Answer:
I literally got this from google.
Explanation:
In ordinary air, sodium metal reacts to form a sodium hydroxide film, which can rapidly absorb carbon dioxide from the air, forming sodium bicarbonate. ... In a comparatively dry atmosphere, sodium burns quietly, giving off a dense white caustic smoke, which can cause choking and coughing.
Happy almost Halloween! :)
Convert 15.5 pounds to kilograms. Please and thank you so much!!
Answer:
7.030682 kg
hope it helps!
Answer:
7.030682
Explanation:
help pls
Which process of sedimentary rock formation occurs last?
cementation
compaction
deposition
erosion
Answer:
Compaction.
Explanation:
All the others are before this.
Consider the reaction pathway graph below.
Which statement best describes this graph?
This is an exothermic reaction with a positive ΔHrxn.
This is an exothermic reaction with a negative ΔHrxn.
This is an endothermic reaction with a positive ΔHrxn.
This is an endothermic reaction with a negative ΔHrxn.
Answer:
This is an endothermic reaction with a positive ΔHrxn.
Explanation:
From the question given above, we can see clearly that the energy of the product (Hp) is greater than the energy of the reactant (Hr). This simply means that the reaction is endothermic as the enthalpy change (ΔH) for the reaction will be positive.
Enthalpy change (ΔH) = Heat of product (Hp) – Heat of reactant (Hr)
ΔH = Hp – Hr = positive
NOTE: A reaction with positive enthalphy change (ΔH) is termed endothermic reaction.
Answer:
C
Explanation:
edg 2020
An aqueous solution of Pb(NO3)2 is made by placing 275 g of solid Pb(NO3)2 into a volumetric flask and adding water to the 1.00 L mark (assume that 775g of water has been added to achieve this total solution volume). (Assume MW of Pb(NO3)2 = 331g/mole) A) What is the molarity (M) of this solution? B) What is the molality (m) of this solution? C) What is the mass % of Pb(NO3)2 in this solution? D) What is the mole fraction of Pb(NO3)2 present in this solution?
Answer:
A) 0.831 M
B) 1.07 m
C) 26.2%
D) 0.0189
Explanation:
A) First we convert the mass of Pb(NO₃)₂ to moles:
275 g ÷ 331 g/mol = 0.831 mol Pb(NO₃)₂Then we divide it by the total volume (1.00 L) to calculate the molarity:
0.831 mol / 1.00 L = 0.831 MB) We convert the grams of water to kilograms:
775 g / 1000 = 0.775 kgThen we divide the Pb(NO₃)₂ by the kilograms of water:
0.831 mol / 0.775 kg = 1.07 mC) We divide the mass of Pb(NO₃)₂ by the total mass of the solution:
[tex]\frac{gPb(NO_{3})_{2}}{gPb(NO_{3})_{2}+gH_{2}O}[/tex] *100% [tex]=\frac{275}{275+775}[/tex] * 100% = 26.2%D) We calculate the moles of water:
775 g H₂O ÷ 18g/mol = 43.1 mol H₂OThen we divide the Pb(NO₃)₂ moles by the total number of moles:
[tex]\frac{0.831}{0.831+43.1}[/tex] = 0.0189Which pair of elements will form a covalent bond?
How does an anion form?
A. An anion forms when a stable atom loses one or more neutrons.
B. An anion forms when a stable atom loses one or more protons.
C. An anion forms when a stable atom gains one or more electrons.
D. An anion forms when a stable atom loses one or more electrons.
The osmotic pressure exerted by a solution is equal to the molarity multiplied by the absolute temperature and the gas constant . Suppose the osmotic pressure of a certain solution is measured to be at an absolute temperature of . Write an equation that will let you calculate the molarity of this solution. Your equation should contain only symbols. Be sure you define each symbol other than . Your equation: Definitions of your symbols:
Answer:
c = π / R × T
Explanation:
The osmotic pressure exerted by a solution is equal to the molarity multiplied by the absolute temperature and the gas constant R . Suppose the osmotic pressure of a certain solution is measured to be 22 atm at an absolute temperature of 353 K. Write an equation that will let you calculate the molarity c of this solution. Your equation should contain only symbols. Be sure you define each symbol other than R.
Step 1: Given data and definition of the symbols
Osmotic pressure (π): 2.2 atmMolarity of the solution (c): ?Ideal gas constant (R): 0.08206 atm.L/mol.KAbsolute temperature (T): 353 KStep 2: Write an equation that will let you calculate the molarity of this solution, in terms of symbols
The osmotic pressure is a colligative property that can be calculated using the following expression.
π = c × R × T
We can rearrange this expression to calculate the molarity of the solution.
c = π / R × T
Question 1 of 10
What is technology?
A. An understanding of something new.
B. The steps that engineers go through to create a product.
C. Something created using science for use by society.
D. A method that is used to solve problems,
SUBMIT
Answer:
C.
Explanation:
You can use the series of elimination for this. First, you look at A. Technology is not an understanding of something new, so we cross that out. Second, you look at B. Technology isn't a series of steps, so we can mark that one off. Third, you look at C. Technology is something created using science for use by society, so we can keep that in mind. Lastly, we check D. Technology doesn't match up to the definition, so we can cross that one out. The answer that would make the most sense would be D.
A sample of sodium bicarbonate is placed in an evacuated container at allowed to reach equilibrium. What will be the total pressure?
Complete Question
Sodium carbonate, Na2CO3(s), can be prepared by heating sodium bicarbonate, NaHCO3(s).
2NaHCO3(s) ------> Na2CO3(s) + CO2(g) + H2O(g) Kp = 0.23 at 100oC
If a sample of NaHCO3 is placed in an evacuated flask and allowed to achieve equilibrium at 100oC, what will the total gas pressure be?
Answer:
The value is [tex]P_T = 0.959 \ atm [/tex]
Explanation:
From the question we are told that
The equation is
[tex]2NaHCO_3_{(s)} \rightarrow Na_2CO_3_{(s)} + CO2_{(g)} + H2O_{(g)}[/tex]
Generally the equilibrium partial pressure is mathematically represented as
[tex]K_p = P_{CO_2} + P_{H_2O}[/tex]
Here
[tex] P_{CO_2} \ and \ P_{H_2O}[/tex] are partial pressures of [tex] CO_2 \ and \ H_2O [/tex] gases
Note: when writing the formula for equilibrium partial pressure we consider only the gas in the reaction
Let assume that
[tex]P_{CO_2} = a[/tex]
Generally [tex]P_{CO_2} = P_{H_2O}[/tex] since they are both products of the reaction
So
[tex]K_p = a^2 [/tex]
From the question we are told that [tex]K_p = 0.23 [/tex]
So
[tex] 0.23= a^2 [/tex]
=> [tex] a = \sqrt{0.23} [/tex]
=> [tex] a = \sqrt{0.23} [/tex]
=> [tex] a = 0.4796 \ atm [/tex]
So
[tex]P_{CO_2} = 0.4796 \ atm[/tex]
and
[tex]P_{H_2O} = 0.4796 \ atm [/tex]
So the total pressure is
[tex]P_T = 0.4796 + 0.4796[/tex]
=> [tex]P_T = 0.959 \ atm [/tex]
A block of lead weighs 11.3 grams. How many atoms of lead are in this sample?
• Use 6.022 x 1023 mol
for Avogadro's number.
Answer:
To get the number of atoms in this sample, we first need the number of moles of lead in 11.3 grams
Number of moles of Lead:
Molar mass of lead = 207 grams / mol
Number of moles = given mass / molar mass
Number of moles = 11.3 / 207
Number of moles = 0.05 moles
Number of atoms of lead in 11.3 gram sample:
Number of atoms = Number of moles * avogadro's number
Number of atoms = 0.05 * 6.022 * 10²³
Number of atoms = 5 * 10⁻² * 10²³ * 6.022
Number of atoms = 30.11 * 10²¹
11.3 g block of lead contains 3.29×10²² atoms
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.022×10²³ atoms. Thus,
1 mole of lead = 6.022×10²³ atoms
Recall:
1 mole of lead = 207 g
Thus,
207 g of lead = 6.022×10²³ atomsWith the above information in mind, we can obtain the number of atoms in 11.3 g block of lead as illustrated below:
207 g of lead = 6.022×10²³ atoms
Therefore,
11.3 g of lead = (11.3 × 6.022×10²³) / 207
11.3 g of lead = 3.29×10²² atomsThus, 11.3 g block of lead contains 3.29×10²² atoms
Learn more: https://brainly.com/question/9758372
Which of the following elements has the largest atomic radius? Bromine, Barium, Magnsium, Zinc
Answer:
Atomic radii vary in a predictable way 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 across a period. Thus, helium is the smallest element, and francium is the largest.
Explanation:
A 25.00-mL aliquot of a nitric acid solution of unknown concentration is pipetted into a 125-mL Erlenmeyer flask and 2 drops of phenolphthalein are added. The above sodium hydroxide solution (the titrant) is used to titrate the nitric acid solution (the analyte). If 12.75 mL of the titrant is dispensed from a burette in causing a color change of the phenolphthalein, what is the molar concentration of the nitric acid solution? (Show all steps for calculating the answer.)
Answer: 0.0611 M HNO3
Answer:
0.0611M of HNO3
Explanation:
The concentration of the NaOH solution must be 0.1198M
The reaction of NaOH with HNO3 is:
NaOH + HNO3 → NaNO3 + H2O
1 mole of NaOH reacts per mole of HNO3.
That means the moles of NaOH used in the titration are equal to moles of HNO3.
Moles HNO3:
12.75mL = 0.01275L * (0.1198mol / L) = 0.0015274 moles NaOH = Moles HNO3.
In 25.00mL = 0.025L -The volume of the aliquot-:
0.00153 moles HNO3 / 0.025L =
0.0611M of HNO3Pls, Help ASAP with 30 points!!!
Describe the similarities and differences between the eruptions of
less gassy and more gassy magma.
Answer:
the difference is tyat eruptions of less gassy and more gassy is that the less gassy doesnt retain as much gas as the more gassy one and thus the eruption of the less gassy is less damage to the more gassy
Wht is 30.00 grams of H3PO4
Answer:
0.31 mol
Explanation:
Question 14 (1 point)
Calculate the molarity of a solution made by dissolving 15.25 g lithium chloride (Lici)
in 250 mL of solution
61 M LICI
2
1.4 M LICI
5
0.36 M LICI
18
0.061 M Lici
0.0014 M LICI
Answer:
Molarity = 1.4 M
Explanation:
Given data:
Mass of LiCl = 15.25 g
Volume of solution = 250 mL (250/1000 = 0.25 L)
Molarity of solution = ?
Solution:
Molarity is used to describe the concentration of solution. It tells how many moles are dissolve in per litter of solution.
Formula:
Molarity = number of moles of solute / L of solution
Now we will calculate the number of moles of LiCl.
Number of moles = mass/molar mass
Number of moles = 15.25 g/ 42.39 g/mol
Number of moles = 0.36 mol
Molarity:
Molarity = 0.36 mol / 0.25 L
Molarity = 1.4 M (M= mol/L)
A plant uses carbon dioxide and water to form food and oxygen. Why is this a chemical change?
Answer:
The plant uses carbon dioxide and water to make an entirely new chemical hence chemical change.
Explanation:
Plants create their own 'food', they turn carbon dioxide water and sunlight to create starch and glucose..
Answer:
The properties of carbon dioxide and oxygen are different.
Explanation:
im taking the exam right now and Im pretty sure it's D The properties of carbon dioxide and oxygen are different.
I NEED HELP ASAP
1.Compare and contrast starch, cellulose, and glycogen. Include the monomers, function, and what type of organism they are found?
2. Describe the relationship between DNA and the structure of proteins. How might a change in the order of nucleotides result in a non-functional protein?
ANYTHING WILL HELP...WILL GIVE A BRAINLY
Answer:
the second on is, Changing the sequence of nucleotides in the DNA molecule can change the amino acids in the final protein, leading to protein malfunction. If insulin does not function correctly, it might be unable to bind to another protein (insulin receptor).
the first one is, These three polysaccharides differ in their glycosidic linkages and their functions too. Starting from the cellulose which is the monomer of beta glucose and is found in plant cell wall only. While Starch and Glycogen act as the carbohydrate reserve in plants and animals respectively. Though their chains have slight differences at the branching point, which is described below.
Explanation:
hope it helps
Which question must be answered to complete the table below?
A 3-column table with 3 rows. Column 1 is labeled alpha decay with entries alpha particles, plus 2 and low. Column 2 is labeled Beta Decay with entries no entry, electron negative 1 positron positive 1, and medium. Column 3 is labeled Gamma decay with entries gamma rays, 0 and high.
a. What kind of shielding will block beta decay?
b. What is the penetrating power of beta decay?
c. What kind of particles are produced by beta decay?
d. How massive are the particles in beta decay?
Answer:
c
Explanation:
A 500. mL gas sample is collected over water at a pressure of 740 mmHg and 25.0 °C. What is the volume of the dry gas at STP?
Answer:
Volume of dry gas at STP = 0.432 liters or 432 ml
Explanation:
Given:
Pressure (P) = 740 mmHg - 24 mmHg = 716 mmHg
Temperature (t) = 25 degrees C + 273 K = 298 K
500 ml = 0.5 l
Find:
Volume of dry gas at STP
Computation:
[P1][V1] / T1 = [P2][V2] / T2
[716][0.5] / 298 K = [760][ x Liters] / 273 K
x = 0.432 Liters
Volume of dry gas at STP = 0.432 liters or 432 ml
describe the structure and function of gamma rays
Answer:
A gamma ray is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves and gives off the highest photon energy. The energy spectrum of gamma rays can be used to identify the decaying radionuclides using gamma spectroscopy.
Explanation:
PRACTICE PROBLEM Two compounds, A and B, have the same molecular formula, C6H8. Both A and B react with two molar equivalents of hydrogen in the presence of platinum to yield cyclohexane. Compound A shows three signals in its broadband decoupled NMR spectrum. Compound B shows only two NMR signals. Compound A shows an absorption maximum at 256 nm, whereas B shows no absorption maximum at wavelengths longer than 200 nm. What are the structures of A and B
Answer:
See explanation
Explanation:
One basic thing that we must keep in mind is that A and B are both dienes.
The NMR spectrum and absorption maxima of A and B indicates that A may be a conjugated diene while B may be an isolated diene.
Remember that conjugated dienes shift the absorption maxima to longer wavelengths due to π - π* transition.
The two structures attached may suffice for compounds A and B
Two elements in the same period have the same number of _____ _____ in their electron clouds.
Answer:
outer electrons
Explanation:
Answer:
Energy levels
Explanation:
27.8 mL solution of 0.797 M HCHO2 with 0.928 M NaOH. What is the pH for the solution at the equivalence point in the titration?
Answer:
8.69 is the pH at the equivalence point
Explanation:
Formic acid, HCHO₂, reacts with NaOH as follows:
HCHO₂ + NaOH → NaCHO₂ + H₂O.
At the equivalence point you will have in the reaction just NaCHO₂ and H₂O. The concentration of NaCHO₂ will be:
Moles: 0.0278L * 0.797mol/L = 0.02216moles
To reach the equivalence point it is necessary to add:
0.02216mol * (1L / 0.928mol) = 0.0239L
Total volume in the equivalence point:
0.0278L + 0.0239L = 0.0517L
Concentration: 0.02216moles / 0.0517L = 0.429M
The equilibrium of NaCHO₂, CHO₂⁻, in water is:
CHO₂⁻(aq) + H₂O(l) ⇄ OH⁻(aq) + HCHO₂(aq)
Where Kb, 5.56x10⁻¹¹ is defined as:
5.56x10⁻¹¹ = [OH⁻] [HCHO₂] / [CHO₂⁻]
In the equilibrium, it is produced X OH⁻ and HCHO₂, and as concentration of NaCHO₂ is 0.429M:
5.56x10⁻¹¹ = [X] [X] / [0.429M]
2.383x10⁻¹¹ = X²
4.88x10⁻⁶ = X = [OH⁻]
As pOH = -log [OH⁻]
pOH = 5.31
And pH = 14 - pH
pH = 8.69 is the pH at the equivalence point
27. A compound has a mass of 2.6632 10 2 g/mol. The number of significant figures in this mass
is —
A. 2
B. 4
C. 5
D. 7
Answer:
its b
B. 4
Explanation:
Is nuclear fission exothermic or endothermic? Explain your answer.
Answer:
Exothermic
Explanation:
Nuclear fission means splitting, so there is a lot of energy being released.
If a central atom of a molecule only has two electron domains, what is the bond angle associated with the molecule?
120o
180o
90o
109.5o
Answer:
I think it's C.90º
Explanation:
Answer:
180o
Explanation:
It is 180 degrees because the central atom is the atom in the middle of two electrons. Think about it like a straight line, a straight line is equal to 180 degrees. One electron connected to the central atom will be 90 degrees and if there's another electron, it will be 180 degrees.
Hope this helps:)
which of the following determines an object’s ability to float in water?
a. how much the object weighs
b. what the mass of the object is
c. how dense the object is
d. the volume of the object
Rahul and Manav each were given a mixture of iron filings and sulphur powder. Rahul heated the mixture strongly and a new substance was formed. Write three points of difference between the two.Required to answer.
Answer:
sure
Explanation:
The substance formed after heating the mixture of that of Rahul is caleed a compound. Whereas, Manav's mixture still remains in its current stae that is a heterogeneous mixture.
The compound formed is in black in color whereas the mixture is a mix of brownish-red and yellow.
The compound is a homogeneous mixture whereas the mixture is a heterogenous mixture because of its uneven distribution.
For something to be considered
dead, it used to do what?
Answer:
breathe,eat, and drink i guess
An increase in temperature results in A) a decrease in the required activation energy while the reaction rate remains constant. B) an increase in reaction rate due to a decrease in the kinetic energy of the reactants. C) an increase in the rate of reaction because reactant molecules collide with greater energy. D) an increase in both the reaction rate and activation energy due to increased kinetic energy.
Answer:
C) an increase in rate of reaction because reactant molecules collide with greater energy
Explanation:
Temperature is one of the factors that affect the rate of a reaction. The rate of a reaction increases with an increase in temperature and vice versa. When the temperature of a reaction increases, the kinetic energy of the reactant molecules increases causing them to react at a faster rate.
The reactant molecules respond to an increase in temperature by colliding at a faster rate due to an increased kinetic energy between the reactant molecules.
