Answer:
oxygen
Explanation:
I dont know if you still need it but here it is
A chemist must prepare 650.0mL of sodium hydroxide solution with a pH of 13.90 at 25°C. He will do this in three steps:
Answer:
1. Weigh 3.27 ×10⁻⁴ ng of NaOH in a special balance for weighing in nanograms
2. Measure a volume of 650 mL in a test tube
3. Make the solution by mixture
Explanation:
NaOH is a strong base. As every strong base, can be completely dissociated:
NaOH → Na⁺ + OH⁻
If pH is 13.90, we can calculate the [OH⁻], so we would know the molarity of NaOH.
1 mol of NaOH can generate 1 mol of OH⁻
[OH⁻] = 10⁻¹³'⁹ = 1.26×10⁻¹⁴ M
In conclussion, molarity of NaOH is 1.26×10⁻¹⁴ M
M = moles of NaOH / volume of solution
We convert the volume from mL to L
650 mL . 1 L /1000mL = 0.650 L
Moles of NaOH = 0.650 L . 1.26×10⁻¹⁴ M = 8.18×10⁻¹⁵ moles
We convert the moles to mass, to determine the grams:
8.18×10⁻¹⁵ moles . 40 g/mol = 3.27 ×10⁻¹³ g
We can convert the grams to ng = 3.27 ×10⁻⁴ ng
A gas occupies 1.00 L at 273 K. What is the volume at 606 °C?
Answer:
3.22 L
Explanation:
0.00 C = 273 K
k = C +273
606 K + 273 K = 879 K
879/273 = 3.219
V2 = 3.22 L
how the charge of an element is used to determine the chemical formula if the elements have equal and unequal charges.
Answer:
The charges are typically used to determine the mole ratio and composition of the individual atoms of elements in the compound
Explanation:
Take for instance the following compounds:
[tex]NaOH[/tex] and [tex]H_{2} O[/tex]
Na has a charge of +1 and OH -1. equal charge means equal composition.H has charge of +1 while O has charge of -2. The charges are unequal, so the mole ratio for conversion would require multiplication by 2...which makes H two atoms but oxygen one atom in the compound.I hope this helps.
round 77.682517 to four figures
How many degrees along its orbit does the Moon travel between new moons?
Answer:
The moon orbits quite fast: it moves about 0.5 degrees per hour in the sky. In 24hrs it moves 13 degrees. the moons observed motion eastward results from its physical motion of the moon along its orbit around the earth
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What element does this model represent?
A
Potassium
B
Sodium
C
Oxygen
D
Boron
The Jones family is expecting guests at any moment they spray room freshener in one corner of the kitchen to remove the strong foods smell The room spray quickly becomes evenly distributed throughout the room making the whole kitchen smell fresh what is happening in this system?
Answer: Entropy is increasing
Explanation:
How many grams of F are in 365 g CaF2 ?
Answer:
177 grams
Explanation:
moles of CaF₂ = [tex]\frac{mass}{molar mass}[/tex] = [tex]\frac{365}{78}[/tex] = 4.67949
moles of F-atom = 2×moles of CaF₂ = 2×4.67949 = 9.35898
(mol)×(molar mass)= 9.35898×19 = 177.82062
Therefore, 177 grams of F are in the mixture.
To make a new solution, 35.0 mL of a 12.0 M HCl stock solution is diluted to a volume of 1.20 L. What is the concentration of the new solution?
Answer:
m1v1=m2v2 change 35 ml to l = 0.035L
12*0.035 = M2*1.20
Solve for M2 = 0.35M
Explanation:
A gas was trapped in a container containing 10mL of air at a pressure of 1.0 atm. What will be the new volume,if the pressure is changed to 5 atm at the same temperature?
Answer:
The answer is 2 mLExplanation:
The volume of the gas can be found by using the formula for Boyle's law
[tex]P_1V_1 = P_2V_2[/tex]
where
P1 is the initial pressure
P2 is the final pressure
V1 is the initial volume
V2 is the final volume
Since we are finding the new volume
[tex]V_2 = \frac{P_1V_1}{P_2} \\[/tex]
We have
[tex]V_2 = \frac{10 \times 1}{5} = \frac{10}{5} \\ [/tex]
We have the final answer as
2 mLHope this helps you
4.60 g of 3-hexanol were obtained from 5.33 g of hex-3-ene. Determine the percentage yield of 3-hexanol. a Determine the moles of hex-3-ene, , used in the experiment. (To avoid introducing rounding errors on intermediate calculations, enter your answer to four significant figures.)
Answer:
Explanation:
C₆H₁₂ + H₂O = C₆H₁₃OH
hexene hexanol
1 mole 1 mole
Mol weight of hexene = 84
Mol weight of hexanol = 102
5.33g of hexene = .06345 moles
4.6 g of hexenol = .0451 moles
percentage yield of hexanol
= .0451 x 100 / .06345
= 71.07 %
Moles of hexene used = .0451 moles
How do you know that K, an alkali metal is very reactive?
a. It conducts heat
b. It conducts electricity
C. It is a soft and shiny metal
d. It contains one valence electron
Answer:
d. It contains one valence electron.
Since, potassium has one valence electron so it can easily donate one electron during chemical reaction.
Imagine an element that has 15 protons, 16 neutrons, and 18 electrons. Which of the following would NOT be considered an isotope of this element? *
15 protons, 16 neutrons, and 15 electrons
15 protons, 17 neutrons, and 15 electrons
15 protons, 15 neutrons, and 18 electrons
Answer:
Explanation:
Option 1 15. Proton 16 neutron 15 electron
Isotopes have same atomic no but different atomic mass
why dose sodium have the same dot diagram as lithium
Answer:
They are in the same group on the periodic table indicating that they have the same number of valence electrons.
Explanation:
Which of the following is a characteristic of living things.
1. They obtain and use material and energy.
2. They grow & develop 3They respond to their environment.
4. They are made up of complex & organized cells
5. All the above are characteristics of living things
Answer:
I would say all of the above
Explanation:
I say this because we use material and energy, we grow and develop, we are made up of cells, and we respond to the environment.
Specialist species can respond more easily to changing environmental conditions tan can generalist species OTrue O False
Answer:
false
Explanation:
It would take more than 2___ wind turbines to replace coal power plants worldwide
Answer:
2,000,000
Explanation:
Answer:
yeah 2,000,000
Explanation:
A 22.60 gram sample of chromium is heated in the presence of excess chlorine. A metal chloride is formed with a mass of 68.83 g. Determine the empirical formula of the metal chloride.
Answer:
CrCl₃.
Explanation:
From the question given above, the following data were obtained:
Mass of chromium (Cr) = 22.60 g.
Mass of metal chloride = 68.83 g.
Empirical formula =.?
Next, we shall determine the mass of chlorine (Cl) in the metal chloride. This can be obtained as follow:
Mass of chromium (Cr) = 22.60 g.
Mass of metal chloride = 68.83 g.
Mass of chlorine (Cl) =.?
Mass of chlorine (Cl) = (Mass of metal chloride) – (Mass of chromium)
Mass of chlorine (Cl) = 68.83 – 22.60
Mass of chlorine (Cl) = 46.23 g
Finally, we shall determine the empirical formula for the metal chloride as follow:
Cr = 22.60 g.
Cl = 46.23 g
Divide by their molar mass
Cr = 22.60 / 52 = 0.435
Cl = 46.23 / 35.5 = 1.302
Divide by the smallest
Cr = 0.435 /0.435 = 1
Cl = 1.302 /0.435 = 3
The empirical formula for the metal chloride is CrCl₃
Iodine – 125 emits gamma rays when it decays to Tellerium-125 and has a half-life of 60 days. If a 0.020 g pellet of iodine – 125 is implanted into a prostate gland, how much iodine – 125 remains there after one year
Answer:
0.0003125 g
Explanation:
Given data:
Half life of iodine-125 = 60 days
Mass of iodine pellet = 0.020 g
Mass of iodine remain after one year = ?
Solution:
one year = 365 days
Number of half lives = Time elapsed/ half life
Number of half lives = 365 days/ 60 days
Number of half lives = 6
At time zero = 0.020 g
At 1st half life = 0.020 g/2 = 0.01 g
At 2nd half life = 0.01 g / 2 = 0.005 g
At 3rd half life = 0.005 g/2 = 0.0025 g
At 4th half life = 0.0025 g / 2 = 0.00125 g
At 5tht half life = 0.00125 g / 2 = 0.000625 g
At 6th half life = 0.000625 g/ 2 = 0.0003125 g
In the diagram below, particles of the substance are moving from the liquid phase to the gas phi
they move from the gas phase to the liquid phase.
The gas and liquid are at
O equilibrium
a high vapor pressure.
a low vapor pressure.
zero vapor pressure.
Answer:
Equilibrium
Explanation:
Correct on edge 2020
Answer:
A - Equilibrium
Explanation:
For edge:)
How do you determine the uncertainty of a digital instrument?
Which reaction product (A or B) is more likely to form in the epoxide ring opening reaction? Consider resonance structures.
Answer:
Reaction product A is more likely to form in the epoxide ring-opening reaction
Explanation:
The diagram for the reaction can be seen in the image attached below.
An epoxide is any class of organic compound, cyclic ethers, having a three-membered ring; they are usually prepared by selective oxidation of alkenes or by ring-closure of halohydrins(any class of organic compound having a hydroxyl functional group and a halogen on neighboring carbon atom ) which are used in making plastic.
Calculate the mass of sodium acetate that must be added to 500.0 mL of 0.300 M acetic acid to form a pH
Answer:
22.4 g
Explanation:
Calculate the mass of sodium acetate that must be added to 500.0 mL of 0.300 M acetic acid to form a pH = 5.00 buffered solution.
Step 1: Given data
Volume of solution: 500.0 mL
[acetic acid]: 0.300 M
pH = 5.00
pKa of acetic acid: 4.74
Step 2: Calculate the concentration of sodium acetate
We will use the Henderson-Hasselbach equation.
pH = pKa + log [sodium acetate]/[acetic acid]
5.00 = 4.74 + log [sodium acetate]/0.300 M
[sodium acetate] = 0.546 M
Step 3: Calculate the moles of sodium acetate
We have 500.0 mL of a 0.546 M sodium acetate solution
0.5000 L × 0.546 mol/L = 0.273 mol
Step 4: Calculate the mass of sodium acetate
The molar mass of sodium acetate is 82.03 g/mol.
0.273 mol × 82.03 g/mol = 22.4 g
Explain how cells are the basic unit of all living things
Answer:A cell is the smallest unit of a living thing. A living thing, whether made of one cell (like bacteria) or many cells (like a human), is called an organism. Thus, cells are the basic building blocks of all organisms. ... Several systems that function together form an organism (like a human being).
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How many moles of H2 can be formed if a 2.97 g sample of Mg reacts with excess HCl?
The number of moles of H₂ formed when 2.97 g sample of Mg reacts with excess HCl is 0.122 moles
To determine the number of moles of H₂ that can be formed if 2.97 g sample of Mg reacts with excess HCl,
First, we will write a balanced chemical equation for the reaction
Mg + 2HCl → MgCl₂ + H₂
From the reaction above,
It means that 1 mole of Mg will react with 2 moles of HCl to produce 1 mole of MgCl₂ and 1 mole of H₂
Now, we will determine the number of moles of Mg present in the given sample.
From the question,
Mass of Mg = 2.97 g
Using the formula
[tex]Number \ of \ moles = \frac{Mass}{Molar \ mass}[/tex]
Molar mass of Mg = 24.305 g/mol
∴ [tex]Number \ moles \ of \ Mg = \frac{2.97}{24.305}[/tex]
Number of moles of Mg in the sample = 0.122 moles
Since, 1 mole of Mg will react with 2 moles of HCl to produce 1 mole of MgCl₂ and 1 mole of H₂
∴ 0.122 moles of Mg will react with excess HCl to produce 0.122 moles of H₂
Hence, the number of moles of H₂ formed when 2.97 g sample of Mg reacts with excess HCl is 0.122 moles
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What are most membranes made up of?
layers of ducts
layers of epithelial tissue
layers of bursae
Answer:
layers of epithelial tissue
Answer:
It's B
Explanation:
the equilibrium constant, K, is greater than one. The stronger acid in this system is ___________ and the weaker base is ____________.
The question is incomplete; the complete question is;
For the following reaction:
H2CO3 + S2- ---------> HCO3- + HS-
The equilibrium constant is greater than one. The strongest acid in this system is ___________ and the weakest base is ____________.
A) H2CO3 and HS-
B) S2- and HS-
C) HCO3- and S2-
D) HS- and S2-
E) H2CO3 and HCO3-
Answer:
H2CO3 and HS-
Explanation:
According to the Brownstead- Lowry theory of acids and bases, an acid is a proton donor while a base is specie that accepts protons.
A strong acid has a greater tendency to donate protons. If we look at the reaction, H2CO3 has the greatest ability to donate protons hence it is the strongest acid.
On the other hand, HS- has the least ability to accept protons so it is the weakest base.
Determine the approximate density of a high-leaded brass that has a composition of 60.5 wt% Cu, 34.5 wt% Zn, and 5.0 wt% Pb. The densities of Cu, Zn, and Pb are 8.94, 7.13 and 11.35 g/cm3, respectively.
Answer:Approximate density of the high-leaded brass(alloy) =8.306g/cm³
Explanation:
The density of an alloy is its mass (100g) divided by its volume
Therefore we have that the alloy (high-leaded brass) has a composition of
60.5 wt% Cu with density 8.94g/cm3
34.5 wt% Zn, wth densty 7.13g/cm3
5.0 wt% Pb with densty g/cm3
The total volume of the alloy will be the mass / density of ts composition given as :
60.5gCu/DCu + 34.5gZn/DZn + 5.0gPb/Dpb
= 60.5/8.94 + 34.5/7.13+ 5.0/11.35
= 6.76 cm³ + 4.838 cm³+0.4405 cm³ = 12.0385cm³
Approximate density of the high-leaded brass(alloy) = 100g/ 12.0385cm³ =8.306g/cm³
a mixture of CaCO3 and CaO has a mass of 3.250g. After heating, the mass of the sample is reduced to 2.664g. What is the mass percent of CaCO3 in the mixture?
Answer:
40.92%
Explanation:
CaCo₃(s)-->CaO(s)+CO₂(g)
mass of Co2(g)= 1.33grams
mass of CaO(s)=(3.25-1.33)=1.92grams
mass % of CaCO₃ = [tex](\frac{1.33}{3.25} )[/tex]×100%
40.92%
what is listed on the right side of a chemical equation
Explanation:
The substances that "go in" to a chemical reaction are called the reactants (by convention these are usually listed on the left side of a chemical equation), and the substances found that "come out" of the reaction are known as the products (by convention these are usually found on the right side of a chemical equation
Answer: The reactants that go into the chemical reaction are on the left of the equation. The substances that come out of the chemical reaction are usually on the right side of the equation.
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