Answer:
k = 0.0901 yrs⁻¹
Explanation:
1st order decay is defined by the equation A = A₀e^-k·t. If A = A₀/2 and t represents the 1st half-life of the isotope then ...
t(1/2) = ln2/k = 0.693/k => k = 0.693/t(1/2) = 0.693/7.69yrs = 0.0901 yrs⁻¹
When the temperature is 23C, a bottle of gas has a pressure of 5.5atm.Assuming that the volume of the balloon remains constant, what will the
pressure be if the temperature is decreased to 18C?
Answer:
use the formula pressure 1 ÷ temperature 1 = pressure 2 ÷ temp 2
so your equation would look like this,
p2= p1(T2)÷ T1
so p2 =5.5(18)÷23
so it would be 4.304347826
round as you must
balance Fe+Cl2>FeCl3
Answer:
Explanation:
Fe + Cl2 ===> Fe Cl3 Make the Cls equal to a common denominatorFe + Cl2 ===> 2 FeCl3 There are 6 Cls on the rightFe + 3Cl2 ===> 2 FeCl3 Put a 2 in front of the Fe on the left2Fe + 3Cl2 ===> 2 FeCl3 And it is balanced.Identify the reactants and products in the following chemical equation: Zn +2HCl --> ZnCl2 + H2 *
20 points
A: Reactants: Zn & HCl Products: ZnCl2 & H2
B: Reactants: ZnCl2 & H2 Products: Zn & HCl
C: Reactants: Zn & H2 Products: ZnCl2 & HCl
Answer:
A.
Explanation:
zinc and hydrochloric acid reacts to form zinc chloride and hydrogen.
hope it helps. :)
Two gases helium and x are released from one end of an evacuated long cylinder at the same time if it takes helium atoms 3 times faster than gas X to effuse from one end. What is gas X?
Answer:
Hypoflorous acid, HOF
Explanation:
From the question, we're told that the helium atoms effuses 3 times than the said gas X.
We can determine the rate of effusion by using the formula
r is inversely proportional to 1/√M, where M is the molecular mass of the gas.
And also,
r is inversely proportional to 1/t, where t is the time taken for effusion.
From both formulas I listed, we can conclude that t is directly proportional to √M. And thus we proceed.
The molecular mass of Helium is 4.
tHe = tX/3, where tx is the time taken for the unknown gas X
As of yet, we don't know the molecular mass of X. Next, we say that
tX/tHe =√Mx/MHe
3 = √Mx/4
If we square both the sides, to remove the square root, we have
9 = Mx/4
Mx = 36
The molecular mass of the unknown gas X is 36.
2-methyl-2-butene + hydrogen chloride
This is an electrophilic addition of a hydrogen halide to an alkene.
The pi bond is attacked by the electrophilic H⁺ from the H⁺Cl⁻, resulting in the loss of the double bond and the formation of a tertiary carbocation on C2. A less stable carbocation intermediate with the positive charge on C3 is also formed.
The nucleophilic Cl⁻ then attacks the carbocations, forming the haloalkane products. The major product will be 2-chloro-2-methybutane, where the Cl is bonded to the most substituted C (Markovnikov's rule). The minor product, if you have to worry about it, will be 2-chloro-3-methylbutane. The major product has no stereoisomers to worry about as it's achiral.
The attached image shows the scheme of this reaction. Only the major product is shown.
In a titration of nitrous acid with NaOH, the pH of the solution is 3.14 when the moles of HNO2 and the moles of NO2-- are equal. What is the Ka of nitrous acid?
Answer:
[tex]Ka=3.98x10^{-4}[/tex]
Explanation:
Hello there!
In this case, since the modelling of titration problems can be approached via the Henderson-Hasselbach equation to set up a relationship between pH, pKa and the concentration of the acid and its conjugate base, we can write:
[tex]pH=pKa+log(\frac{[NO_2^-]}{[HNO_2]} )[/tex]
Whereas the pH is given as 3.14 and the concentrations are the same, that is why the pH would be equal to the pKa as the logarithm gets 0 (log(1)=0); thus, we can calculate the Ka via:
[tex]Ka=10^{-pKa}=10^{-3.14}\\\\Ka=3.98x10^{-4}[/tex]
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Mixture of water and LEAD SULPHATE is an example of Homogeneous mixture Select one : True O False
Answer:
False
Explanation:
Lead sulfate is insoluble in water and sinks in water
(sorry if it's wrong)
Calculate the pH of a solution prepared by dissolving 1.60 g of sodium acetate, CH3COONa, in 50.0 mL of 0.10 M acetic acid, CH3COOH(aq). Assume the volume change upon dissolving the sodium acetate is negligible. Ka of CH3COOH is 1.75 x 10^-5.
Answer:
pH = 5.35
Explanation:
Given 1.60 grams sodium acetate (NaOAc(aq))*** added to 50ml of 0.10M acetic acid (HOAc(aq)) solution.
Applying common ion effect keeping in mind that the addition of NaOAc provides the common-ion (OAc⁻).
HOAc(aq) ⇄ H⁺(aq) + OAc⁻(aq)
I 0.10m 1.32 x 10⁻³M ≈ ∅M* (1.6g/82.03g/mol) / 0.050L = 0.39M
C -x +x 0.39M + x ≈ 0.39M**
E 0.10M - x x 0.39M
≈ 0.10M
Ka = [H⁺][OAC⁻]/[HOAC] => [H⁺] = Ka·[HOAc] / [OAc⁻]
[H⁺] = (1.75 X 10⁻⁵)(0.10) / (0.39) = 4.5 x 10⁻⁶M
∴ pH = -log[H⁺] = -log(4.5 x 10⁻⁶) = -(-5.35) = 5.35
_______________________________________________
* [H⁺] before adding NaOAc = SqrRt(Ka · [HOAc]) = SqrRt(1.75 x 10⁻⁵· 0.10) = 1.32 x 10⁻³M. Since this concentration value is so small, the initial [H⁺] is assumed to be zero molar (∅M).
** The added [H⁺] is negligible and dropped in the ICE table. That is, adding ~[H⁺] in the order of 10⁻³M does not change the H⁺ ion concentration sufficiently to affect problem outcome and is therefore dropped in the ICE table.
*** Acetic Acid and Sodium Acetate are frequently written HOAc and NaOAc where the OAc⁻ anion is the acetate ion (CH₃COO⁻) for brevity.
The pH of the solution measures the acid of the liquid throughout the molar concentration of hydrogen ions in a solution.
[tex]\bold{CH_3COONa \ mass = 1.60\ g}\\\\[/tex]
Solution Volume (V) [tex]=50.0\ mL =0.05\ L\\\\[/tex]
[tex]\bold{CH3COONa \ molarity =0.10\ M }[/tex]
[tex]\bold{\text{Calculating the CH3COONa moles} =\frac{mass}{molar\ mass}}[/tex]
[tex]= \frac{1.60\ g}{82.03\frac{g}{mol}} \\\\=0.0195\ mol\\\\[/tex]
[tex]\bold{M = \frac{ \text{amount of solute moles} } { \text{solution volume in L} }}[/tex]
[tex]= \frac{0.0195\ mol}{0.05\ L}\\\\ =0.39\ M[/tex]
Using Henderson Hasselbach equation:
[tex]\bold{pH = -\log K_{a} + \log{[salt]}{[acid]}}\\\\[/tex]
[tex]=\bold{ -\log (1.75\times 10^{-5}) + \log ( \frac{0.39}{0.10}) }\\\\=\bold{ 4.757 + \log (3.9)}\\\\=\bold{ 4.757 + 0.5910}\\\\=\bold{ 5.348}\\\\=\bold{ 5.35}\\[/tex]
So, the final answer is "5.35".
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When a thermometer is heated, the red liquid inside the thermometer moves up. This is mainly because:
A. The red liquid is thin.
B. The molecules of the liquid move faster and get a little further apart.
C. Hot liquid is lighter.
D. The glass of the thermometer gets hot.
The thermometers with red liquid usually depicts a kerosene based column with red dye. It is more safe than mercury thermometer. The red liquid inside the thermometer moves up due to the molecules of the liquid move faster and get a little further apart. The correct option is B.
What is thermometer?The device which is used to measure the temperature is defined as the thermometer. It can measure the temperature of a solid such as food, a liquid like water and a gas like air.
The thermometers which are developed for clinical purposes are called clinical thermometers. It can also measure the temperature of human body. It is a long narrow glass tube which contain a bulb and consists of mercury at the end.
When a thermometer is heated, the molecules present in the liquid inside the thermometer get a little further apart. Because the liquid takes up more space. So the red line moves up in the tube.
Thus the correct option is B.
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What is total distance traveled?
What is the displacement (change in positions)
Answer:
Exercise 1
a) 140 m
b) 100 m
c) 180 m
d) 140 m
Exercise 2
a) 20 yards
b) 30 yards
c) 20 yards
d) 55 yards
Exercise 3
a) 11 Kilometers
b) 7 Kilometers
Explanation:
Exercise 1
Distance from B to C = 140 m
Distance from to D = 100 m
Total distance = 100+40+40 = 180 m
Total displacement i.e. distance between A and D is 140 m
Exercise 2
a) Distance from B to C = 35 -15 = 20 yards
b) Distance from C to D = 5 + 35 = 30 yards
c) Distance from B to D = 5 + 15 = 20 yards
d) Displacement = 5 + 50 = 55 yards
Exercise 3
a) The total distance travelled = 5 + 2 + 4 = 11 Kilometers
b) Displacement = 5-2 + 4 = 7 Kilometers
How many grams of iron contain 4.06X10^24 atoms of iron?
We have that the grams of iron contained 4.06X10^24 atoms of iron is
g= 376.6g
From the question we are told
How many grams of iron contain 4.06X10^24 atoms of iron?
Generally the equation for the Moles of Iron is mathematically given as
[tex]M=\frac{4.06x10^24}{6.02x10^23} \\\\M=6.744moles[/tex]
Therefore
Where Molar mass of Iron =55.845
Generally the equation for the mass is mathematically given as
g= 6.744 x 55.85
g= 376.6g
Therefore
the grams of iron contained 4.06X10^24 atoms of iron is
g= 376.6g
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what is acid by Lewis in science
A Lewis acid is a substance that accepts a pair of electrons to form a covalent bond. A Lewis base is a substance that donates a pair of electrons to form a covalent bond. So, a Lewis acid-base reaction is represented by the transfer of a pair of electrons from a base to an acid.
Which material is likely to slow the flow of electric charges the most? Explain.
Answer:
copper hiiiiiiiiiiiii
Which substance has the highest ph?
A. Tomato
B. Unpolluted rainwater
C. Ammonium hydroxide
D. Orange juice
Answer:
c ammonium hydroxide nh4oh has higher ph value and its a base
plz mark me branliest
Answer:
c) ammonium hydroxide
Explanation:
ammonium hydroxide nh4oh has higher ph value, and it is an alkaline
Calculate the pH of a solution with [H+]=1.45x10-10 . Is the solution acidic or basic
Answer:
So basicly it is basic
Explanation:
Take the -logarithm of the concentration of hydrogen ions that are in the solution: pH=−log(1×10−8M)=8. Therefore, the pH of the solution is 8
how can two rocks made by the same process be so different in color
Answer: Although the rocks of the produced by similar processes but their chemical composition may vary dependent upon the type of mineral present in these rocks so the color of the rock also varies depending upon the mineral composition.
Explanation:
The rocks are made by basic steps like disintegration of parent rock material, erosion, crystallization, metamorphism, and sedimentation. These basic steps are common in same kind of rocks but their color may vary because of the mineral composition in them for example, Rhyolite is of light colored because of the presence of quartz mineral present in it.
what are the two changes of state occurs during distillation
Answer:
The changes of state occur during distillation are boiling followed by condensation. The liquid is converted into its vapor phase at its boiling point and the vapor is then condensed back to liquid on cooling.
Explanation:
Heart me pls
What is the IUPAC name for the compound shown?
How many moles are in 4.28 x 1023 atoms of carbon?
0.711 moles C
General Formulas and Concepts:Math
Pre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to RightChemistry
Atomic Structure
Reading a Periodic TableMolesAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Stoichiometry
Using Dimensional AnalysisExplanation:Step 1: Define
[Given] 4.28 × 10²³ atoms C
[Solve] moles C
Step 2: Identify Conversions
Avogadro's Number
Step 3: Convert
[DA] Set up: [tex]\displaystyle 4.28 \cdot 10^{23} \ atoms \ C(\frac{1 \ mol \ C}{6.022 \cdot 10^{23} \ atoms \ C})[/tex][DA] Divide [Cancel out units]: [tex]\displaystyle 0.710727 \ moles \ C[/tex]Step 4: Check
Follow sig fig rules and round. We are given 3 sig figs.
0.710727 moles C ≈ 0.711 moles C
11 D. Organism 4 When Charles Darwin observed finches on the Galapagos Islands, he noted differences in the shapes of birds' beaks. redeater bexl, Leal, and fruit estet Ceci este Soalanxei celer A 0 If there is a two-year drought that kills off many seed and fruit plants, which finch species have traits that could make them more successful? A. A and B B. A and C C. B and C D. C and D
chemical equation of sodium carbonate on hydrochloric acid
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Answer: Na2CO3 + 2 HCl → 2 NaCl + H2CO3
I hope this helped!
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The body system responsible for breaking down food and absorbing nutrients is the ____
a
circulatory system
b
respiratory system
c
excretory system
d
digestive system
Answer:
d
digestive system
Explanation
5. Element X exists as diatomic molecules.
In which group of the Periodic
Table is X placed?
A. Group O
B.
Group I
C.
Group II
D.
Group VII
Element X Exists as diatomic molecules . In which group of the Periodic Table is X placed ?
Group VII
Group VII - elements are Fluorine , Chlorine , Bromine and Iodine .
They exist in diatomic molecules as F2 , Cl2 , Br2 and I2 .
Our most recent mass extension happened about 65million years ago. Describe the effects of this event.
Answer:
To explain what caused this mass extinction, scientists have focused on events that would have altered our planet's climate in dramatic, powerful ways. The leading theory is that a huge asteroid or comet slammed into Earth 65 million years ago, blocking sunlight, changing the climate and setting off global wildfires.
What is the density at STP of the gas sulfur hexafluoride, SF6?
O 3.93 x 1024 g/L
O 0.153 g/L
O 6.52 g/L
O 3270 g/L
Answer:
Explanation:
There is a formula for this:
M = DRT/P where M = molar mass. This just derived from PV = nRT where you say n = grams/molar mass. However, just with this formula, we can get D which is density at STP (1 atm and 273K). We find that D = 6.52g/L.
Biological membranes are selectively permeable, allowing certain molecules to cross the membrane, but not others. Classify the molecules or ions depending on how they cross a biological membrane. Note that some of these examples may also utilize active transport to traverse a membrane. However, this question is limited to passive transport processes only. Match the followings with each others
a. Simple Diffusion
b. Facilitated Diffusion
1. steroid hormones
2. K+
3. N2
4. Glucose
Answer:
Following are the solution to these question:
Explanation:
Simple diffusion implies which molecules can move across a cell membrane instead of using the incorporated protein structure channels. Its flow of molecules across these canals is enabled by diffusion. It has steroid hormones and N2.
Facilitated diffusion of molecules via cell membranes, or active transportation, which would be the random mass transit process of molecules or ions via unique cellular membranes from the transmembrane. It has K+ and Glucose.
Help for number 9 Please!
Answer:
A..............................
Calculate the grams of solute in each of the following solution: 278 mL of 0.038 M Fe2(SO4)3
Answer: 4.22 grams of solute is there in 278 ml of 0.038 M [tex]Fe_2(SO_4)_3[/tex]
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.
[tex]Molarity=\frac{n}{V_s}[/tex]
where,
n = moles of solute
[tex]V_s[/tex] = volume of solution in L
Now put all the given values in the formula of molality, we get
[tex]0.038M=\frac{n}{0.278L}[/tex]
[tex]n=0.0105mol[/tex]
mass of [tex]Fe_2(SO_4)_3[/tex] = [tex]moles\times {\text {Molar Mass}}=0.0105\times 399.88g/mol=4.22g[/tex]
Thus 4.22 grams of solute is there in 278 ml of 0.038 M [tex]Fe_2(SO_4)_3[/tex]
water from a town is suspected to contain chloride ions but not sulphate ions . describe how the presence of the chloride ions in the water can be shown
Answer:
See Explanation
Explanation:
We can establish that there are chloride ions present in water if we add dilute trioxonitrate V acid to a sample of the water in drops followed by aqueous silver trioxonitrate V.
If a white precipitate is observed and the precipitate is found to be soluble in excess aqueous ammonia solution, then we can confirm the presence of chloride ion in the water.
If there is sufficient water in the reaction system, how many grams of KOH can be produced from 22.2 g of K?
Answer: 31.9 g of KOH can be produced from 22.2 g of KOH
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} K=\frac{22.2g}{39g/mol}=0.57moles[/tex]
[tex]2K+2H_2O\rightarrow 2KOH+H_2[/tex]
According to stoichiometry :
2 moles of [tex]K[/tex] produce = 2 moles of [tex]KOH[/tex]
Thus 0.57 moles of [tex]K[/tex] will produce=[tex]\frac{2}{2}\times 0.57=0.57moles[/tex] of [tex]KOH[/tex]
Mass of [tex]KOH=moles\times {\text {Molar mass}}=0.57moles\times 56g/mol=31.9g[/tex]
Thus 31.9 g of KOH can be produced from 22.2 g of KOH