6th grade science plz help Major grade Need help with 4,5, and 6
What is the volume, in L, of 2.50 moles of oxygen gas measured at 25.0oC and a pressure of 104.5 kPa?
Answer:
58.53 L
Explanation:
Ideal gas equation is
PV = nRT
P - the pressure of the gas = 104.5 KPa
V- the volume occupied by the gas
n - the number of moles of gas =2.50
R - the universal gas constant, usually given as 0.0821 atm.L/(mol K)
T - the absolute temperature of the gas.= 298K
[tex]V =\frac{nRT}{P}[/tex]
Now substituting vales we get
[tex]V = \frac{2.5\times0.0821\times298}{104.5\times1000}[/tex]
V = 58.53 L
What is the half life of this element?
A. 80 days B. 40 days C. 5 days D. 10 days
Answer:
c. 5days
Explanation:
there is no question but if it's a graph
the answer is 5days
explain what is meant by an exothermic reaction and write balanced equation for any two exothermic changes
Please do not answer from links
Please answer correctly
Urgent
[tex] \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \red{ \underline{ \large \orange{\tt{ ꧁ A \: N\: S \: W \: E \: R ꧂}}}}[/tex]
✧ [tex] \large{ \red{\tt{E\:X \: O \: T \: H \: E \: R \: M \: I \: C \: \: R \: E \: A \: C \: T\: I \: O \: N}} : }[/tex]
☃ The chemical reaction in which heat is released to the surroundings is called exothermic reaction. The amount of heat energy released is written along with products. This indicates that heat is given out.
[tex] \pink{ \text{Any \: two \: balanced \: equation \: for \: Exothermic \: changes}} : [/tex]
C + O₂ ⇾ CO₂ + HeatCaO + H₂O ⇾ Ca ( OH )₂ + Heatツ Hope I helped! ♡
☂ Have a wonderful day / night ! ☄
[tex] \underbrace{ \overbrace{ \mathfrak{Carry \: On \: Learning}}}[/tex] ✎
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Calculate the pH for a 1.0 x 10-5 M solution of OH at 25°C.
pH = -log[H*), pOH = -log[OH-]
14 = pH + POH
0 pH = 11.00
0 pH = 9.00
0 pH = 6.00
0 pH = 3.00
Answer:
ph=9.00
Explanation:
Given 1.0x10^-15M of OH at 25c
first find Poh from Poh=-log[OH]
then Poh=-log[1.0x10^-5]
from above Ph=5
then find Ph from ph+poh =pw
where pw=14
so
ph+5=14
ph=9.00
The pH for a 1.0 x 10-5 M solution of OH at 25°C is 9.
What is pH?pH is a measure of acidity and basicity of aqueous solution. The range of pH goes from 0 - 14, with 7 being neutral. pH of less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base.pH is the measure of the relative amount of free hydrogen and hydroxyl ions in aqueous or other solutions.In water pH + pOH=14
pH = 14 - pOH = 14 - 5 = 9
From definition, pOH = - log₁₀ [OH⁻]
Thus pOH = -log₁₀ (1 x 10⁻⁵)
= - (-5) = 5
pH + pOH = 14
pH = 14 - pOH
= 14 - 5 = 9
pH = 9
Hence, pH = 9 is the correct answer.
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3. Universal indicator is used to
determine the pH of a solution. Which
statement is correct?
A. Universal indicator turns red in
strong alkali.
B. Universal indicator turns blue in
strong acid.
C. Universal indicator turns orange in
weak acid.
Answer:
C.Universal indicator turns orange in
weak acid.
Explanation:
option A and B are incorrect coz universal indicator turns red in strong acid and in strong alkali (base) it turns blue
PLEASE HELPPP WILL GIVE BRAINLIEST!!!
Answer:
placental mammals
Explanation:
Answer:
B) placental mammals
Explanation:
How is a sound wave transmitted? Please help me I have a test.
Answer: energy is transferred through vibration of air particles or particles of a solid through which the sound travels.
Answer:
Sound is transmitted by vibrating a object and the waves move through particles.
Explanation:
Copper(Ii) Iodate + Potassium Carbonate = Potassium Iodate + copper(I)carbonate into a formula equation ?
Answer:
Cu(IO3)2 + K2CO3 → 2KIO3 + CuCO3
How many moles of NaCl are found in 5.2L of a 0.75 M solution?
Answer 4.45 moles
Explanation:
Can someone please answer this?
Answer:
B) go look on the periodic table for the atomic number
Explanation:
The atomic number is how many protons is in an atom
Answer:
Either A or B
Explanation: Because I learned it on Edge. :)
Predict: Based on your hypothesis, which population(s) would be hurt if bears were added?
Answer:
all of em, unless the bear is normal to the environment
Is heat a from of kinetic or potential energy?
Answer:
its made up of both but I would probably say kinetic
Explanation:
9. Why do bees pollinate flowers?
A. They want to get to food in the flower.
B. They want to make seeds.
C. They want to help the flowers reproduce.
D. They want protection.
Explanation: B.
Bees pollinate in order to sweeten their seed
Answer:
A
Explanation:
Bees make excellent pollinators because most of their lives is spent collecting pollen which acts as a protein to feed their offspring
Which is the conjugate acid of HSO4
Answer:
sulfuric acid
Explanation:
The conjugate acid of HSO4 -1 is H2 SO4. Adding one hydrogen ion to the hydrogen sulfate ion generates the conjugate acid. Its name is sulfuric acid.
Which of the following bonds is classified as a polar bond?
A K-CI
B Br-Br
C Si-F
D S-O
WILL MARK BRAINLIST
Answer:
the answer is b
Explanation:
the answer is b
Compound of KCl has a polar bond as there is a electronegativity difference between potassium and chlorine atoms.
What is a compound?
Compound is defined as a chemical substance made up of identical molecules containing atoms from more than one type of chemical element.
Molecule consisting atoms of only one element is not called compound.It is transformed into new substances during chemical reactions. There are four major types of compounds depending on chemical bonding present in them.They are:
1)Molecular compounds where in atoms are joined by covalent bonds.
2) ionic compounds where atoms are joined by ionic bond.
3)Inter-metallic compounds where atoms are held by metallic bonds
4) co-ordination complexes where atoms are held by co-ordinate bonds.
They have a unique chemical structure held together by chemical bonds Compounds have different properties as those of elements because when a compound is formed the properties of the substance are totally altered.
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what is a characteristic of a strong acid
Answer:
Strong acids have mostly ions in solution, therefore the bonds holding H and A together must be weak. Strong acids easily break apart into ions. Weak acids exist mostly as molecules with only a few ions in solution, therefore the bonds holding H and A together must be strong
Answer:
Bond Strength
Explanation:
Strong acids have mostly ions in solution, therefore the bonds holding H and A together must be weak. Strong acids easily break apart into ions. Weak acids exist mostly as molecules with only a few ions in solution, therefore the bonds holding H and A together must be strong.Aug 15, 2020
i need to write a brief paragraph on why this lab is important, please help!! here is the question!
How can the properties of acids and bases be used to classify solutions?
Answer:
Acids and bases aqueous solutions will conduct electricity because they contain dissolved ions. Therefore acids and bases are electrolytes. strong acids and bases will be electrolytes. weak acids and bases will be weak electrolytes.
why does the atmosphere weigh so much
Answer:
Because the Earth's gravity acts on the atmosphere and holds it down, just as it does all other objects. The weight of the atmosphere is estimated to be about 5.75 quadrillion (5,750,000,000,000,000) tons. Air pressure is the "push" of the atmosphere on the Earth's surface.
Please Help! Brainliest!
Convert the following to milligrams: 5.6 x 10-4 kilograms. Show your work on a separate sheet of paper and attach
with your assignment.
Hi there!
Here's a picture to show you. Does this help?
Which a balanced chemical equation ? O C 7 H 16 +5O 2 6CO 2 +4H 2 O OB C 7 H 16 +11O 2 7CO 2 +8H 2 O C 7 H 16 +14O 2 7CO 2 +5H 2 O OD . C 7 H 16 +22O 2 14CO 2 +16H 2 O
Answer: [tex]C_7H_{16}+11O_2\rightarrow 7CO_2+8H_2O[/tex]
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
The balanced chemical equation is:
[tex]C_7H_{16}+11O_2\rightarrow 7CO_2+8H_2O[/tex]
What type of organism is the common house cat?
F
parasite
G
saprophyte
H
autotroph
J
heterotroph
Answer:
F
parasite
Explanation:
A student weighs an empty flask and stopper and finds the mass to be 53.256 g. She then adds about 5 mL of an unknown liquid and heats the flask in a boiling water bath at 98.8°C. After all the liquid is vaporized, she removes the flask from the bath, stoppers it, and lets it cool. After it is cool, she momen- tarily removes the stopper, then replaces it and weighs the flask and condensed vapor, obtaining a mass of 53.780 g. The volume of the flask is known to be 231.1 mL. The absolute atmospheric pressure in the laboratory that day is 728 mm Hg. a. What was the pressure of the vapor in the flask in atm?
Answer:
a. The pressure in the flask open to the atmosphere during the vaporization of the unknown liquid is equal to the prevailing atmospheric pressure equivalent to 0.957734 atm
Explanation:
The mass of the empty flask and stopper, m = 53.256 g
The volume of the unknown liquid she adds = 5 mL
The temperature of the water in which she heats up the flask = 98.8 °C = 371.95 K
The mass of the flask and the condensed vapor = 53.780 g
The volume of the flask, V = 231.1 mL
The atmospheric pressure, P = 728 mm Hg
a. We note that the student stoppers the flask after all the liquid has evaporated. Therefore, given that the flask was open to the atmospheric pressure as the liquid evaporates, the pressure of the vapor in the flask is equal to the prevailing atmospheric pressure, or 728 mmHg
Using a calculator, 728 mm Hg is equivalent to 0.957734 atm.
Which of the following phases of matter has a fixed volume but not a fixed shape?
A Liquid B Gas C Solid D Plasma
Answer:
C. solidExplanation:
Solid is a hard and not able to flow; not like a liquid or gas. Having no holes; not hollow. Something that is not liquid and gas. Solid has fixed volume but not a fixed shape.
The liquid is something that flows freely; a substance that is not solid or gas.
Gas is a substance that neither liquid nor solid, e.g. air.
Plasma is an electrically neutral ionized gas in an electric discharge; distinctly different from solids and liquids and normal gases.
Therefore, the correct answer is C. solid.
Answer:
A. Liquid
Explanation:
the guy above me is wrong
What is the formula for pH?
Answer:
To calculate the pH of an aqueous solution you need to know the concentration of the hydronium ion in moles per liter (molarity). The pH is then calculated using the expression: pH = - log [H3O+].
Example: Find the pH of a 0.0025 M HCl solution.
The gas phase decomposition of phosphine at 120 °C
PH3(g)1/4 P4(g) + 3/2 H2(g)
is first order in PH3 with a rate constant of 1.80×10-2 s-1.
If the initial concentration of PH3 is 8.48×10-2 M, the concentration of PH3 will be 2.45×10-2 M after
s have passed.
Answer:
The decreasing in concentration occurs after 69.0s
Explanation:
A first order reaction follows the equation:
Ln [A] = -kt + ln[A]₀
Where [A] is the concentration of the reactant after time t
k is rate constant of the reaction
And [A]₀ is the initial concentration of the reactant
Replacing:
Ln 2.45x10⁻²M = -1.80x10⁻²s⁻¹*t + ln8.48x10⁻²
-3.709 = -1.80x10⁻²s⁻¹*t -2.467
-1.2416 = -1.80x10⁻²s⁻¹*t
69.0s = t
The decreasing in concentration occurs after 69.0s
What type of circuit has a broken path that does NOT let current flow through it?
A : Closed circuit
B: Open circut
C : Toggle
D : Switch
Answer:
B
Explanation:
3) What is the mass of 1 mole of selenium (Se)?
Answer:
78.96 grams
Explanation:
I looked it up and that's what I found
hope it helps
Answer:
78.96 g mol
Explanation:
78.96 g mol
in the period table the mass of Se is 78.96 g mol
PLEASE HELP ME ASAP!!!!!!!!!!!!!
2 HNO3(aq) + NO(g) → 3 NO2(g) + H2O(l) ΔG°rxn = ? ΔG°f (kJ/mol) -110.9 87.6 51.3 -237.1
Answer:
[tex]\Delta G_{rxn}=51.0kJ/mol[/tex]
Explanation:
Hello there!
In this case, according to the definition of the Gibbs free energy of reaction in terms of the Gibbs free energy of formation of the involved reactants and products, it is possible for us to compute it as shown below:
[tex]\Delta G_{rxn}=3\Delta _f G_{NO_2}+\Delta _f G_{H_2O}-2\Delta _f G_{HNO_3}-\Delta _f G_{NO}[/tex]
Thus, by plugging in the given data, it is possible to obtain:
[tex]\Delta G_{rxn}=3(51.3)+(-237.1)-2(-110.9)-(87.6)\\\\\Delta G_{rxn}=51.0kJ/mol[/tex]
Best regards!
The standard Gibbs free energy change (ΔG°rxn) for the reaction is 76.7 kJ/mol.
The balanced equation for the reaction is:
2 HNO₃(aq) + NO(g) → 3 NO₂(g) + H₂O(l)
The standard free energy change for a reaction ( ΔG0rxn) can be found out using the equation,
ΔG° = Σ ΔG°fproducts - Σ ΔGf° reactants
ΔG°rxn = ΔH°rxn - TΔS0rxn
∆H°rxn = change in enthalpy of reaction
∆S° = Change in entropy of reaction
T = Temperature ( 298 K )
ΔG°rxn = (3 × ΔG°f(NO₂(g)) + ΔG°f(H₂O(l))) - (2 × ΔG°f(HNO₃)aq)) + ΔG°f(NO(g)))
Substituting the given ΔG°f values:
ΔG°rxn = (3 × 51.3 kJ/mol) + (-237.1 kJ/mol) - (2 × (-110.9 kJ/mol)) + (87.6 kJ/mol)
ΔG°rxn = 153.9 kJ/mol - 237.1 kJ/mol + 221.8 kJ/mol + 87.6 kJ/mol
ΔG°rxn = 226.2 kJ/mol - 149.5 kJ/mol
ΔG°rxn = 76.7 kJ/mol
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