
What is the control in the experiment?
Answer:
C. the amount of drug x given to mice
What is the approximate mass of one electron?
Answer:
9.1093837015 × 10^−31 kg
Very small mass
Freezing water cracking limestone
a
Chemical Change
b
Physical Change
Answer:
Freezing water and cracking limestone are physical changes.
what is the concentration of hydrogen ion, H+, present in a water sample if 100. ml of the sample requires 7.2 ml of 2.5 x 10 -3 M NaOH to be neutralized
Answer: 1.8x10^-4 M H+
Explanation: The number of moles of NaOH added to the 100 ml soultion will be equal to the number of moles of H+ present in that solution.
Moles NaOH in 7.2 ml of 2.5x10^-3 M NaOH
(2.5x10^-3 M NaOH) is the same as 2.5x10^-3 moles NaOH/liter
(2.5x10^-3 moles NaOH/liter)*(7.2 ml)*(1 liter/1000ml) = 1.8x10^-4 moles NaOH used to titrate 100 ml of the acid. That means there was 1.8x10^-4 moles of H^+ in 100 ml.
Concentration of H^+ = (1.8x10^-4 moles H)/0.100 l) = 1.8x10^-4 M H+
(pH of 3.74)
May someone help me with the answer to this question I’ve been stuck on it
Explanation:
No, that would be incorrect
Answer:
There arre two main parts of the atom, the nucleus and the orbital rings. The three subatomic particles are contained in each of these, the proton and neutron together in the nucleus and the electrons orbiting in the rings.
Vapor pressure of any liquid _______. A. increases with increases in temperature B. increases with decreases in temperature C. is not affected by changes in temperature D. increases with increases in volume of the liquid E. None of the Above
Answer:
increase with increases in temperature
Explanation:
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If you burn a citronella candle near your picnic will it keep mosquitoes away
Answer:
Thanks!!!
Explanation:
Answer:
true
Explanation:
In your conversion from Milli- to Centi- units, would you move the decimal point to the left or the right?
Answer:
one unit to the left
Explanation:
cm are 10 times mm, so to convert you have to divide by ten
Examples
100 mm = 10,0 cm
0.50 mm = 0.05 cm
Give an example of a non-biological chemical reaction that involves carbon. Name the process that converts a solid compound into a gas.
Answer: The combustion of methane (CH4) with O2.
Explanation: This is a chemical reaction involving carbon:
CH4 + 2O2 = CO2 + 2H2O
Describe the color change that would be observed in water in left hand beaker
Answer:
is there supposed to be a photo with this?
Explanation:
