Answer:
n ≈ 2.42 moles
General Formulas and Concepts:
Chem
Ideal Gas Law: PV = nRT
P is pressure in mmHgV is volume in litersn is number of molesR is a constant (62.4 L · mmHg/mol · k)T is temperature in KelvinsK = °C + 273
Explanation:
Step 1: Define
V = 50.2 L
P = 755 mmHg
T = -22.0°C = 251 K
Step 2: Find moles n
(755 mmHg)(50.2 L) = n(62.4 L · mmHg/mol · k)(251 K)
37901 mmHg · L = n(15662.4 L · mmHg/mol)
n = 2.41987 moles
Step 3: Check
We are given 3 sig figs. Follow sig fig rules.
2.41987 moles ≈ 2.42 moles
Unit Test Unit Test Active 13 TIME REMAINING 01:31:26 Chemical A and Chemical B react in an exothermic reaction. What can be known about what will happen when Chemical A and Chemical B are mixed together? O The new substance will need more energy to form its chemical bonds than the old substance will release. More energy will be released from the old substance than the new substance will need to form its chemical bonds. The color will change as a result of the reaction. O The substance will bubble as a result of the reaction. Save and Exit Next Submit Mark this and return
Answer:
More energy is released from the old substance than the new substance needs to form its chemical bonds
Explanation:
Chemical A and Chemical B react in an exothermic reaction. When Chemical A and Chemical B are mixed together more energy will be released from the old substance than the new substance will need to form its chemical bonds. Therefore, option B is correct.
What is an exothermic reaction ?When a chemical reaction goes on, energy is shifted to or from the surroundings. When energy is moved to the surroundings, this is called an exothermic reaction, and the temperature of the surroundings increases.
Examples of exothermic reactions are combustion reactions and many oxidation reactions.
A chemical reaction is exothermic if heat is passed by the system into the surroundings. Because the surroundings are deriving heat from the system, the temperature of the surroundings increases.
Thus, option B is correct.
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Which of the following molecules has a covalent bond?
A) H-F
B) H-Cl
C) H-Br
Which statement best describes evidence that a chemical reaction occurs as a cake bakes
Answer: the cake rises as gas bubbles form in the cake
Explanation: Had a quizziz quiz on this
Answer: The cake rises as gas bubbles form in the baking cake.
Explanation: had a test, got it right.
Which two types of energy are formed by the transformation shown in the
photo?
A. Chemical energy →
thermal energy
n BiThermal energy
electrical energy
C. Thermal energy – chemical energy
D. Chemical energy - electromagnetic energy
SUBMIT
Answer:
A. Chemical Energy --> Thermal Energy
D. Chemical Energy --> Electromagnetic Energy
Explanation:
I took the quiz!
Electric charges that are different attract each other.
True
False
Answer:
it is true bc i looked it up
A student is using colored beads to model 1 molecule of LaTeX: Ca_3\left(PO_4\right)_2C a 3 ( P O 4 ) 2. The student uses blue beads to model Calcium, red beads to model Phosporus, and green beads to model Oxygen. How many of each color will the student need to make their model?
Answer:
3 blue beads
1 red beads
4 green beads
Explanation:
The compound given:
Ca₃PO₄
Elements in the compound are:
Ca
P
O
Number of atoms are :
Ca - 3
P - 1
O - 4
blue beads to model Calcium
red beads to model Phosphorus
green beads to model Oxygen
3 blue beads
1 red beads
4 green beads
A solution containing molecular nonpolar molecules will conduct electricity
True or False?
Answer:
true
Explanation:
In some places, timber companies remove all the trees from entire hillsides when they are
harvesting logs, and farmers till the soil in the fall and leave the ground bare of plants until it is
time to plant in spring. What is the most likely effect of doing either of these things?
A
A. Plants will sprout better.
B. Erosion will happen faster.
C. Soil will stay cooler.
D. Decomposition will speed up.
Answer:
c
Explanation:
soil will stay cooler
Balance the reaction below using the correct coefficient.
__Ag2S --> __Ag + __S8
Answer:
8Ag2S--->16Ag+S8
Explanation:
thats your answer hope it helps
2.) Given that the reaction below is a precipitation reaction, what is the missing symbol?
AND
3.) Which of the following would produce a precipitate when mixed water (H20)?
PLZ HELP IM GONNA FAIL THE SEMESTER!!!! I'LL AWARD BRAINLIEST!!
Answer:
2) (s)
3) PbBr2
Explanation:
2) This is a precipitation rxn which means if forms a solid, We use (s) for solid.
3) Refer to solubility table
Does a reaction occur when aqueous solutions of ammonium carbonate and chromium(III) nitrate are combined? yesno If a reaction does occur, write the net ionic equation. Use the solubility rules provided in the OWL Preparation Page to determine the solubility of compounds. Use the pull-down boxes to specify states such as (aq) or (s). If a box is not needed leave it blank.
Answer:
3 CO₃²⁻(aq) + 2 Cr³⁺(aq) ⇒ Cr₂(CO₃)₃(s)
Explanation:
Let's consider the molecular equation that occurs when aqueous solutions of ammonium carbonate and chromium(III) nitrate are combined.
3 (NH₄)₂CO₃(aq) + 2 Cr(NO₃)₃(aq) ⇒ 6 NH₄NO₃(aq) + Cr₂(CO₃)₃(s)
The complete ionic equation includes all the ions and insoluble species.
6 NH₄⁺(aq) + 3 CO₃²⁻(aq) + 2 Cr³⁺(aq) + 6 NO₃⁻(aq) ⇒ 6 NH₄⁺(aq) + 6 NO₃⁻(aq) + Cr₂(CO₃)₃(s)
The net ionic equation includes only the ions that participate in the reaction and the insoluble species.
3 CO₃²⁻(aq) + 2 Cr³⁺(aq) ⇒ Cr₂(CO₃)₃(s)
Which descriptions are true regarding different muscle types? Select four options.
Cardiac and skeletal muscles are striated.
Skeletal and smooth muscles are nonstriated.
Smooth and cardiac muscles are voluntary.
Heart and digestive muscles are involuntary muscles.
Smooth and skeletal muscles are involved in movement.
Cardiac muscles work to pump blood.
Answer:
1, 4, 5, 6
Explanation:
Answer:
1,4,5,6
Explanation:
Describe the relationship between predator and prey in a balanced ecosystem
Answer:
The predator-prey relationship helps to hold the populations of the two species in equilibrium. ... If the population of prey increases, there is more food for predators. So after a slight period, the predator population is also increasing. If the number of predators increases, more prey is captured.
Explanation:
Answer:
i eat you, you die
Explanation:
thats how life works
Consider the reaction: 3Co2+(aq) + 6NO3¯(aq) + 6Na+(aq) + 2PO43¯(aq) â Co3(PO4)2(s) + 6Na+(aq) + 6NO3¯(aq) Identify the net ionic equation for this reaction.A. 3CO2(aq) + 6NO3(aq) + 6Na+(aq) + 2PO43-(aq) â Co3(PO4)2(s) + 6NaNO3(aq). B. Na+(aq) + NO3-(aq) â NaNO3(aq).C. 3CO2(aq) + NO3(aq) + Na*(aq) + 2PO43-(aq) â Co3(PO4)2(s) + NaNO3(aq).D. 3C02(aq) + 2PO43-(ag) â CO3(PO4)2(s).E. None of these choices are correct.
Answer:
D. 3 Co²⁺(aq) + 2 PO₄³⁻(aq) ⇒ Co₃(PO₄)₂(s)
Explanation:
The complete ionic equation includes all the ions and the insoluble species. Let's consider the following complete ionic equation.
3 Co²⁺(aq) + 6 NO₃⁻(aq) + 6 Na⁺(aq) + 2 PO₄³⁻(aq) ⇒ Co₃(PO₄)₂(s) + 6 Na⁺(aq) + 6 NO₃⁻(aq)
The net ionic equation includes only the ions that participate in the reaction (not spectator ions) and the insoluble species. The corresponding net ionic equation is:
3 Co²⁺(aq) + 2 PO₄³⁻(aq) ⇒ Co₃(PO₄)₂(s)
Identify the necessary parts to build a calorimeter. Select one or more:________ A. Cover. B. An interior paper cup. C. Thermometer. D. An interior styrofoam cup. E. An exterior paper cup An exterior styrofoam cup Conductivity probe.
Answer:
Explanation:
A calorimeter is an instrument used for measuring the heat of reactions and heat capacity. A calorimeter should contain an insulating cover, a thermometer, styrofoam cups (you could have that both on the inside and the outside in the case of a styrofoam calorimeter) and you could also have a conductivity probe (in the form of ignition wires and bulb).
A calorimeter is the analytical device used to measure the heat of the reaction. The construction of calorimeter requires cover, paper cup, thermometer, styrofoam cup, and conductivity probe.
How to build a calorimeter?In a chemical reaction, the amount of heat released or absorbed by the reaction helps in the analysis of various parameters. The calorimeter measures the heat of the reaction.
The construction of a calorimeter requires:
Paper can for the filling of water.Cover to stop the loss of heatStyrofoam cup to allow the reactionThermometer to measure the change in temperatureConductivity probe to allow the transfer of heat energyLearn more about calorimeter, here:
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Which of the following descriptions best describes a weak base?
A. a base that dissociated completely in water
B. a base that generates a lot of hydroxide ions in water
C. a base that has very low concentration in water
D. A base that dissociates only slightly in water
Answer:
umm.. B. a base that generates a lot of hydroxide ions in water.
The descriptions best describes a weak base is a base that dissociates only slightly in water.
What are bases?Bases are those substances which react with acids to neutralize them, generally bases are the compounds of oxides, hydroxides and carbonates of metal elements.
Bases shows dissocation in the aqueous soluition and pH of bases ranges from 7 to 14. Strong bases shows full dissociation into ions and having higher pH values and weak bases shows partial dissociation into ions & having lower pH values.
Hence, option (D) is correct.
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Is SO3 ionic or ionic using the stock system or molecular
Answer:
Molecular
Explanation:
Using the rules for the nomenclature for naming binary covalent (molecular) compounds, the compound SO3 is named sulfur trioxide. The prefix tri- indicates that the oxygen has a subscript of 3 and that a molecule of sulfur trioxide has three oxygen atoms.
Which classes of isomers are easier to separate from each other in the laboratory: enantiomers or diastereomers?
Answer:
diastereomers
Explanation:
Enantiomers are optical isomers that are mirror images of each other. Enantiomers can not be separated by physical methods because the both compounds have almost the same physical properties such as melting points, boiling points, etc. This makes it difficult to separate enanatiomers by conventional methods.
A common method of separating enantiomers is by converting them into diasteromers which are easily separated since diasteromers often have different chemical and physical properties.
Select all possible answers:
Which statement(s) are true about valence electrons?
a. Atoms are very reactive when they have full valence energy levels.
b. Atoms readily lose or gain valence electrons in order to achieve a full
outer energy level.
c. Atoms are stable when they have as many valence electrons as possible.
d. Valence electrons determine many of the properties of an atom.
Answer:
c and d are correct
Explanation:
In A, false because in Valence Electrons, the more the valences, the more stable an atom is.
In B, false because atoms cannot readily gain or lose valence electrons as the number of valence electrons is determined by the column they are in.
In C, true because the more the valence electrons, the more the stability of an atom.
In D, true as electron placing is important and the reactivity of an atom is important.
So C and D are true!
The statement(s) which are true about valence electrons are:
c. Atoms are stable when they have as many valence electrons as possible.
d. Valence electrons determine many of the properties of an atom.
An atom refers to the smallest, indivisible unit that isnmade up of matter and forms all chemical elements.
In Chemistry, an atom comprises three (3) distinct particles and these are;
Protons. Neutrons. Electrons.Valence electrons is simply the number of electrons that is/are present in the outermost shell of the atom of a chemical element.
Generally, valence electrons are typically used to determine whether an atom or group of chemical elements can bond with other chemical elements.
As a general rule, atoms with as many valence electrons as possible are more stable and reaches an octet state.
Lastly, valence electrons are used to determine the chemical properties of of the atom of a chemical element.
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2)
The amount of energy required to remove all the valence electrons from a cesium atom is
A)
944 kJ/mol
B)
376 kJ/mol
C)
520 kJ/mol
D)
238 kJ/mol
Answer:
c 520kj mol
Explanation:
times all the electrons
Which statement describes how phase changes
can be diagrammed as a substance is heated?
A. The phase is on the y-axis and thels
temperature is on the x-axis.
B. The temperature is on the y-axis and the
phase is on the x-axis.
C. The time is on the y-axis and the temperature
is on the x-axis.
D. The temperature is on the y-axis and the time
is on the x-axis.
Answer: d
Explanation:
On edg
If Phosphorus, P, gained 3 electrons, the net ion charge would be
+5
-5
+3
-3
Answer:
-3
Explanation:
Phosphorus becomes phosphide with a -3 charge
Suppose 0.363 g of barium acetate is dissolved in 100. mL of a 25.0 m M aqueous solution of ammonium sulfate. Calculate the final molarity of barium cation in the solution. You can assume the volume of the solution doesn't change when the barium acetate is dissolved in it. Be sure your answer has the correct number of significant digits.
Answer:
Molarity of Ba²⁺ is 0M
Explanation:
Some barium ion, Ba²⁺ is produced when barium acetate is dissolved (Moles of barium acetate = moles of Ba²⁺ in solution). Then, Ba²⁺ reacts with sulfate ion to produce BaSO₄, an insoluble salt. The concentration of Ba²⁺ is the initial concentration - the concentration of SO₄²⁻ in solution.
Initial moles of Ba²⁺:
Moles barium acetate (Molar mass: 255.43g/mol)
0.363g * (1mol / 255.43) = 1.421x10⁻³ moles of Ba²⁺
Moles SO₄²⁻ = Moles of ammonium sulfate:
100mL = 0.100L * (0.025mol / L) = 2.5x10⁻³ moles of SO₄²⁻.
As moles of SO₄²⁻ are higher than moles of Ba²⁺, Molarity of Ba²⁺ is 0M because all moles of Ba²⁺ reacts producing BaSO₄(s), an insoluble salt.
If the mass of a sample of Mg is 0.500 g and is placed in 100.0 g of HCl, the heat gained is 546.5 J. What is the change in temperature assuming the specific heat of HCl is 4.017 J/K*g?
Answer:
1.36 K
Explanation:
We have the following data:
The heat gained by HCl is calculated as:
heat = m x Sh x ΔT
where m is the mass of HCl (100.0 g), Sh is the specific heat of HCl (4.017 J/K.g) and ΔT is the change in temperature. We introduce the data in the mathematical expression to calculate ΔT as follows:
ΔT = heat/(m x Sh) = 546.5 J/(100.0 g x 4.017 J/K.g) = 1.36 K
Therefore, the change in temperature is 1.36 K.
During winter, you can sometimes ice skate outdoors on a frozen lake. Why can’t you ice skate on a lake when it is not frozen?
Answer:
Generally the ice should be more than 4 inches thick to skate on it safely. However, the ice thickness is not always even and there can be thin spots, especially near springs or near river inlets or outlets. Most lakes and ponds don't completely freeze because the ice (and eventually snow) on the surface acts to insulate the water below. Our winters aren't long or cold enough to completely freeze most local water bodies. This process of lakes turning over is critically important to the life in the lake.
Explanation:
In frequency modulation, which wave property remains constant?
Answer:
The correct answer is - Amplitude.
Explanation:
Frequency modulation is a method or procedure that sends or transmits the signals such as radio broadcasting, telecommunication where the value of the transmitted signal is provided by the frequency of a high-frequency wave that carries the signal.
In this method of encoding the information, the amplitude of the carrier remains the same or constant but frequency varies in accordance with the modulating signal.
Answer:
The answer is C Amplitude
Explanation:
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In general, atoms that have a high electronegativity have a ____ first ionization energy and a ____ atomic radius.
NEED ASAP
Select one:
a. low, small
b. high, large
c. low, large
d. high, small
Answer:
The correct option is D
Explanation:
Firstly, let's define the periodicity of these terms and then draw conclusion from there.
Ionization energy is the amount of energy required to remove an electron from a gaseous atom in it's ground state. This property increases across a group in the periodic table.
Electronegativity is the measure of the property/tendency of an atom to attract an electron. This property also increases across a period. Thus, elements that have high electronegativity also have a high ionization energy.
Atomic radius is however the distance between the central nucleus to the outermost electron. This property decreases across the period. Thus, as electronegativity and ionization energy increases, atomic radius decreases.
From the above, it can be deduced that the correct option is d
Answer:high,small
Explanation:
I have the same test and I got it right
When water boils, it pushes upward against the air pressure pushing down on it. If there is less air pressure, how does that affect the pooling point ?
Some organizations are buying sections of forest. Once purchased, these sections will never be cut down. What is most likely the main reason for protecting these sections of forest? A Cause the extinction of undesirable animal species, B Prevent these trees from reproducing too fast, C Maintain the diversity of the living environment. D Crovide more land for agricultural purposes.
Answer:
I think is C
Explanation:
'Cause the questions says "these sections will Never cut down", so that means is proctecting the environment
The first excited electronic energy level of the helium atom is 3.13 x 10-18 J above the ground level. Estimate the temperature at which the electronic motion will begin to make a significant contribution to the heat capacity. That is, at what temperature will the ratio of the population of the first excited state to the ground state be 5.0%?
Answer:
75603.86473 K
Explanation:
Given that:
The 1st excited electronic energy level of He atom = 3.13 × 10⁻¹⁸ J
The objective of this question is to estimate the temperature at which the ratio of the population will be 5.0 between the first excited state to the ground state.
The formula for estimating the ratio of population in 1st excited state to the ground state can be computed as:
[tex]\dfrac{N_2}{N_1} = e ^{^{-\dfrac{(E_2-E_1)}{KT}}} = e ^{^{-\dfrac{(\Delta E)}{KT}}}[/tex]
From the above equation:
Δ E = energy difference = 3.13 × 10⁻¹⁸ J
k = Boltzmann constant = 1.38 × 10⁻²³ J/K
[tex]\dfrac{N_2}{N_1} = 0.5[/tex]
Thus:
[tex]0.05 =e^{^{ -\dfrac{3.13 \times 10^{-18} \ J}{1.38\times 10^{-23 \ J/K}\times T}}}[/tex]
[tex]In (0.05) = { -\dfrac{3.13 \times 10^{-18} \ J}{1.38\times 10^{-23 \ J/K}\times T}}}[/tex]
[tex]-3.00 = { -\dfrac{3.13 \times 10^{-18} \ J}{1.38\times 10^{-23 \ J/K}\times T}}}[/tex]
[tex]-3.00 = -226811.5942 \times \dfrac{1}{T}[/tex]
[tex]T = \dfrac{-226811.5942}{-3.00 }[/tex]
T = 75603.86473 K