Answers
Answer:
1.
Solid: A, B, and C.
Liquid: D and E.
Gas: F.
2.
Into liquid on warm day (37 °C): D and C.
Into a liquid only when heated slightly: C and E.
From liquid to solid readily when placed into a freezer (0 °C): D.
Explanation:
Hello!
In this case, since the melting point is the temperature at which a substance change from solid to liquid and the boiling point from liquid to gas, we understand that substance at a temperature below the melting point is solid, whereas above are liquid; moreover, below the boiling point they are liquid and above gaseous.
In such a way, we have:
1.
Solid: A, B, and C.
Liquid: D and E.
Gas: F.
2.
Into liquid on warm day (37 °C): D and C.
Into a liquid only when heated slightly: C and E.
From liquid to solid readily when placed into a freezer (0 °C): D.
Best regards!
Related Questions
an orbital is a region in an atom where there is a high probability of finding _________
A) an alpha particle
B) a neutron
C) an electron
D) a positron
Answers
Answer:
its electron
Explanation:
i dont have an explanation but i hope you get it right
pls help asap!!
The surface of earth has many impact craters that have been filled in with sediment. these craters were created by
A. moles
B. dinosaurs
C. people
D. meteorites
Answers
Answer:
D
Explanation:
Craters produced by the collision of a meteorite with the Earth (or another planet or moon) are called impact craters. The high-speed impact of a large meteorite compresses, or forces downward, a wide area of rock. The pressure pulverizes the rock.
A certain liquid X has a normal boiling point of 133.60°C and a boiling point elevation constant Kb= 2.46°C kg mol^-1.Calculate the bolling point of a solution made of 52.2g of benzamide (C7H7NO) dissolved in 350. g of X.
Answers
Answer:
136.63 °C
Explanation:
ΔTb=Tb solution - Tb pure
Where; Tb pure = 133.60°C
molar mass of solute = 121.14 g/mol
number of moles of solute; 52.2g/121.14 g/mol = 0.431 moles
molality = 0.431 moles/350 * 10^-3 = 1.23 molal
Then;
ΔTb = Kb * m * i
Kb = 2.46°C kg mol^-1
m = 1.23 molal
i = 1
ΔTb = 2.46 * 1.23 * 1
ΔTb = 3.03 °C
Hence;
Tb solution = ΔTb + Tb pure
Tb solution = 3.03 °C + 133.60°C
Tb solution = 136.63 °C
what problems occurs if the firework mixture is not pure(they are dirty or contaminated?
Answers
Fireworks cause broad air contamination in a short measure of time
Explanation:
Fireworks cause broad air contamination in a short measure of time, leaving metal particles, hazardous poisons, destructive synthetic compounds and smoke noticeable all around for quite a long time. A portion of the poisons never completely decay or break down, but instead stick around in the earth, harming all they come into contact with
Firework mixture is made up with potassium nitrate and other toxic chemicals. They produce harmful wastes to the atmosphere. If they are contaminated, they make release very dangerous explosives by unwanted reactions.
What are explosives?Explosives are chemicals releasing lot of heat energy to the surrounding upon decomposition. Nitrogen compounds, hydrogen etc are explosive and they will explode in air or water.
Chemicals have to handled carefully and stored as per the conditions based on their chemical and physical properties. Some of them may easily corrode. Some may rapidly reacts with water or air and some may explode in air.
Explosive chemicals causes atmospheric pollution as well as health risk by releasing hazardous chemicals. If they are contaminated then there may occur some unwanted reaction and it will make the risk intense by producing toxic gases.
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what is the correct meaning of the word catapult?
example :
mounting tension between england and the colonies helped catapult washingtons rank in the continental army.
a. hamper
b. improve
c. propel
d. define
Answers
Answer:
A. hamper
Explanation:
i did this question before.
Answer:
Improve
Explanation:
They improved Washington's rank so that he could rise to the top.
Chemical bonds between atoms in molecules such as H2, CH4, NH3, and
many large biological molecules are:
lonic Bonds
Hydrogen Bonds
Covalent Bonds
Metallic Bonds
Answers
Answer:In ionic compounds, electrons are transferred between atoms of different elements to form ions. But this is not the only way that compounds can be formed. Atoms can also make chemical bonds by sharing electrons equally between each other. Such bonds are called covalent bonds. Covalent bonds are formed between two atoms when both have similar tendencies to attract electrons to themselves (i.e., when both atoms have identical or fairly similar ionization energies and electron affinities). For example, two hydrogen atoms bond covalently to form an H2 molecule; each hydrogen atom in the H2 molecule has two electrons stabilizing it, giving each atom the same number of valence electrons as the noble gas He.
Compounds that contain covalent bonds exhibit different physical properties than ionic compounds. Because the attraction between molecules, which are electrically neutral, is weaker than that between electrically charged ions, covalent compounds generally have much lower melting and boiling points than ionic compounds. In fact, many covalent compounds are liquids or gases at room temperature, and, in their solid states, they are typically much softer than ionic solids. Furthermore, whereas ionic compounds are good conductors of electricity when dissolved in water, most covalent compounds are insoluble in water; since they are electrically neutral, they are poor conductors of electricity in any state.
Which of the following subatomic particles gives the nucleus of an atom its mass?
O both protons and neutrons
O electrons only
O neutrons only
O protons only
Answers
25.
Chemical equations should be balanced so that they demonstrate the Law of Conservation of Mass. Which statement about balanced chemical equations is correct?
A
The products must contain the same number and types of atoms as the reactants.
B. The products must contain the same arrangement of atoms as found in the reactants,
C. The products must contain the same number but not the same types of atoms as the reactants.
D. The products must contain the same types but not the same numbers of atoms as the reactants,
Answers
Answer:
a
Explanation:
they have to have the same numbers on each side.
According to the law of conservation of mass, the total mass in the product side is equal to the mass in the reactant side of a reaction. Thus, option A that is The products must contain the same number and same types of atoms as the reactants is correct.
What is mass conservation?Mass conservation is similar to law of energy conservation. That is mass can neither be created nor be destroyed. Thus The total mass in a system is conserved. Therefore,in reaction the mass of product have to be equal to the mass of reactant.
A balanced reaction represent all reactants in their state and in perfect stoichiometry. Hence, each elements have to be equal in number on both side. No new atoms is created here and no atom is lost.Same number and same type will be in both side.
During a chemical reaction, the regrouping of atoms occurs to form the new product. Hence, no new atoms are added . Therefore The products must contain the same number and same types of atoms as the reactants and satisfies the mass conservation.
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Rank the following compounds in order of decreasing boiling point: potassium fluoride (KF), acetylene (C2H2), and formaldehyde (CH2O)
Answers
Answer: [tex]KF[/tex] > [tex]CH_2O[/tex] > [tex]C_2H_2[/tex]
Explanation:
The order of boiling point depends upon the type of interactions present between the molecules.
Potassium fluoride (KF) is an ionic compound and the opposite ions are held together by strong electrostatic forces.
[tex]C_2H_2[/tex] is a covalent compound and the molecules are held together by weak van der Waals' forces.
Formaldehyde is a polar compound due to presence of polar carbonyl group. Hence dipole-dipole force is present between formaldehyde molecules.
Thus the decreasing order of boiling point is:
[tex]KF[/tex] > [tex]CH_2O[/tex] > [tex]C_2H_2[/tex]
3 H2 (g) + N2 (g) 2 NH3 (g)
1.36 liters of hydrogen gas will produce how many grams of NH3 at STP?
Answers
Answer:
Mass = 0.697 g
Explanation:
Given data:
Volume of hydrogen = 1.36 L
Mass of ammonia produced = ?
Temperature = standard = 273.15 K
Pressure = standard = 1 atm
Solution:
Chemical equation:
3H₂ + N₂ → 2NH₃
First of all we will calculate the number of moles of hydrogen:
PV = nRT
R = general gas constant = 0.0821 atm.L/mol.K
1atm ×1.36 L = n × 0.0821 atm.L/mol.K × 273.15 K
1.36 atm.L = n × 22.43 atm.L/mol
n = 1.36 atm.L / 22.43 atm.L/mol
n = 0.061 mol
Now we will compare the moles of hydrogen and ammonia:
H₂ : NH₃
3 : 2
0.061 : 2/3×0.061 = 0.041
Mass of ammonia:
Mass = number of moles × molar mass
Mass = 0.041 mol × 17 g/mol
Mass = 0.697 g
In an atom, the number of protons equals the number of
nuclei
electrons
neutrons
isotopes
Answers
Answer:
Electrons
Explanation:
How do you think the periodic table helps us better understand our world?
Answers
Answer:
The periodic table helps organize all the elements found in the world and tells a great deal of information on each of the elements such as their atomic mass, symbol, atomic number, and more. It even is organized into groups (columns) and periods (rows). The elements in the same group mostly have similar chemical properties. In short, the periodic table is a list of the elements that make up the world around you.
Explanation:
What is the charge of an element with 15 protons, 19 neutrons and 18 electrons?
Answers
Answer:
negative
Explanation:
18 negative
19 neutral
10 positive
there are are more negative
assume you mix 0.71g of chlorine with 1.00g of fluorine in a 258 ml flask at 23 . what is the partial pressure of each gas
Answers
Answer:
See explanation
Explanation:
Number of moles of Cl2 = 0.71g/71g/mol = 0.01 moles
Number of moles = 1.0 g/38g/mol = 0.02 moles
Total = 0.01 + 0.02 = 0.03 moles
From the ideal gas equation;
PV=nRT
P=?
V= 258 ml
n= 0.03 moles
T= 296 K
P= nRT/ V
P= 0.03 × 0.082 × 296/258
P= 0.003 atm
Partial pressure Cl2 = 0.01/0.03 × 0.003 atm = 0.001 atm
Partial pressure = F2 = 0.02/0.03 × 0.003atm = 0.002 atm
A student fails to insert the cuvette into the colorimeter or spectrophotometer correctly. What effect will this have on the measured absorbance
Answers
Answer:
It would cause scattering of light and absorbance measurement is going to be reported as too large
Explanation:
The curvette was not inserted correctly into the spectrometer. The effect that this would have on measured absorbance is that it would cause scattering of light.
Failing to line the curvette correctly would cause light to scatter, the light reaching the photodetector would be less. This less light would then be interpreted as more light being absorbed. This would end up making the absorbance value to be read as too large.
How many moles are in 1.5 x 10^23 atoms of fluorine?
Answers
Answer: 0.125 moles F2
Explanation: 1.5x1023 atoms of F = 0.75x10^23 molecules F2
moles F2 = 0.75x10^23/avogadro number = 0.125 moles
There are 0.25 moles in 1.5 x [tex]10^{23}[/tex] atoms of fluorine.
Given,
How many moles are in one atom?
In one mole we have,
6.02 x [tex]10^{23}[/tex] atoms.
1 mole = 6.02 x [tex]10^{23}[/tex] atoms
Find the number of moles in 1.5 x [tex]10^{23}[/tex] atoms of fluorine.
We have,
1 mole = 6.02 x [tex]10^{23}[/tex] atoms
Multiply 1.5 x [tex]10^{23}[/tex] / 6.02 x [tex]10^{23}[/tex] on both sides
1.5 x [tex]10^{23}[/tex] / 6.02 x [tex]10^{23}[/tex] x 1 mole = 1.5 x [tex]10^{23}[/tex] / 6.02 x [tex]10^{23}[/tex] x 6.02 x [tex]10^{23}[/tex] atoms
1.5/6.02 mole = 1.5 x [tex]10^{23}[/tex] atoms
0.25 moles = 1.5 x [tex]10^{23}[/tex] atoms.
Thus there are 0.25 moles in 1.5 x [tex]10^{23}[/tex] atoms of fluorine.
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The formation of chemical bonds from separated atoms 1. is never spontaneous. 2. increases entropy. 3. is always endothermic. 4. is always exothermic. 5. may be either endothermic or exothermic.
Answers
Answer:
is always exothermic
Explanation:
You see, whether a process is endothermic or exothermic depends on the result of the operation; ΔHreaction= ΔHproducts - ΔHreactants.
If the enthalpy of reactants exceeds that of the products, then the process is exothermic.
We should remember that the energy of isolated atoms is always higher than the energy of the compound formed when the atoms bond together. Hence bond making is an exothermic process.
Energy is used to form bonds and released when they are broken, bond-breaking is considered to be endothermic. Additionally, the creation of bonds is typically an exothermic process. The formation of chemical bonds from separated atoms is exothermic. The correct option is 4.
When bonds are created in the products of exothermic processes, more energy is produced than is required to break the bonds between the reactants. The temperature of the reaction mixture rises as a result of exothermic reactions. Endothermic chemical processes are those that generally absorb (or use) energy.
An attraction between atoms or ions is referred to as a chemical bond. Atoms trade or exchange valence electrons to create bonds.
Thus the correct option is 4.
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What is the relationship between the period number and the number of valence electrons?
Answers
Answer: Across each row, or period, of the periodic table, the number of valence electrons in groups 1–2 and 13–18 increases by one from one element to the next. Within each column, or group, of the table, all the elements have the same number of valence electrons.
Relationship between the period number and the number of valence electrons:
There are total 7 period in a periodic table.Valence electrons can be also determined as electrons in the outermost shell.The number of valence electrons in an atom is reflected by its position in the periodic table of the elements.Across each row, or period, of the periodic table, the number of valence electrons in groups 1-2 and 13-18 increases by one from one element to the next.For example: Group 17 has 7 valence electrons which is one less to the next group number i.e. 18.Within each column, or group, of the table, all the elements have the same number of valence electrons.Learn more:
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Which cause of wildfires is least likely to lead to catastrophic results
O arson
Olightning strike
O controlled burn
O unattended campfire
Answers
The controlled burn cause of wildfires is least likely to lead to catastrophic results. Therefore, option (C) is correct.
What is controlled burning?A controlled burn is a fire set intentionally for purposes of forest management, prairie restoration, farming, or greenhouse gas. A controlled burn refers to the intentional burning of slash, fuels through burn piles.
Controlled burning can be done during the cooler months to reduce fuel buildup and reduce the likelihood of serious hotter fires. Controlled burning enhances the germination of desirable forest trees, and exposes soil mineral layers which expand seedling vitality.
Controlled burning is also useful in agriculture as it is often referred to as slash and burns. It is one component of shifting cultivation, as a section of field preparation for planting called field burning. This technique is utilized to clear the land of any existing crop residue and kill weeds and weed seeds.
Field burning is less expensive but because it forms smoke and air pollutants, its use is not common in agricultural areas.
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Based on your observations from the glowing splint test with oxygen gas, briefly explain why liquid oxygen is a very hazardous substance
Answers
Answer:
liquid oxygen is highly flammable
Explanation:
near any source of heat. liquid oxygen can explode to flames thus being hazardous
Which best explains why male whitetail deer grow antlers but females seldom grow antlers?
Answers
Answer: I'm not sure if you have a selection of choice but I think it's A. Female deer have no need for antlers.
Explanation: I mean they don't.. Even if the Male are older that doesn't stop a female deer from growing antlers.. Just flimsy one's I guess.
In an ecosystem, as the growth of antlers is controlled by genes male male whitetail deer grow antlers but females seldom grow antlers.
What is an ecosystem?Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.
Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.
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What is the mass of 1.33 moles of Ba3(PO4)2?
Choices:
108 g
801 g
659 g
801 mol
Please help :(
Answers
Answer:
801 g
Explanation:
From the question given above, the following data were obtained:
Number of mole of Ba₃(PO₄)₂ = 1.33 moles
Mass of Ba₃(PO₄)₂ =?
Next, we shall determine the molar mass of Ba₃(PO₄)₂. This can be obtained as follow:
Molar mass of Ba₃(PO₄)₂ = (137.3×3) + 2[31 + (4×16)]
= 411.9 + 2[31 + 64]
= 411.9 + 2[95]
= 411.9 + 190
Molar mass of Ba₃(PO₄)₂ = 601.9 g/mol
Finally, we shall determine the mass of Ba₃(PO₄)₂. This can be obtained as follow:
Number of mole of Ba₃(PO₄)₂ = 1.33 moles
Molar mass of Ba₃(PO₄)₂ = 601.9 g/mol
Mass of Ba₃(PO₄)₂ =?
Mole = mass /Molar mass
1.33 = Mass of Ba₃(PO₄)₂ / 601.9
Cross multiply
Mass of Ba₃(PO₄)₂ = 1.33 × 601.9
Mass of Ba₃(PO₄)₂ = 801 g
A scientist wants to make a solution of tribasic sodium phosphate, Na3PO4, for a laboratory experiment. How many grams of Na3PO4 will be needed to produce 725 mL of a solution that has a concentration of Na ions of 1.50 M
Answers
Answer:
178.35g
Explanation:
Molarity of a solution can be calculated using the formula:
Molarity = number of moles ÷ volume
Based on the information provided in this question, molarity (M) of the solution = 1.50 M, volume = 725 mL = 725/1000 = 0.725L, n = ?
1.50 = n / 0.725
n = 1.50 × 0.725
n = 1.0875mol
Molar mass of Na3PO4
23(3) + 31 + 16(4)
= 69 + 31 + 64
= 164g/mol
Mole = mass ÷ molar mass
1.0875 = mass/164
mass = 178.35g
PLZ HELP ME!!!!!! BEING TIMED!!!!!
Answers
Answer:
3 one
Explanation:
Which feature do all adult echinoderms have?
O moveable spine
O muscular foot
O mantle
O endoskeleton
Answers
Answer:
endoskeleton i think
Explanation:
ATOMS
define and describe?
classify it , draw it and label it
how does it relate to your life?
if it didn't exist how would life be different?
Answers
Describe - Atoms consist of a nucleus made of protons and neutrons orbited by electrons.
How does it relate to your life?
A) Atoms are extremely important structures that make up all of the materials on earth. Atoms are in our bodies and they bond together to form molecules, which make up matter.
If it didn’t exist how would life be different?
A) Atoms make up everything around you, everything you see, hear, touch, smell and taste. With out atoms, the chemical elements couldn’t exist, without chemical elements, then molecules wouldn’t exist, then proteins wouldn’t exist, then life wouldn’t exist, if you removed two atoms, you could still live.
(Can I be marked brainlist? Plz and thanks)
Which of these statements is true?
A.The neutrons have a neutral charge and help stabilize an atom
B.The electrons have a negative charge and are in the nucleus
C.The protons have a negative charge and are in the nucleus
D.The electrons have a positive charge and orbit the nucleus in the electron cloud
Answers
Answer:
Among these statements B is the correct answer.
The process by which cells divide is called
A
O replication
B.
mitosis
C.
respiration
D.
photosynthesis
Answers
the answer is mitosis
What is the name for a particle that has a mass about 1/1835 of a proton, but with a negative charge
Answers
Answer:
Electron
Explanation:
an oxygen tank used for scuba diving has. avolume of 12.0 L .If the pressure of the tank is known to be 204.047 atm and the temperature is 22.0 C(295 K), how many moles of oxygen are contained in the tank
Answers
Answer: 101 moles of oxygen are contained in the tank
Explanation:
According to ideal gas equation:
[tex]PV=nRT[/tex]
P = pressure of gas = 204.047 atm
V = Volume of gas = 12.0 L
n = number of moles = ?
R = gas constant =[tex]0.0821Latm/Kmol[/tex]
T =temperature =[tex]22.0^0C=(22.0+273)K=295K[/tex]
[tex]n=\frac{PV}{RT}[/tex]
[tex]n=\frac{204.047atm\times 12.0L}{0.0821 L atm/K mol\times 295K}=101moles[/tex]
Thus 101 moles of oxygen are contained in the tank