Answer:
Melting is an example of physical change.
Explanation:
What is 3780 cal to kJ
Answer:
15815.52 kJ
Explanation:
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 %
https://brainly.com/question/14595258
if you are asked to help the laboratory assistant in separating the mixture which method will you see?
Answer:
use secondary data. the normal method to use
will mark brainliest if correct
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 :-)
How many moles of magnesium bromide are formed when 3.0 moles of magnesium reacts with 2.0 moles of bromine?
Mg+Br2 -> MgBr2
Answer:
Explanation:
Hello there, I think this is a limiting agent question.
When 3 moles of Mg is reacted with 2 moles of Br2, because of ratio, we just need 1.5 moles of Br2, so Mg is a limiting agent.
So 3 moles of Mg will make 3 moles of MgBr
Answer:
Use the given functions to set up and simplify
Mg+Br2→MgBr⋅2.
3=
2=
Mg+Br2→gBr⋅2=r2B+gM→MgBr⋅2
Explanation:
SORRY IF I AM WRONG HAVE A BLESS DAY :D
A decrease in temperature reduces the volume of gas
a
Chemical Change
b
Physical Change
Answer:
Chemical change.
Hope this helps you.
Someone plz help me giving brainliest m
Answer:
C
Explanation:
it would be the best action because questions are important when looking at designs/creating them.
Can lead ii carbonate conduct electricity? Explain your answer
Solid Lead II carbonate can not conduct electricity because it is insoluble in water.
First of all, we must establish the fact that ionic solids conduct electricity in solution because they can be broken up into ions in solution.
In the solid state, they do not conduct electricity because the ions are strongly bound by electrostatic forces.
However, if an ionic substance is insoluble in water, its ions are not available to conduct electricity since ions are the charge carrier in solution. As a result of this, such a substance will not conduct electricity.
Since Lead II carbonate is insoluble in water, its ions are not available hence the substance does not conduct electricity.
Learn more: https://brainly.com/question/14077687
Jane and Jack have a bicycling competition Jane rides a constant speed of 12 miles per hour while Jack rides at a constant speed of 330 feet per minute. How fast are Jane and Jack going in meters per second? Who finishes first? Show your factor-label method work. There are 5280 feet in one mile. There are 3.281 feet in one meter
Answer:
Explanation:
I don't know how you want the conversion done. I use dimensional analysis.
Jane
12 miles / hour [1.6 km/1 mile][1000 m/1 km][1 hour / 3600 sec]
12 * [1.6 * 3600 / 1000 m/s] = 69.12 m/s
5.33 m/s This answer is a bit shorter than using 5280 feet.
Using 5280 feet
12 miles / hour [5280 ft/1 mile] [1 m/3.281 feet] * [1 hr/3600 sec]
12 * 5280 / (3.281 * 3600)
12 *. 4470
5.36
Jack
330 feet / minute [ 1 meter / 3.281 feet] [1 minute / 60 seconds]
330 * 1/(3.281 * 60)
330 * 1/(196.86)
1.676 m/s
She's going faster than he is, no matter which method is used to do the calculation
A brick has a mass of 100 G and a volume of 25CM3 what is the density of the brick
Answer:
[tex]\boxed {\boxed {\sf 4 \ g/cm^3}}[/tex]
Explanation:
We are asked to find the density of a brick. Density is a substance's mass per unit volume. The formula for calculating density is as follows.
[tex]\rho= \frac{m}{v}[/tex]
The mass of the brick is 100 grams and the volume is 25 cubic centimeters.
m= 100 g v= 25 cm³Substitute the values into the formula.
[tex]\rho= \frac{ 100 \ g}{25 \ cm^3}[/tex]
Divide.
[tex]\rho=4 \ g/cm^3[/tex]
The density of the brick is 4 grams per cubic centimeter.
Please help me with this chemistry
Answer:
D=1.56g/mL
Explanation:
Density=m/v
D=14.06g/(24mL-15mL)
D=14.06g/9mL
D=1.56g/mL
Why is copper sulfate a compound and diamond an element?
Answer:
Copper(II) sulfate is the chemical compound with the formula CuSO4. This salt exists as a series of compounds that differ in their degree of hydration. The anhydrous form is a pale green or gray-white powder, whereas the pentahydrate (CuSO4·5H2O), the most commonly encountered salt, is bright blue.
Explanation:
Answer:
Copper sulfate is the compound with the formula CuSO4. This salt exists as a series of compounds that differ in their degree of hydration. The anhydrous form is a pale green or gray-white powder, whereas the pentahydrate (CuSO4·5H2O), the most commonly encountered salt, is bright blue.Yes, Diamond is called as an element because it is a crystalline form of a single element i.e., carbon. The structure of Diamond is cubic type, in which one carbon atom is tetrahedrally bonded to four other carbon atoms. This tetrahedral structure is extended in all three directions.Explanation:
I hope U like my answer and my answer helped U....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.
A researcher wants to conduct an experiment to see how the amount of breakfast a student eats
affects their performance in school. He makes 2 groups, one group consumes 300 calories in
the morning while the second group does not eat breakfast at all. After 2 weeks he compares
the students test scores and every student takes the same tests. Identify the following:
a. Control Group:
b. Independent Variable:
c. Dependent Variable:
The control group are the students who eat no breakfast. The independent variable is the consumption of breakfast. The dependent variable is the performance of students in school.
In an experiment, the control group is the group that did not receive the treatment. The treatment in this case is the consumption of breakfast. Hence the group that did not consume breakfast is the control group.
The independent variable is the variable that is being manipulated and its effect evaluated. The manipulated variable here is consumption of food.
The dependent variable is the variable that is being measured. In this case, it is the performance of students at school.
Learn more; https://brainly.com/question/967776
i know that one of them is multiple choice but i’m not sure which one it is.
Explanation:
1. neutrons
2. protons
3. protons and neutrons
4. neutrons
5. electrons
I'm not sure with 1 and 4, sorry :<
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.
Is Cl2 chlorine, dichlorine or dichloride?
Answer:
Cl² is dichlorine
Explanation:
.mark me as brainliest ❤️
Use you observation to determine which polymorph is in the customer’s returned chocolate sample.
Answer:
Cocoa butter, the fat in chocolate, can crystallize in any one of 6 different forms (polymorphs, as they are called). Unfortunately, only one of these, the beta crystal (or Form V), hardens into the firm, shiny chocolate that cooks want. Form VI is also a stable hard crystal, but only small amounts of it form from the good beta (Form V) crystals upon lengthy standing. When you buy commercial chocolate it is in the form of beta crystals.
When you melt chocolate and get it above 94° F, you melt these much desired beta crystals and other types of crystals can set up. If you simply let melted chocolate cool, it will set up in a dull, soft, splotchy, disgusting-looking form. Even the taste is different. Fine chocolate has a snap when you break it and a totally different mouthfeel from the other cocoa butter forms.
Answer:
When you melt chocolate and get it above 94° F, you melt these much desired beta crystals and other types of crystals can set up. If you simply let melted chocolate cool, it will set up in a dull, soft, splotchy, disgusting-looking form. Even the taste is different. Fine chocolate has a snap when you break it and a totally different mouthfeel from the other cocoa butter forms.
Explanation:
hope it's help you......!!!!!!!
#rishu
gots another for you guys thanks inn advance
Answer:
c. the center of curvature of the two sides of the lens
ANSWER QUICK PLEASE!!!! 25 POINTS
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.
Learn more: https://brainly.com/question/15946045
Which of the following statements is not true about ecosystems?
a. A healthy ecosystem can support an unlimited number of life forms.
b. Predators play a role in balancing the earth's ecosystems.
c. People's activities can improve the health of an ecosystem.
d. The parts of an ecosystem depend on each other.
Answer:
A
Explanation:
though an ecosystem can support life forms,when they become over populated or unlimited there will be competition for food,Shelta and other basic necessities which will lead to many of these life forms dying
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:
please mark me brainleast
Magnesium occurs naturally in only three isotopes. ^24 Mg has an isotopic mass of 23.9850 amu and an abundance of 78.99%. ^25 Mg has an isotopic mass of 24.9858 amu and an abundance of 10.00%. Find the mass number of the last isotope of magnesium.
Can someone please explain how to solve this? *done mine the notes*
Answer:
25,98 amu and 11.01% abundance
Explanation:
1. Find the missing abundance
100 - 78.99 - 10 = 11.01 %
2. Using each mass and abundance and the periodic table for the Mg amu
And let Isotope = Mg
23.9850(78.99%) + 24.9858(10%) + Mg(11.01%) = 24.305 (100%)
Solve for Mg
Mg = 25,98
When you leave a wine exposed to the air, the ethanol in it reacts to form what?
Answer:
(ethanol) into acetic acid or vinegar. When wine is exposed to the air, Oxygen in the air interacts with the wine. The wine changes colour and turns both white and red wines brown.
Explanation:
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:
cuantos gramos de soluto y solvente tendra 127 gramos de solición cuya concentración es 14% m/m ayuda para resolverlo
banetshegtsjegsgeheb
What makes an atom radioactive?
Answer:
The unstable nucleus of radioactive atoms emit radiation.
Explanation:
When the atoms of an element have extra neutrons or protons it creates extra energy in the nucleus and causes the atom to become unbalanced and unstable, or radioactive.
(https://www.epa.gov/radtown/radtown-radioactive-atom-activity-4-atomic-stability)
Answer:
When the atoms of an element have extra neutrons or protons it creates extra energy in the nucleus and causes the atom to become unbalanced or unstable. Whether radioactive elements can become stable and if so, how. The unstable nucleus of radioactive atoms emit radiation. ... This process is called radioactive decay.
Explanation:
What is the best definition of
molecule?
A. A molecule is an atom that cannot be broken
down.
B. A molecule is a positively charged partide.
C. A molecule is the smallest part of a substance
that is still that substance
Answer:
C
Explanation:
A molecule is a smallest particle of a substance that has all of the physical and chemical properties of that substance. or
Molecules are two or more atoms chemically joined together.
A gas has a volume of 4.25 m3 at a temperature of 95.0°C and a pressure of 1.05 atm. What temperature will the gas have at a pressure of 1.58 atm and a volume of 2.46 m3
Answer:
[tex]\boxed {\boxed {\sf 82.7 \textdegree C}}[/tex]
Explanation:
We are asked to find the temperature of a gas given a change in pressure and volume. We will use the Combined Gas Law, which combines 3 gas laws: Boyle's, Charles's, and Gay-Lussac's.
[tex]\frac {P_1V_1}{T_1}=\frac{P_2V_2}{T_2}[/tex]
Initially, the gas has a pressure of 1.05 atmospheres, a volume of 4.25 cubic meters, and a temperature of 95.0 degrees Celsius.
[tex]\frac {1.05 \ atm * 4.25 \ m^3}{95.0 \textdegree C}= \frac{P_2V_2}{T_2}[/tex]
Then, the pressure increases to 1.58 atmospheres and the volume decreases to 2.46 cubic meters.
[tex]\frac {1.05 \ atm * 4.25 \ m^3}{95.0 \textdegree C}= \frac{1.58 \ atm *2.46 \ m^3}{T_2}[/tex]
We are solving for the new temperature, so we must isolate the variable T₂. Cross multiply. Multiply the first numerator by the second denominator, then multiply the first denominator by the second numerator.
[tex](1.05 \ atm * 4.25 \ m^3) * T_2 = (95.0 \textdegree C)*(1.58 \ atm * 2.46 \ m^3)[/tex]
Now the variable is being multiplied by (1.05 atm * 4.25 m³). The inverse operation of multiplication is division, so we divide both sides by this value.
[tex]\frac {(1.05 \ atm * 4.25 \ m^3) * T_2}{(1.05 \ atm * 4.25 \ m^3)} = \frac{(95.0 \textdegree C)*(1.58 \ atm * 2.46 \ m^3)}{(1.05 \ atm * 4.25 \ m^3)}[/tex]
[tex]T_2=\frac{(95.0 \textdegree C)*(1.58 \ atm * 2.46 \ m^3)}{(1.05 \ atm * 4.25 \ m^3)}[/tex]
The units of atmospheres and cubic meters cancel.
[tex]T_2=\frac{(95.0 \textdegree C)*(1.58* 2.46 )}{(1.05 * 4.25 )}[/tex]
Solve inside the parentheses.
[tex]T_2= \frac{(95.0 \textdegree C)*3.8868}{4.4625}[/tex]
[tex]T_2= \frac{369.246}{4.4625} \textdegree C}[/tex]
[tex]T_2 = 82.74420168 \textdegree C[/tex]
The original values of volume, temperature, and pressure all have 3 significant figures, so our answer must have the same. For the number we calculated, that is the tenths place. The 4 in the hundredth place to the right tells us to leave the 7 in the tenths place.
[tex]T_2 \approx 82.7 \textdegree C[/tex]
The temperature is approximately 82.7 degrees Celsius.
briefly explain how to separate a mixture of water, kerosene, sawdust and nahso4?
Answer:
Use filtration method lol.
