Answer:
The correct answer is B. Hypothesis
Explanation:
Which of the following statements is true about exothermic reactions?
Answer:
An Exothermic Reaction , gives off more heat, and a little energy to its surroundings.
this can helps us figure out that the answer is , C, More heat is given off into its products.
Explanation:
A piece of dry ice at -76°C begins to sublimate (solid to
gas) when placed at the counter at room temperature. How
many bars are in the final phase energy (Eph)?
Answer:
D
Explanation:
4 bars
1) How many moles are in 4.0x10^24 atoms?
Answer:
6.64 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{4 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 6.644518...[/tex]
We have the final answer as
6.64 molesHope this helps you
The molar solubility of CaSO4 in water is 0 .67 gram per liter of solution. Calculate the Ksp.
Answer:
Ksp = 2.4 * 10⁻⁵
Explanation:
The equation for the dissolution and dissociation of CaSO4 in water is given as: CaSO₄ ---> Ca²⁺ + SO₄²⁻
The expression for the Ksp of the dissociation equation above is:
Ksp = [Ca²⁺] [SO₄²⁻]
The molar ratio of the dissociated ions and the solute is 1 : 1, this means that every 1 mole of CaSO₄ that dissolves produces 1 mole of Ca²⁺ and SO₄²⁻ each
The molar solubility of a substance is the number of moles that dissolve per liter of solution.
molar solubility of CaSO₄ = number of moles /liter of solution
number of moles of CaSO₄ = mass/molar mass
molar mass of CaSO₄ = 136 g/mol
number of moles of CaSO₄ = 0.67/136 = 0.0049 moles
molar solubility of CaSO₄ = 0.0049 mol/ 1 L = 4.9 * 10⁻³ moles per liter
therefore, molar solubility of CaSO₄ = 4.9 * 10⁻³
Ksp = (4.9 * 10⁻³) (4.9 * 10⁻³)
Ksp = 2.4 * 10⁻⁵
Answer:
2.4 * 10^-5
Explanation:
Molar solubility of CaSO4 = 0 .67 g/L/136 g/mol = 4.9 * 10^-3 Mol/L
Given that;
CaSO4(s) -------> Ca^2+(aq) + SO4^2-(aq)
Hence, Ksp = [Ca^2+] [SO4^2-]
Where [Ca^2+] =[SO4^2-]=s
Ksp = s^2
since s = 4.9 * 10^-3 Mol/L
Ksp = (4.9 * 10^-3 Mol/L)^2
Ksp = 2.4 * 10^-5
At which point is crust neither created nor destroyed?
island chain
mid-ocean ridge
divergent boundary
transform boundary
Answer:
transform battery
Explanation:
Answer: D. Transform Boundary
Explanation: I did the test.
Which defines the average inetic energy of a system's particles?
O density
O pressure
O temperature
O volume
Write
the following separation techniques?
a. Filtration
b. Evaporation
C. Fractional distillation
d. Chromatography
Answer:
Explanation: Fractional distillation
what's the formula for na and f , ca and br , mg and O
Answer:
NaF, CaBr2, MgO
Explanation:
Hi! For this problem, you are going to want to look at the charges of the elements in order to write their formulas.
NaF: Na has a charge of +1 and F has a charge of -1. This means that they have a 1:1 ratio and the formula is written as such - NaF.
CaBr2: Ca has a charge of +2 and Br has a charge of -1. For this problem you want to make sure that their formal charge (the charge of the entire molecule) equals 0. This means that the negative charges need to equal the positive charges. Looking at this, you are going to need to Br ions with a charge of -1 to equal one Ca ion with a charge of +2 - CaBr2.
MgO: Mg has a charge of +2 and O has a charge of -2. This means that they have a 2:2 ratio which simplifies to a 1:1 ratio and the formula is written as such - MgO.
Hope this helps!
Please answer it truthfully please
Answer:
False
Explanation:
Chemical and Physical changes happen uniquely, they cannot happen at the same time. When you crumble a piece of paper you don't change its chemical form you change its physical form. When a piece of metal rusts its chemical composition changes, leading me to believe it is false.
Good luck on the rest of your assignment/test!
Relate the properties of atoms, their position in the periodic table, and their number of valence electrons to their chemical reactivity.
Answer:
Explanation:
An atom is the smallest unit of an element that can take part in a chemical reaction. Atoms are made up of protons, neutrons and electrons. Atoms can exist as a monoatomic (such as in the case of Helium, Xenon and Neon) or as diatomic (such as in the case of oxygen and nitrogen). Atoms take part in a chemical reaction and there reactivity varies among themselves.
From the above, it can be deduced that atoms have protons, neutrons and electrons. The number of protons (which is positively charged) of an atom determines it's position on the periodic table because elements in the periodic table are arranged according to the number of protons (called atomic number). The electron(s) present in the outermost shell of each atom (called valence electrons) determines there chemical reactivity. What happens here is that, all atoms (except noble gases) want to achieve there duplet or octet configuration so as to become stable. This octet configuration means they want to have there outermost shell completely filled (with eight electrons or two electrons for duplet). They usually achieve this configuration by taking part in chemical reactions. Thus, when an atom has just one electron in it's outermost shell, it becomes easy to lose it to another atom by way of interacting with it in a chemical reaction. When it loses this single electron (valence electron) in it's outermost shell, it becomes stable with the inner completely filled shell (that would be the new outermost shell). Examples include Lithium, sodium and potassium. Sodium (with eleven electrons and three shells) would lose the single electron in it's outermost shell so as to have just two shells with the second shell completely filled with eight electrons. Thus, the more the valence electron to be lost to achieve the octet structure, the lesser the reactivity of the atom.
Also, an atom that has just one electron to complete it's own outermost shell and thus achieve it's octet structure is also highly reactive. This is also because it is easy for this atom to receive a single electron and become completely filled. Examples include chlorine, fluorine and iodine. Fluorine (with nine electrons and two shells) will easily accept one more electron so as to achieve it's octet structure with a completely filled outermost shell (of eight electrons). Thus, the lesser the electrons to be gained to achieve the octet configuration, the higher the chemical reactivity of such atoms. Noble gases have extremely low or no reactivity at all for this reason because it has a completely filled outermost shell (no losing or donating).
It should also be noted that metals (which are found on the left of the periodic table) exist as monoatomic while gases (which are found on the right), with the exception of noble gases, are mostly diatomic.
The reactivity of atoms of elements in the periodic table depends on their valency as well as their position in the periodic table.
The periodic table contains an arrangement of atoms in order of increasing atomic numbers. Elements in the periodic table are arranged in groups. Each group of elements have atoms that contain the same number of valence electrons.
Atoms of alkali and alkaline earth metals as well as atoms of halogens are highly reactive. This has something to do with the number of valence electrons they contain. The alkali and alkaline metals give out their electrons easily are high reactive while the halogens accept electrons easily are also highly reactive.
Alkali and alkaline earth metals have a few valence electrons so they give them out easily. Halogens have seven valence electrons hence they accept electrons easily. Reactivity of metals generally decreases from left to right in the periodic table while the reactivity of nonmetals increases from left to right. The elements of group 18 are placed in the last group because they are unreactive.
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in which type of bond are electron shared between atoms?
A. ionic
B.covalent
C.metallic
Would a highly conductive, malleable, and lustrous solid be a metal, nonmetal, or metalloid?
Which three are advantages of asexual reproduction?
A:Offspring are more likely to survive environmental changes.
B:Some offspring are more likely to survive a disease.
C:Less energy is required to reproduce.
D:The population can increase from only one parent.
E:The population can increase quickly.
Answer:
sorry if I get this wrong I think it is C
Explanation:
Which elements are considered metals? Non-metals? Metalloids?
The answer is in the photo.
which of the following could be classified as producing a physical change?
through which filter did water went through faster?
Answer:
The filter that water went through faster is Filter paper
A sample of helium gas at 841 mmHg and 14.7°C is heated to 84.7°C at constant volume. Calculate its final pressure (in atm).
_________________ atm. Do NOT enter unit. Report your final answer with 3 SFs.
Answer: 1.38
Explanation:
Gay-Lussac's Law: This law states that pressure is directly proportional to the temperature of the gas at constant volume and number of moles.
[tex]P\propto T[/tex] (At constant volume and number of moles)
[tex]\frac{P_1}{T_1}=\frac{P_2}{T_2}[/tex]
where,
[tex]P_1[/tex] = initial pressure of gas = 841 mm Hg
[tex]P_2[/tex] = final pressure of gas = ?
[tex]T_1[/tex] = initial temperature of gas =[tex]14.7^0C=(14.7+273)K=287.7K[/tex]
[tex]T_2[/tex] = final temperature of gas = [tex]84.7^0C=(84.7+273)K=357.7K[/tex]
[tex]\frac{841}{287.7}=\frac{P_2}{357.7}[/tex]
[tex]P_2=1045.6mm Hg=1.38atm[/tex] ( 760 mm Hg = 1atm )
Thus the final pressure is 1.38
4. Kendrick drags his bat out to play baseball. which statement best describes the science of what he did?
O Kendrick would use less energy if he dragged the bat faster.
Kendrick did not have to work to move the bat because he dragged it.
Kindrick gave the bat potential energy.
Kindrick gave the bat kinetic energy.
Explanation:
Kendrick gave the bat potential Energy
How many
electrons does Oravetium contain
Which chemical equation below is not balanced?
- 3 MgSO4 + 2 Nag PO4 → Mgs (PO4),+3 Na, S04
- 2 NaOH + HNO, → NaNO, + 2 H,0
- CH12 O6 4 6O2 → 6 CO, + 6 H,0
- HBr AGNO, → HNO, + AgBr
pic if needed ;)
Answer:
B
Explanation:
The second one is not balanced correctly.
2 NaOH + 2HNO3 → 2NaNO3 + 2 H20
I didn't notice this before but it can be balanced without the twos.
NaOH + HNO3 → NaNO3 + H20
It was still wrong. It needed to have the twos removed, not 2 more added. Adding two more isn't wrong, but it should be balanced without 2s if at all possible.
Calculate the energies of the n=2 and n=3 states of the hydrogen atom in Joules per
atom
Answer:
See Explanation
Explanation:
Positional Energy for electron as function of principle energy level (n)
=> Eₙ = -A/n²; A = 2.18x10⁻¹⁸J
Positional Energy for electron in n=2 => E₂ = -2.18x10⁻¹⁸/(2)² = -5.45x10⁻¹⁹J
Positional Energy for electron in n=3 => E₃ = -2.18x10⁻¹⁸/(3)² = -2.42x10⁻¹⁹J
ΔE(n=3→2) = -5.45x10⁻¹⁹J - (-2.42x10⁻¹⁹J) = -3.03x10⁻¹⁹J
which is a way to express concentration of a solution? parts per billion moles molar mass force per square meter
Answer:
parts per billion
Explanation:
I took the quiz
Answer:
parts per billion
Explanation:
edge 2021
An ideal gas sample is confined to 3.0 L and kept at 27 °C. If the temperature is raised to 77 °C and the initial pressure was 1500 mmHg, what is the final pressure?
The gas is confined in 3.0 L container ( rigid container) ⇒ the volume remains constant when the temperature is increased from from 27oC to 77oC and therefore V1=V2 .
Hope it helps you please mark as brainlistIdeal gas law is valid only for ideal gas not for vanderwaal gas. Ideal gas is a hypothetical gas. Vanderwaal gas can behave as ideal gas at low pressure and high temperature. Therefore the final pressure is 1,750 mmHg.
What is ideal gas equation?Ideal gas equation is the mathematical expression that relates pressure volume and temperature.
Mathematically the relation between Pressure, volume and temperature can be given as
PV=nRT
where,
P = pressure of gas
V= volume of gas
n =number of moles of gas
T =temperature of gas
R = Gas constant = 0.0821 L.atm/K.mol
At constant volume, the above equation can be rearranged as
P₁/T₁ = P₂/T₂
Substituting all the given values in the above equation, we get
1500 ÷300= P₂÷350
P₂ =1,750 mmHg
Therefore the final pressure is 1,750 mmHg.
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find the number of hydrogen atoms of an alkyl group with 2 carbon atoms if n=2
Answer:
5
Explanation:
An alkyl group is a functional group that contains only hydrogen and carbon atoms. It has the general formula: CnH2n+1.
Since n=2, plug it into the formula.
C2H2(2)+1
=
C₂H₅
Hope that helps.
In the organization of living things, tissues combine to form
A)Cells
B)communities
C) organisms
D)Organs
Answer:
D
Explanation:
Answer:d
Explanation:
Becky places a strip of metal into a clear liquid and they react. A has given off . The liquid is most likely which kind of substance?
Answer:
The liquid is likely to be a base e.g Sodium hydroxide solution or Ammonia solution
The liquid is likely to be a Base .
Acid and baseThe terms acid and base describe chemical characteristics of many substances that we use daily. Acidic things taste sour. Basic or alkaline things taste soapy. Strong acids are corrosive and strong bases are caustic; both can cause severe skin damage that feels like a burn. However, mild acids and bases are common and relatively harmless to us.
2 H2O ⇌ 1 H3O+ + 1 OH-
Examples of bases are sodium hydroxide, calcium carbonate and potassium oxide. A base is a substance that can neutralize the acid by reacting with hydrogen ions. Most bases are minerals that react with acids to form water and salts.Basic substances react to aqueous solutions by accepting protons, giving away electrons, or releasing hydroxide ions. They neutralize acids by reacting with hydrogen ions to form salts and water. A base that dissolves in water is also known as an alkali.The scale has values ranging from zero (the most acidic) to 14 (the most basic). As you can see from the pH scale above, pure water has a pH value of 7. This value is considered neutral—neither acidic or basic.Learn more about base, refer
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Can someone help me I only have 5 minutes left.
Consider the equation:
4Al + 3O2 = 2Al2O3
Is this equation balanced? Why or why not?
The equation is balanced. There are 4 aluminium atoms and 6 oxygen atoms on each side.
Which process is constructive?
A:Water wears away rocks in a river.
B:Wind removes sand from a beach.
C:volcano forms an island in the ocean.
D:An earthquake breaks apart a cliff on a mountain.
Find the volume of
this object.
5 cm
5 cm
5 cm
A
15 cm3
B
125 cm3
C
30 cm3
Answer: B. [tex]125\ cm^3[/tex].
The volume of the given object = [tex]125\ cm^3[/tex]
Explanation:
Given : Dimensions of an object : 5 cm x 5 cm x 5 cm [ it is a cube with all equal sides]
Formula to find the volume of a cube = [tex](side)^3[/tex]
[tex]=5^3\ cm^3=125\ cm^3[/tex]
Hence, the volume of the given object = [tex]125\ cm^3[/tex]
Therefore , the correct option is B. [tex]125\ cm^3[/tex].