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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Which two elements have the same number of energy levels with electrons in them?(1 point)
A_ krypton and neon
B_ boron and oxygen
C_ lithium and francium
D_ neon and sodium
Its B) Boron and Oxygen
The correct answer is B.
boron and oxygen have the same number of energy levels with electrons in them.
The energy level of an element is the region around the nucleus where its electron is likely to be, this corresponds to the period of the element in the periodic table.
Elements found in period 1, have one energy level.
Elements found in period 2, have two energy level.
Examples of elements found in period 2 include:
lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, and neonIn the given options, only option B contains two elements with 2 energy level.
Thus, boron and oxygen have the same number of energy levels with electrons in them.
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Behind your house, there's a gorgeous pond filled with frogs. You notice that the frogs behind Mr. Archer's house often have three legs. You start wondering if the fertilizer that Mr. Archer uses for his lawn is causing the deformities in the frogs. You collect 10 frogs and put the special fertilizer in their container (Group A). You put another 10 frogs and place them in a different container with just water (Group B). A week later, 7 out of 10 of the frogs in group A grew only three legs. The frogs in group B grew four legs.
What was the control group?
Answer:
Group B is the control group
Explanation:
In an experiment, a control group is the standard to which comparisons are made in an experiment.
If a sample of water has a mass of 200g and the final solution has a mass of 230g, how much solute dissolved in the water?
WHATS THE FREEZING POINT FOR WATER
Answer:
0 degrees Celcius and 32 degrees fahrenheit
Explanation:
in which sell duplet rule is applied, why?
Answer:
its in explanationExplanation:
the tendency for items have 2 electrons in their outermost shell by interacting with others items through electron sharing or transfer is known as duplet rule. if an atom has 2 electrons in it's outermost shell then it is called duplet rule and if a 8 electrons in it's outermost shell than it is called octet rule .
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)…..
Solid solid soluton example
Explanation:
rice and rice coatssalt and sugarsand and mudwheat flour and corn flourHELP! Fill in the blanks:
The net charge of an atom is equal to the difference between the_____
in the atom's nucleus and the_____
Answer:
I don't know
Explanation:
is today your test
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
La temperatura más baja registrada en EEUU fue de - 70 °F (en Roger Pass montana). Exprese esta temperatura en °C
(Porfavor ayudenme)
Answer:
[tex]thank \: yo[/tex]
Which of the following are considered physical properties of a substance?
Color and odor
malleability and hardness
melting and boiling points
all of the above
hi <3
the correct option would be all of the above
hope this helps :)
ok guys! so! im in my first chemistry class and i dont understand what an ion is!! help please! i need a simple breakdown of how to understand chemistry
Explanation:
Review and Study Material Before Going to Class. ...
Take Good Notes. ...
Practice Daily. ...
Take Advantage of Lab Time. ...
Use Flashcards. ...
Use Study Groups. ...
Break Large Tasks Into Smaller Ones.
reading a variety of chemistry books
Answer:
An ion is an atom or molecule that carries an electric charge.
Ions are identified by the use of a superscript to show the sign and size of their electric charge.
Negatively charged ions are called anions, and positively charged ions are called cations.
Explanation:
An atom is the smallest unit of ordinary matter that forms a chemical element. Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms. Atoms are extremely small, typically around 100 picometers across.
WILL MARK BRAINLEST IF CORRECT!
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
Classify vodka (composed of 50% water and 50% alcohol).
Answer:
Liquor
Explanation:
Can someone plz help me? Plzz giving brainliest!
(Plz chose 3 questions)
Answer:
Facts: A D and maybe C I think you are intended to say C
Explanation:
A is certainly not an opinion. It is either true, or it is not. I think it is intended as a fact.
B is an opinion (which I think is true)
C is kind of iffy. It might be true and it might be an opinion. In looking it up, it is factually incorrect. Cats are related to wildcats in the middle east.
D is also iffy. They can just eat disease free rodents. I'd classify it as more opinion than fact.
E. definitely an opinion.
Câu 3: Nêu phương pháp hóa học nhận biết các dung dịch không màu sau: (a) HCI, NaOH, H2SO,, NaCl. (b) HNO3. KOH, BaCl. Ca(OH)2. Ba(NO3)2 (c) MgCl2, KCl, CuCl2, FeCl3, FeCl2 (chỉ dùng một thuốc thử). (d) Na2CO3, BaCl2, NaNO3 (chỉ dùng một thuốc thử)
Answer:
uvo 8hih8hjfiuwubosbwbhp0heg
Helppppp….. is this right?
Answer:
Yes, it is correct.
Explanation:
400 cm = 4 m
40 m = 40 m
0.4 km = 400m
Therefore, 400 cm < 40 m < 0.4 km
Answer:
Explanation:
400 centimeter....... smallest
0.4 kilometer .............. middlest
40 meter..................... greatest
i got the total but can’t get these ???
Answer:
Volume of heptane in cylinder = 51.2mL
Volume of water = 33mL
Explanation:
Density(g/mL) = mass/ Volume
》Volume = mass/ Density
Please prompt me if I'm wrong in my workings. Hope this helped.
What is the approximate mass of one electron?
Answer:
9.1093837015 × 10^−31 kg
Very small mass
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.
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Which of the following are decomposition reactions?
A. CH4 (9) +202 (9) - CO2 (g) + 2H20 (9)
B. N2 (9) + 3H2 (9) ► 2NH3 (9)
C. CaCO3 (s) - Cao (s) + CO2 (9)
D. 2H20 (1) ► 2H2 (9) + O2 (9)
Answer:
C and D
Explanation:
A reaction is said to be decomposed, if the reactant is broken down to liberate single element.
What are the answers to these?
Answer:
1)physical change
Explanation:
2)chemical change
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
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
Which of these answers describes a scientific law?
(Pls)
Answer:
big ablsolty long pp
Explanation:
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Which type of bond and how many bonds would occur as carbon dioxide (CO2) is formed from carbon in Group IVA and oxygen in Group VIA?
three metallic bonds
two ionic bonds
four covalent bonds
one covalent bond
Four covalent bonds are formed as carbon dioxide (CO2) is formed from carbon in Group IVA and oxygen in Group VIA.
The periodic table is composed of eighteen groups and eight periods. The common thread that holds all the elements in a group is that they all have the same number of valence electrons in their atoms. The elements in the same period all have the same highest energy level.
Oxygen in group Group VIA has six valence electrons while carbon in group Group IVA has four valence electrons. Hence, the chemical bond in carbon dioxide CO2 must contain four covalent bonds as shown in the image attached to this answer.
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Answer:
Four Covalent bonds
Explanation:
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.
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.
Second ionization energies are always _____ than first ionization energies because the remaining electrons are attracted _____ strongly as the positive charge on the ion increases. A large jump in ionization energies is always observed after the _____ electrons have been removed.
