Answer:
True
Explanation:
hope this helps mate
Iodine-131 is administered orally in the form of NaI(aq) as a treatment for thyroid cancer. The half-life of iodine-131 is 8.04 days. If you begin with 34.7 mg of this isotope, what mass remains after 8.52 days have passed
Answer:
16.6 mg
Explanation:
Step 1: Calculate the rate constant (k) for Iodine-131 decay
We know the half-life is t1/2 = 8.04 day. We can calculate the rate constant using the following expression.
k = ln2 / t1/2 = ln2 / 8.04 day = 0.0862 day⁻¹
Step 2: Calculate the mass of iodine after 8.52 days
Iodine-131 decays following first-order kinetics. Given the initial mass (I₀ = 34.7 mg) and the time elapsed (t = 8.52 day), we can calculate the mass of iodine-131 using the following expression.
ln I = ln I₀ - k × t
ln I = ln 34.7 - 0.0862 day⁻¹ × 8.52 day
I = 16.6 mg
Francine makes several measurements of the mass of a metal block. The data set is shown in the table below.
Measurement
Mass of metal block (g)
1
20.73
2
20.76
3
20.68
4
20.75
After analyzing this data set, Francine calculates a value of 20.73 g.
Which of these characteristics has been calculated?
mean
median
mode
range
Answer:
Mean
Explanation:
The mean of a series of measurements is calculated when all the measurements are added up and then divided by the number of measurements taken, as follows:
Sum of Measurements = 20.73 + 20.76 + 20.68 + 20.75 = 82.92As there are 4 measurements, the mean is:
Mean = 82.92 / 4 = 20.73Answer:
A
Explanation:
Upon decomposition, a sample of sodium bicarbonate produces 0.0118 g of sodium carbonate, Na2CO3. How many grams of water does it produce
Answer:
2.00 × 10⁻³ g
Explanation:
Step 1: Write the balanced decomposition reaction
2 NaHCO₃ ⇒ Na₂CO₃ + CO₂ + H₂O
Step 2: Calculate the moles corresponding to 0.0118 g of Na₂CO₃
The molar mass of Na₂CO₃ is 105.99 g/mol.
0.0118 g × 1 mol/105.99 g = 1.11 × 10⁻⁴ mol
Step 3: Calculate the moles of H₂O produced with 1.11 × 10⁻⁴ moles of Na₂CO₃
The molar ratio of Na₂CO₃ to H₂O is 1:1. The moles of H₂O produced are 1/1 × 1.11 × 10⁻⁴ mol = 1.11 × 10⁻⁴ mol.
Step 4: Calculate the mass corresponding to 1.11 × 10⁻⁴ moles of H₂O
The molar mass of H₂O is 18.02 g/mol.
1.11 × 10⁻⁴ mol × 18.02 g/mol = 2.00 × 10⁻³ g
Phosphorus -32 is a commonly used radioactive nuclide in biochemical research, particularly in studies of nucleic acids. The half-life of phosphorus-32 is 14.3 days. What mass of phosphorus-32 is left from an original sample of 175 mg of Na332PO4 after 35.0 days
Answer: The mass of P-32 left from the original sample is 32.07 mg
Explanation:
All radioactive decay processes follow first-order reactions.
Calculating rate constant for first order reaction using half life:
[tex]t_{1/2}=\frac{0.693}{k}[/tex] .....(1)
[tex]t_{1/2}[/tex] = half life period = 14.3 days
k = rate constant = ?
Putting values in equation 1:
[tex]k=\frac{0.693}{14.3days}\\\\k=0.0485days^{-1}[/tex]
The integrated rate law equation for first-order kinetics:
[tex]k=\frac{2.303}{t}\log \frac{a}{a-x}[/tex] ......(2)
Given values:
a = initial concentration of reactant = 175 mg
a - x = concentration of reactant left after time 't' = ? mg
t = time period = 35.0 days
Putting values in equation 2:
[tex]0.0485days^{-1}=\frac{2.303}{35.0 days}\log (\frac{175}{a-x})\\\\\log (\frac{175}{a-x})=\frac{0.0485\times 35.0}{2.303}\\\\\log (\frac{175}{a-x})=0.737\\\\\frac{175}{a-x}=10^{0.737}\\\\a-x=\frac{175}{5.457}=32.07mg[/tex]
Hence, the mass of P-32 left from the original sample is 32.07 mg
What is homeostasis?
a.
production of urine.
b.
maintaining a stable internal environment.
c.
excretion of waste materials.
d.
none of the above.
Please select the best answer from the choices provided
Answer:
the tendency toward a relatively stable equilibrium between interdependent elements, especially as maintained by physiological processes.
Explanation:
Which pair of compounds has the same empirical formula?
1.
C2H2 and C6H6
2
C2H6 and C3H8
3.
CH3OH and C2H5OH
4.
CH3CHO and CH3COOH
Explanation:
Correct option is
B
CH
3
COOH
Empirical formula of Glucose C
6
H
12
O
6
= C
1
H
2
O
1
Now, Empirical formula of CH
3
COOH=C
1
H
2
O
1
As empirical formula is the simplest whole number ratio of number of different types of atoms present in the given molecular formula.
1,500 grams is equal to:
1.5 kg
1.5L
1.5 cm
all of the above
A chemist must prepare 900.0 mL of potassium hydroxide solution with a pH of 12.20 at 25°C.
He will do this in three steps:
• Fill a 900.0 mL volumetric flask about halfway with distilled water.
• Weigh out a small amount of solid potassium hydroxide and add it to the flask.
. Fill the flask to the mark with distilled water.
Calculate the mass of potassium hydroxide that the chemist must weigh out in the second step. Round your answer to 2 significant digits and put your answer in grams (g).
Answer:
0.80 g
Explanation:
First we calculate the required pOH from the given pH value:
pOH = 14 - pHpOH = 14 - 12.20 = 1.80Then we calculate the required concentration of OH⁻, using the pOH:
pOH = -log[OH⁻][OH⁻] = [tex]10^{-1.80}[/tex] = 0.0158 MAs the concentration of OH⁻ species is the sames as the concentration of KOH, we need to prepare 900 mL of a 0.0158 M KOH solution:
We calculate how many KOH moles are required, using the concentration and volume:
Converting 900 mL ⇒ 900 / 1000 = 0.900 Lmoles = 0.0158 M * 0.900 L = 0.01422 molFinally we convert 0.01422 moles of KOH to grams, using its molar mass:
0.01422 mol * 56 g/mol = 0.80 gHow can we protect space shuttles or astronauts from space radiation in the absence of the atmospheric layer?
What is the role of gravity in maintaining the atmospheric layer around the earth ?
Please put your answers with clear explanation.
Thank you !
Answer:Earth's protective magnetic bubble, called the magnetosphere, deflects most solar particles. ... The International Space Station cruises through low-Earth orbit, within Earth's protection, and the station's hull helps shield crew members from radiation too.☘
have a nice day
A molecule of composition is replicated in a solution containing unlabeled (not radioactive) GTP, CTP, and TTP plus adenine nucleoside triphosphate with all its phosphorus atoms in the form of the radioactive isotope 32P. Will both daughter molecules be radioactive
Answer:
Please find the complete question in the attached file.
Explanation:
It would only be radioactive if the DNA molecule that employed the poly-T rand as templates. Its other molecule of the daughter would not have been radioactive as it did not need dATP for its replication. While each strand of the second molecule includes t, simultaneous reproduction dATP from both daughter molecules is needed so that each of those is radioactive.
the density of gold is 19.3 g/ml. if you had a cube made of pure gold that weighs 58.1 pounds what would be the lengh of a side of this cube
Answer:
11.1 cm
Explanation:
First we convert 58.1 pounds into grams:
58.1 lb * [tex]\frac{453.592g}{1lb}[/tex] = 26353.69 gThen we calculate the volume of the gold cube, using the given density:
26353.69 g ÷ 19.3 g/mL = 1365.48 mL
1365.48 mL is equal to 1365.48 cm³.With the volume of a cube we can calculate the side length:
Length = ∛(1365.48 cm³) = 11.1 cmTwo planets have similar masses but differ in their distances from the Sun.
Which planet experiences a greater gravitational force with the Sun?
A. The planet that is smaller in volume
B. The planet that is larger in volume
C. The planet that is farther from the Sun
D. The planet that is closer to the Sun
Answer:
D. The planet that is closer to the Sun
what climate zone is asia?
Answer:
The Tundra Climate
Explanation:
:) hope this helps
If a solid line represents a covalent bond and a dotted line represents intermolecular attraction, which of the choices shows a hydrogen bond?
1. H−H
2. H4C⋯H−F
3. H3N⋯H−O−H
4. H2O⋯H−CH3
Answer:
3
Explanation:
Hydrogen bonding occurs between molecules in which hydrogen is bonded to a highly electronegative atom such as nitrogen, oxygen, chlorine, etc.
In option 3, the two compounds are H3N and H2O. In both molecules, hydrogen is directly attached to highly electro negative atoms(nitrogen and oxygen respectively). Hence, it is only in option 3 that we observe hydrogen bonding.
Its Acutally A Because if you use the type he used its not even the question
Explination
Im RIght
how many moles of H2o are equivelant to 97.3g h2o
Answer:
Number of mole in H2O = 5.4 moles
Explanation:
Given:
Mass of H2O = 97.3 gram
Find:
Number of mole in H2O
Computation:
We know that molar mass of H2O = 18 g/mole
So,
Number of mole = Given Mass / Molar mass
Number of mole in H2O = Mass of H2O / Molar mass of H2O
Number of mole in H2O = 97.3 / 18
Number of mole in H2O = 5.4055
Number of mole in H2O = 5.4 moles
2. Which of the following equations represents a neutralization reaction?
a. H2CO3 + H2O + CO2
b. 2H2O2 → 2H2O + O2
c. Ba(NO3)2 + K2CO3 →
BaCO3 + 2KNO3
d. HNO3 + NaOH → NaNO3 + H2O
Answer:
d. HNO3 + NaOH → NaNO3 + H2O
Explanation:
Hello there!
In this case, according to the given chemical reactions, it turns out necessary for us to recall the definition of neutralization reaction as those whereby an acid reacts with a base, that is why a, b and c are not within the aforementioned description.
In such a way, we infer the reaction is d. HNO3 + NaOH → NaNO3 + H2O since HNO3 is the acid and NaOH the base.
Regards!
help me plsssssssss.... im timed
Answer:
a
Explanation:
a
Answer:
B. Isotopes of the element.
Explanation:
Isotopes are basically atoms of the same element that contain the same number of protons, but a different number of neutrons.
If 0.5 L of O2(g) reacts with H, to produce 1 L of H2O(g), what is the volume of
H2O(g) obtained from 1 L of O2(g)?
-
0.5 L
2.5 L
2 L
1.5 L
Answer:
2 L
Explanation:
We'll begin by writing the balanced equation for the reaction. This is given below:
2H₂ + O₂ —> 2H₂O
From the balanced equation above, we can see clearly that 1 L of O₂ reacted to 2 L of H₂O.
This implies that 2 L of H₂O can be obtained by the reaction of 1 L of O₂.
Thus, option 3 gives the correct answer to the question.
How many moles of aluminum oxide are produced according to the reaction below given that you start with 40.0 grams of Al and 19.0 grams of O2?
Reaction: 4Al + 3O2 --> 2Al2O3
A. 0.185
B. 0.741
C. 5.00
D. 0.396
From the stoichiometry of the reaction, 0.74 moles of aluminium oxide is produced.
The equation of the reaction is;
4Al + 3O2 --> 2Al2O3
Number of moles of Al = 40.0/27 g/mol = 1.48 moles
Number of moles of O2 = 19.0 g/32 g/mol = 0.59 moles
Now;
4 mols of Al reacts with 3 moles of O2
1.48 moles of Al reacts with 1.48 moles × 3 moles/4 mols
= 1.11 moles
We can see that O2 is the reactant in excess.
Hence;
4 moles of Al produces 2 moles of aluminium oxide
1.48 moles of Al produces 1.48 moles × 2 moles/4 moles = 0.74 moles of aluminium oxide
Learn more about stoichiometry: https://brainly.com/question/9743981
The element tin has the following number of electrons per shell: 2, 8, 18, 18, 4. Notice that the number of electrons in the outer shell of a tin atom is the same as that for a carbon atom. Therefore, what must be true of tin
The question is incomplete, the complete question is:
The element tin has the following number of electrons per shell: 2.8. 18, 18, 4. Notice that the number of electrons in the outer shell of a tin atom is the same as that for a carbon atom. Therefore, what must be true of tin? Tin is a polar atom and can bind to other polar atoms. Tin has a high molecular weight to give tin-containing molecules greater stabilty. All of the above Tin conform single covalent bonds with other elements, but not double or triple covalent bonds Tincan bind to up to four elements at a time
Answer:
Tin can bind to up to four elements at a time
Explanation:
Certain important points were made in the question about tin and one of them is that tin is an element in the same group as carbon hence it has the same number of valence electrons as carbon.
Carbon is always tetra valent. The tetra valency of carbon is the idea that carbon forms four bonds.
If tin has the same number of valence electrons as carbon, then, tin can bind to up to four elements at a time
If the initial amount of indium-117 is 5.2 g, how much indium-117 is left in the body after 86 min
At STP, which gaseous sample has the same number
of molecules as 5.0 liters of O2 (g)?
A) 6.0 L of F2 (g)
B) 4.5 L of O2 (g)
C) 3.0 L of H2 (g)
D) 5.0 L of Cl2 (9)
Question 13 of 32
The pH of a sample of seawater is 8.0. What is the hydrogen ion concentration of seawater?
A. 8.0 M
B. 1 x 108 M
C. 6.0 M
D. 1 x 10-8 M
Answer:
D
Explanation:
How much energy is released when 2.25kg of water cools from 99.5°C to 4.2°C? 1000g=1kg; 1000J=1kJ; specific heat of water 4.184J/g°C. q=mc∆T
Answer:
897154.2 J
Explanation:
Applying,
q = mcΔT.............. Equation 1
Where q = amount of energy released, m = mass of water, c = specific heat capacity of water, ΔT = Change in temperature
From the question,
Given: m = 2.25 kg = 2250 g, c = 4.184 J/g°C, ΔT = (4.2-99.5) = -95.3°C
Substitute these values into equation 1
q = 2250(4.184)(-95.3)
q = -897154.2 J
q =
Hence the amount of heat released is 897154.2 J
Can you help ASAP? Thanks you.
Answer:
ok
Explanation:
How long does it take for water to boil?
Answer:
around 5-10 minutes it may take but the actual answer is when the temperature of water reaches 100°Celsius
Answer:
How Long Does It Take to Boil Water? To boil 1 liter of water (4 cups), it takes about 8 to 10 minutes in a pot on the stove with high heat and the lid on. 1 liter of water boils in an electric kettle in about 4 to 5 minutes. 1 liter of water boils in a microwave in about 3 to 4 minutes
have a great day
#brainlest
As a result of the particles in a gas being in constant motion, gas has a _______.
variable volume
variable Pressure
variable Shape
variable mass
Answer:
i think it's variable pressure
if not soo advance sorry :)
In which of the following molecules is hydrogen bonding likely to be the most significant component of the total intermolecular forces??
a. C6H13NH2
b. CH3OH
c. CH4
d. C5H11OH
e. CO2
Answer:
The given molecules are:
a. C6H13NH2
b. CH3OH
c. CH4
d. C5H11OH
e. CO2
Explanation:
The hydrogen bond is a weak electrostatic force of attarction that exists between covalently bonded hydrogen (of -OH or -NH2 or HF) with a highly electronegative atom like N,O and F.
Hydrogen bonding is of two types:
Intermolecular hydrogen bond (exists between two molecules)
Intramolecular hydrogen bond(exists within a molecule).
For example intermolecular hydrogen bond in water is shown below:
Among the given options,
a. C6H13NH2 has -NH2 linkage which leads to hydrogen bond formation.
b. CH3OH has -OH bond and it leads to hydrogen bond fomation.
d. C5H11OH has also -OH bond and it leads to hydrogen bond fomation.
Reamining molecules, CH4 and CO2 do not form hydrogen bond.
Hence, answer is:
options a,b,d.
Increasing the temperature of a particular liquid from 298 K to 318 K causes its vapor pressure to double. What is the enthalpy of vaporization of this liquid
Answer:
27.3 kJ/mol
Explanation:
Step 1: Given data
Temperature 1 (T₁): 298 KVapor pressure 1 (P₁): P₁Temperature 2 (T₂): 318 KVapor pressure 2 (P₂): 2 P₁Step 2: Calculate the enthalpy of vaporization of this liquid
We will use the Clausius–Clapeyron equation.
ln (P₂/P₁) = -ΔHvap/R × (1/T₂ - 1/T₁)
ln 2 = -ΔHvap/(8.314 J/K.mol) × (1/318 K - 1/298 K)
ΔHvap = 2.73 × 10⁴ J/mol = 27.3 kJ/mol
The limiting reactant in a chemical reaction is the reactant __________ Select one: A. for which you have the lowest mass in grams. B. which has the lowest coefficient in the balanced equation. C. which has the lowest molar mass. D. which is left over after the reaction has gone to completion. E. None of the above.
Answer:
i think its A
