CHEM FINAL PLEASE HELP
On a field trip at the UW Marine Biology Center, Destiny learns that mutiple salt compounds exist in the ocean. While most of the salt compounds are NaCl (sodium chloride), other similar elements form salts in the water. Using the periodic table as a reference, which elements could bond to form a compound most like NaCl?
Question 3 options:
Hydrogen (H) and Oxygen (O)
Potassium (K) and Fluorine (F)
Magnesium (Mg) and Iodine (I)
Lithium (Li) and Sulfur (S)
Answer:
Potassium (K) and Fluorine (F)
Explanation:
A salt is formed with a metal and non-metal element from the periodic table of elements. if you look at the online ptable.com the upper right hand corner of each element shows the valence electrons for each element, and how many are in each shell for that element. Fluorine (F) has 7 valence electrons in its outer most shell, which means there is room for 1 more electron since the second shell can hold a max of 8. Potassium(K) has 1 electron in its outer most shell- which means is can fill in the 1 space available that fluorine has in its outer most shell. Since Potassium(K) is a metal and Fluorine(F) is a non-metal they can form an ionic compound, salt.
how many atoms are in FeS2
Thin Iron metal will burn in oxygen to form iron (III) oxide. Write a balanced equation for this synthesis reaction. Label the limiting and excess reactants? How much mass of the Iron (III) oxide will form from 10.0 grams of each of the reactants? What is amount of the excess reagent will remain at the completion of this reaction? Show your work.
Answer:
14.25 g of Fe2O3
33.26 g of Fe2O3
0.045 moles of excess reagent.
Explanation:
The equation for the reaction is shown below, remember that noting the correct chemical reaction equation is the first step towards solving the problem.
4Fe (s) + 3O2 (g) ==> 2 Fe2O3 (s)
Since the oxygen is abundant in air, oxygen is the reactant in excess while the iron is the limiting reactant. Remember that only a thin iron metal burns according to the question.
To double check our assumption above, the reactant that gives the least mass of product is the limiting reactant.
Using iron;
If 224 g of iron yields 319.38 g of Fe2O3
10g of iron will yield 10 × 319.38/224 = 14.25 g of Fe2O3
Using oxygen
96 g of oxygen yields 319.38 g of Fe2O3
10 g of oxygen will yield 10 × 319.38/96 = 33.26 g of Fe2O3
Since iron is the limiting reagent, number of moles in 10g of iron = 10g/56gmol-1 = 0.18 moles
From the reaction equation
4 moles of iron reacts with 3 moles of oxygen
0.18 moles of iron will react with 0.18 ×3/4 = 0.135 moles of oxygen
Amount of excess reagent remaining; 0.18- 0.135 = 0.045 moles of excess reagent.
Please help.. I am begging
A wave's frequency refers to _____________. *
the number of wavelengths passing by a given point in a period of time
the heigh of a wave as it passes a given point
the length of a wave
the strength of a wave
Answer:
The length of a wavelength.
Explanation:
"A wave frequency refers to..." The length of a wavelength, or how long the wavelength is.
Hope this helped :)
4. How many grams of ammonium carbonate are needed to decompose in order to produce
6.52g of carbon dioxide? Ammonium oxide is the other product.
(NH4)2(CO,) – (NH4)2O + CO2
Answer:
14.23g of (NH4)2CO3
Explanation:
We'll begin by writing the balanced equation for the reaction.
(NH4)2CO3 –> (NH4)2O + CO2
Next,, we shall determine the mass of (NH4)2CO3 that decomposed and the mass of CO2 produced from the balanced equation. This is illustrated below:
Molar mass of (NH4)2CO3 = 2[14+(4x1)] + 12 + (16x3)
= 2[14 +4] + 12 + 48
= 2[18] + 60 = 96g/mol
Mass of (NH4)2CO3 from the balanced equation = 1 x 96 = 96g
Molar mass of CO2 = 12 + (2x16) = 44g/mol
Mass of CO2 from the balanced equation = 1 x 44 = 44g.
Summary:
From the balanced equation above,
96g of (NH4)2CO3 decomposed to produce 44g of CO2.
Finally, we can determine the mass of (NH4)2CO3 that decomposed to produce 6.52g of CO2 as follow:
From the balanced equation above,
96g of (NH4)2CO3 decomposed to produce 44g of CO2.
Therefore, Xg of (NH4)2CO3 will decompose to produce 6.52g of CO2 i.e
Xg of (NH4)2CO3 = (96 x 6.52)/44
Xg of (NH4)2CO3 = 14.23g
Therefore, 14.23g of (NH4)2CO3 is needed to produce 6.52g of CO2.
Calculate the answer. Express it in scientific notation and include the correct number of significant figures. (12 x 10^4 ) x (5 x 10^-2 ) = _____
Answer:
60 x 10^6
Explanation:
12 x 5 = 60
add the exponents 4+2 so 10^6
60 x 10^6 is the answer
What is the formula for this ionic compound and tha name ?
Explanation:
K3P = Potassium phosphide
How many grams of calcium chloride will be needed to make 750 mL of a 0.100 M CaCl2 solution?
Answer:
Molarity or molar concentration is the number of moles of solute that can be dissolved in 1 L of a solution.
Molarity = Number of solute (in moles) / Volume of solution (in liters), or
C = n / V
According to the question,
V = 750 ml and C = 0.100 M
For this, let us convert ml into liters
We know 1 L = 1000 ml
Hence, 750 ml = (750/1000) L = 0.75 L
So, V = 0.75 L
We know that C = n / V
So, n = C x V
n = 0.100 x 0.75 = 0.075
n is the number of moles of solute.
Hence, number of moles of CaCl2 = 0.075 moles
That means there are 0.075 moles of CaCl2 in 750 ml of solution.
In order to determine the mass of CaCl2 in grams, we need to know the molar mass of CaCl2.
For this, we need to find out the atomic mass of each atom (by referring the periodic table).
CaCl2 has 1 Ca atom and 2 Cl atoms.
Atomic mass of
Ca = 40.08 g
Cl = 35.45, Cl2 means 2 x 35.45 = 70.90 g
Adding these values, we get mass of CaCl2 in grams.
Hence, mass of CaCl2 = 40.08 + 70.90 = 110.98 g
Thus, 1 mole of CaCl2 weighs 110.98 g.
Hence, 0.075 moles of CaCl2 will weigh
0.075 x 110.98 = 8.3235 g, rounded to 8.32 g
So restating the question, we can say that 8.32 grams of CaCl2 will be needed to make 750 ml of a 0.100 M CaCl2 solution.
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Why would an unstable radioactive isotope (nuclide) emit a beta particle (high energy electron)?
A)It has too many neutrons
B)It has too many protons
C)It has too many electrons
D)It has too few electrons
Answer:
A)It has too many neutrons
Explanation:
Electrons are emitted from the nucleus when a neutron is converted to a proton, an electron and a neutrino. This process is popularly known as beta emission. It reduces the neutron-proton ratio of a nuclide. The neutrino is a particle of zero mass and zero charge that carries off the excess energy and balances spins.
The loss of an electron from the nucleus occurs when there are too many neutrons in the nucleus. The process of beta emission usually reduces the number of neutrons in an atom thereby decreasing the neutron-proton ratio.
Which periodic group has the
smallest atomic radius?
Answer:
Helium
Explanation:
Atomic radii vary in a predictable manner across the periodic table. As can be seen in the figures below, the atomic radius increases from top to bottom in a group and decreases from left to right over a period of time. Helium is therefore the smallest element, and francium is the largest.
In the periodic table, the atomic radius increases from top to bottom in a group, and decreases from left to right across a period. Therefore, helium is the smallest element.
What is atomic radius ?The term atomic radius is defined as the radius of an atom. This distance between an atom's nucleus and outer electron shell is an atomic radius.
The atomic radius is half the distance between the nuclei of two identical atoms that are bonded together. Atoms' atomic radius decreases from left to right across a period. Atoms' atomic radius increases from top to bottom within a group.
Atomic radius varies predictably across the periodic table. The atomic radius increases from top to bottom in a group and decreases from left to over time.
As a result, helium is the smallest element and francium is the largest.
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In what direction does heat flow?
A. Heat flows back and forth between objects.
B. Heat flows from an object of higher temperature to an object of
lower temperature.
C. Heat flows from an object of lower temperature to an object of
higher temperature,
D. Heat flows only if objects are at the same temperature,
The direction in which heat flows in a system is that: B. heat flows from an object of higher temperature to an object of lower temperature.
What is heat?Heat is also referred to as thermal energy and it can be defined as a form of energy that is transferred from one object (body) to another, especially due to a difference in temperature.
This ultimately implies that, heat is primarily transferred between objects that have different degrees of temperature during the process of heat conduction.
According to the kinetic-molecular theory, heat is generally transferred from a hotter object with higher temperature to a cooler object with lower temperature.
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The major cause of a warmer planet
comes from?
Answer:
It is caused by increased concentrations of greenhouse gases in the atmosphere, mainly from human activities such as burning fossil fuels, deforestation and farming.
Explanation:
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The freezing point of pure water at sea level is 0°C. What is that in kelvins?
O A. 25 K
O B. 273 K
O C. -273 K
O D.OK
Answer:b
Explanation:
The Kelvin degree is the same size as the Celsius degree; hence the two reference temperatures for Celsius, the freezing point of water (0°C), and the boiling point of water (100°C), correspond to 273.15°K and 373.15°K, respectively.
Oxidation numbers are written with the positive or negative sign _____ the number. after before over under
Answer:
The answer to this question is over
Oxidation numbers are written with the positive or negative sign over the number.
What is oxidation number?Oxidation number of any element gives idea about the exchangeable number of electrons from the outermost shell of that element.
If electrons are losing from the valence shell then the element will show positive oxidation number and if electrons are gained to the valence shell then element will show negative oxidation state.
Elements with oxidation state will be shown as Mg²⁺, O²⁻ means oxidation state is expressed at the top or over of the symbol of element.
Hence oxidation states are written over the numbers.
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What is the molarity of a solution that contains 0.75 moles of solute in a 1.5 L of solution? Show your work.
Answer:
0.5 m
Explanation:
M= .75 /1.5 = 0.5 mol
Please help will give brainliest
Which of the following statements are correct regarding the binding energy?
Answer:
You really should have put the options so the other person could have helped then. Luckily, I had this exact same question on a lesson in Chemistry.
- Binding energy is equivalent to the mass that is converted to energy to hold the nucleus together.
- Binding energy is the minimum energy required to split the nucleus.
- Binding energy per nucleon is the ratio of the binding energy to the number of nucleons.
Oil and fat containing food items are flushed with nitrogen. Why?
Answer:
oil and fat containing food terms items flushed with nitrogen because nitrogen acts as an antioxidant and it prevents them from being oxidised.
Explanation:
Nitrogen is an inert gas that is flushed in food items as it does not react with food items and removes all the oxygen present in food. Oxygen present in food products is then rancid by the presence of oils and fats. Nitrogen is chemically non-reactive with oils and fats and therefore preserves oily food products.
hope this helped!
Answer:
Nitrogen is used to flush the foods because it does not interact with the foods and the oils and fats within them.
Explanation:
Nitrogen serves as an antioxidant to remove oxygen from the food and prevent it from being oxidized. Typically, it is also used to keep the fats and oils from binding with it and ruining the integrity and structure of the food.
does anyone know the answer???
In a lab, 33 g of potassium chloride is formed from 60.0 g of potassium chlorate decomposing. Calculate the theoretical yield and percent yield for this experiment.
Answer: The theoretical yield and percent yield for this experiment are 40 g and 82% respectively.
Explanation:
[tex]2KClO_3\rightarrow 2KCl+3O_2[/tex]
According to avogadro's law, 1 mole of every substance weighs equal to the molecular mass and contains avogadro's number [tex](6.023\times 10^{23})[/tex] of particles.
To calculate the moles:
[tex]\text{Moles of potassium chloride}=\frac{\text{Mass of potassium chloride}}{\text{Molar mass of potassium chloride}}=\frac{33g}{74.5g/mole}=0.44moles[/tex]
[tex]\text{Moles of potassium chlorate}=\frac{\text{Mass of potassium chlorate}}{\text{Molar mass of potassium chlorate}}=\frac{66g}{122.5g/mole}=0.54moles[/tex]
According to stochiometry:
2 moles of [tex]KClO_3[/tex] produce = 2 moles of [tex]KCl[/tex]
0.54 moles of [tex]KClO_3[/tex] should produce = [tex]\frac{2}{2}\times 0.54=0.54moles[/tex] of [tex]KCl[/tex]
Thus theoretical yield is [tex]moles\times {\text {Molar mass}}=0.54mol\times 74.5g/mol=40g[/tex]
But Experimental yield is 33 g.
[tex]{\text {percentage yield}}=\frac{\text {Experimental yield}}{\text {Theoretical yield}}\times 100\%[/tex]
[tex]{\text {percentage yield}}=\frac{33g}{40g}\times 100\%=82\%[/tex]
The theoretical yield and percent yield for this experiment are 40 g and 82% respectively.
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7th-grade science.
What does the number, such as 98.7 FM, of a radio station represent?
Answer:
The number, such as 98.7 FM, of a radio station represents:
the frequency in which is transmitted the radio signal.Explanation:
The radio FM is the modulated frequency, which means that all the information is sent by just a signal, with different frequencies which difference them, the radio FM use the frequencies from 88 MHz until 108 Mhz (MHz is a measuring unit for the frequency), with a minimal space among them of 0.2 MHz, this last means that you could find a signal in 88.0 MHz, and the next should be 88.2 MHz, next 88.4 MHz and so (at least, regularly the space between two frequencies is more than 0.2 MHz).
Which element has the lowest ionization energy?
A partial periodic table. 18 columns are shown; all columns align at the bottom. The first column is 6 entries, headed 1 and 1 A. Entries are upper H, upper L i, upper N a, upper K, upper R b, and upper C s. The second column is 5 entries, headed 2 and 2 A. Entries are upper B e, upper M g, upper C a, upper S r, and upper B a. 7 columns of 3 entries each follow; all entries are blank. The next column is 3 entries also; the first entry is upper N i and the rest are blank. 2 more blank columns of three follow. Five further columns of five entries each follow. The first of these is headed 13 and 3 A; entries are upper B, upper A l, and three blank cells. Next column is labeled 14 and 4 A; entries are upper C, upper S i, upper G e, and two blank cells. Next column is labeled 15 and 5 A; entries are upper N, upper P, and upper A s, with 2 blank cells below. The next column is labeled 16 and 6 A; entries are upper O, upper S, and upper S e followed by 2 blank cells. The next column is labele
argon (Ar)
bromine (Br)
cesium (Cs)
nickel (Ni)
Answer:
Cs
Explanation:
This question is formatted oddly, but I understand the gist of it. Essentially, even if the periodic table is cut off by one row and missing the lanthanides and actinides, basic rules of the table still apply.
Remember the general trend of ionization energy: the farther to the right and the farther up, the higher the ionization energy.
As an example, fluorine is the "t-rex" of the elements because it's so electronegative that it hoards electrons, and that means it's hard to take its electrons away, which gives it a high ionization energy.
Out of the given choices, cesium Cs has the lowest ionization energy because it's so far to the left and so low. You can just nab an electron and it won't even mind too much.
Why not the other answer choices? Bromine is a halogen (so it's on the far right of the table) and it's fairly high up, so its ionization energy is much too high. Argon is a noble gas, so it's so stable that it hates it when someone tries to take an electron away; it has a very high ionization energy. Nickel, likewise, is a transition metal, so it's not the answer either.
Answer:
C
Explanation:
How does pollution affect air resources?
Answer: it gets inside the air and then it infects the air's resourses
Explanation:
Which of these, all of which include earth, most likely contains the most dark matter
Answer: Milky Way Galaxy=b
Explanation:
what is a pattern in nature a.the repeated occurrence of an event b.a set of measurements that's answers a scientific question c.a collection of scientific theories that helps scientist understand the world d.An arrangement of object that are in predictable places
Answer:
its a
Explanation:
Answer:
The repeated occurrence of an event
Explanation:
How many grams of carbon dioxide are formed from 25 moles of octane
Explain in terms of molecular formulas and structural formulas why 2,2-dimethylbutane is an isomer of hexane
Answer:
The answer to your question is given below.
Explanation:
Molecular formula gives the exact amount of each type of element in a molecule. Hence, it gives the formula of the compound.
Structural formula on the other hand shows how the different elements in a molecule of a compound are arranged in space.
Isomerism is a phenomenon whereby two or more compounds have the same molecular formula but different structural patterns. The compounds involved are called isomer.
2,2-dimethylbutane is an isomer of hexane because they both have the same molecular formula but different structural patterns.
Hexane can be rearrange to obtain 2,2-dimethylbutane.
The attached photo shows that 2,2-dimethylbutane and hexane have the same molecular formula i.e C6H14 but their structural arrangement is different. Hence they are called isomers.
Isomerism is a phenomenon whereby two or more compounds have the same molecular formula but different structural patterns. The compounds involved are called isomer.
2,2-dimethylbutane is an isomer of hexane because they both have the same molecular formula but different structural patterns.
Hexane can be rearrange to obtain 2,2-dimethylbutane.
In the attached figures, 2,2-dimethylbutane and hexane have the same molecular formula i.e. C₆H₁₄ but their structural arrangement is different. Therefore, they are called isomers.
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If your weight is 120 pounds
and your mass is 54 kilograms, how would those
values change if you were on the moon? The grav-
itational force on the moon is 1/6 the gravitational
force on Earth.
Explanation:
Weight is 120 pounds and mass is 54 kg
The mass of an object is same everywhere. If we were on the moon, its mass will remain to be 54 kg.
Weight of an object is given by :
[tex]W=m\times g[/tex]
g is acceleration due to gravity on that surface
For moon, it is 1/6 the gravitational force on Earth, g = 1.63 m/s²
1 pound = 4.45 N
It means my weight is 533.78 N
On the surface of Moon is will be :
[tex]W=\dfrac{533.78}{1.63}\\W=327.47\ N[/tex]
The following exothermic reaction is allowed to reach equilibrium. What
happens when the reaction temperature is decreased? (think about what
side heat would be on in an exothermic reaction)
2 H, + 02 → 2H2O
O Favors the forward reaction
O Favors the reverse reaction
O The reaction is still at equilibrium
Mr. Holmes and Mrs. Nogaki are having a good old fashioned Baby Back Ribs BBQ contest and are arguing over who’s BBQ produces less greenhouse gasses. Mrs. Nogaki uses natural gas to power her BBQ and provided the balanced equation to Mr. Holmes as proof of how efficient her grill is.
CH4 + 2O2→CO2 +2H2O
Mrs. Nogaki claims that for every mole of natural gas burned, only 1 mole of CO2 is produced.
Mr. Holmes doesn’t have a prepared balanced equation but knows that the chemical formula of propane is C3H8 and that it is a combustion reaction.
Who is right?
Question 19 options:
Mrs. Nogaki is right because Mr. Holmes’s BBQ produces 2x less CO2 for each mole of fuel burned.
Both are right because in a combustion reaction, CO2 and water are always produced.
Mr. Holmes is right because his BBQ produces less CO2 for each mole of fuel burned than Mrs. Nogaki’s grill.
Mrs. Nogaki is right because Mr. Holmes’s BBQ produces 3x more CO2 for each mole of fuel burned.
Answer:
Mrs. Nogaki is right because Mr. Holmes’s BBQ produces 3x more CO2 for each mole of fuel burned.
Explanation:
Now Mrs. Nogaki has already figured out the chemical combustion reaction behind the operation of her BBQ. It is pertinent to reproduce it here.
CH4(g) + 2O2(g)→CO2(g) +2H2O(g)
She already has this figured out but Mr. Holmes doesn't have any chemical reaction equation to back his claims. Let us help him with the correct combustion equation for propane.
C3H8(g) + 5O2(g) + 3CO2(g) + 4H2O(g)
We can clearly see from the reaction equation that Mr. Holmes BBQ produces three times more carbon IV oxide than Mr. Nogaki's BBQ so Mr. Nogaki was right in her claim after all.
Hence the answer!
