Answer:
1 mole of platinum
Explanation:
To obtain the number of mole(s) of platinum present, we need to determine the empirical formula for the compound.
The empirical formula for the compound can be obtained as follow:
Platinum (Pt) = 117.4 g
Carbon (C) = 28.91 g
Nitrogen (N) = 33.71 g
Divide by their molar mass
Pt = 117.4 / 195 = 0.602
C = 28.91 / 12 = 2.409
N = 33.71 / 14 = 2.408
Divide by the smallest
Pt = 0.602 / 0.602 = 1
C = 2.409 / 0.602 = 4
N = 2.408 / 0.602 = 4
The empirical formula for the compound is PtC₄N₄ => Pt(CN)₄
From the formula of the compound (i.e Pt(CN)₄), we can see clearly that the compound contains 1 mole of platinum.
After a recrystallization, a pure substance will ideally appear as a network of __________. If this is not the case, it may be worthwhile to reheat the flask and allow the contents to cool more _________
Answer:
Large crystals
Slowly
Explanation:
Recrystallization is a procedure used to purify an impure compound in a solvent. The concept used here is that the solubility of most of the solids increases with increase in temperature.
Recrystallization is also called as method of fractional crystallization.
After a recrystallization, a pure substance will ideally appear as a network of large crystals. If this is not the case, it may be worthwhile to reheat the flask and allow the contents to cool more slowly.
An object has a mass of 72 kg. What is its weight?
Answer:Acceleration due to gravity on the moon is 1/6 times as that on the earth and we know that mass is property of the material it always remains same and weight is measure of gravitational force, hence
mass of object on moon is 60kg and weight =60g/6=10×10=100N
Explanation:
16. Using the average atomic masses given in the inside front cover of this book, calculate the indicated quantities.
d. the number of moles of cobalt represented by 5.99 x 1021 cobalt atoms e. the mass of 4.23 mol of cobalt
f. the number of cobalt atoms in 4.23 mol of cobalt
g. the number of cobalt atoms in 4.23 g of cobalt
Answer:
d. 9.95 × 10⁻³ mol
e. 249 g
f. 2.55 × 10²⁴ atoms
g. 4.32 × 10²² atoms
Explanation:
d. the number of moles of cobalt represented by 5.99 x 10²¹ cobalt atoms
We will use Avogadro's number: there are 6.02 × 10²³ atoms of cobalt in 1 mole of atoms of cobalt.
5.99 x 10²¹ atoms × 1 mol/6.02 × 10²³ atoms = 9.95 × 10⁻³ mol
e. the mass of 4.23 mol of cobalt
The molar mass of cobalt is 58.93 g/mol.
4.23 mol × 58.93 g/mol = 249 g
f. the number of cobalt atoms in 4.23 mol of cobalt
We will use Avogadro's number: there are 6.02 × 10²³ atoms of cobalt in 1 mole of atoms of cobalt.
4.23 mol × 6.02 × 10²³ atoms/1 mol = 2.55 × 10²⁴ atoms
g. the number of cobalt atoms in 4.23 g of cobalt
First, we will calculate the moles of cobalt using the molar mass of cobalt.
4.23 g × 1 mol/58.93 g = 0.0718 mol
Then, we will calculate the number of cobalt atoms using Avogadro's number.
0.0718 mol × 6.02 × 10²³ atoms/1 mol = 4.32 × 10²² atoms
When Elsa freezes things, is it an example of an exothermic or
endothermic reaction? Explain.
Answer:
endothermic reaction
Explanation:
When Elsa from Frozen freezes things, it is an example of an endothermic chemical reaction.
An endothermic involves a reaction in which heat is absorbed from the surrounding. Hence the surrounding becomes colder at the end of the the change.
So, Elsa draws heat from the environment and this causes the environment to be colder and things that are in contact with her.
Classify each of the following compounds as a strong acid, weak acid, strong base, or weak base, and write the Ka expression for any weak acid or weak base:
1. [ Select ] ["strong base", "weak base", "strong acid", "weak acid"] LiOH
2. [ Select ] ["weak acid", "strong acid", "strong base", "weak base"] HF
3. [ Select ] ["strong acid", "weak acid", "strong base", "weak base"] HCl
4. [ Select ] ["weak base", "strong base", "weak acid", "strong acid"] NH3
Ka expression: [ Select ] ["[H+][F-] / [HF]", "[Li+][OH-]/ [LiOH]", "[H+][Cl-} / [HCl]", "[NH4+] / [NH3]", "[HF] / [H+][F-}", "[LiOH] / [Li+][OH-]", "[HCl] / [H+][Cl-}", "none"]
Calculate the concentration of OHLaTeX: -? in a solution that has a concentration of H+ = 7 x 10LaTeX: -?6 M at 25°C. Multiply the answer you get by 1010 and enter that into the field to 2 decimal places.
Answer:
See explanation below
Explanation:
There are several ways to know if an acid or base is strong. One method is calculating the pH. If the pH is really low, is a strong acid, and if it's really high is a strong base.
However we do not have a pH value here.
The other method is using bronsted - lowry theory. If an acid is strong, then his conjugate base is weak. Same thing with the bases.
Now, Looking at the 4 compounds, we can say that only two of them is weak and the other two are strong compounds. Let's see:
LiOH ---> Strong. If you try to dissociate :
LiOH ------> Li⁺ + OH⁻ The Li⁺ is a weak conjugate acid.
HF -----> Weak
HF --------> H⁺ + F⁻ The Fluorine is a relatively strong conjugate base.
HCl -----> Strong
This is actually one of the strongest acid.
NH₃ ------> Weak
Now writting the Ka and Kb expressions:
Ka = [H⁺] [F⁻] / [HF]
Kb = [NH₄⁺] [OH⁻] / [NH₃]
Finally, to calculate the [OH⁻] we need to use the following expression:
Kw = [H⁻] [OH⁻]
Solving for [OH⁻] we have:
[OH⁻] = Kw / [H⁺]
Remember that the value of Kw is 1x10⁻¹⁴. So replacing:
[OH⁻] = 1x10⁻¹⁴ / 7x10⁻⁶
[OH⁻] = 1.43x10⁻⁹ M
And now, multiplying by 10¹⁰ we have:
[OH⁻] = 1.429x10⁻⁹ * 1x10¹⁰
[OH⁻] = 14.29Hope this helps
Strong acids and bases are those which completely ionized in body fluid, and weak acids and bases are those who does not completely ionized in body fluid.
Ka expression is used to differentiate between strong and weak acids.
Which are strong acids and base and weak acids and bases?LiOH - strong baseHF - weak acidHCl - strong acidNH3 - weak baseWhat are the Ka expression of the following?Weak acid – HF[tex]\bold{\dfrac{[H+][F-]}{[HF]}}[/tex]
Weak base – NH3[tex]\bold{\dfrac{[NH_4^+] [OH^-]}{[NH_3]} }[/tex]
Calculate the concentration of OH?Given, [tex]\bold{ [H^+]=1\times10^-^6\; at \;25^oC}[/tex]
We know, [tex]\bold{ [H^+]\times[OH^-]=1\times10^-^6\; at \;25^oC}[/tex]
[tex]\bold{[OH^-]=\dfrac{1\times10^-^1^4}{6.2\times10^-^6} = 1.43\times10^-^9}[/tex]
Now, multiplying the value by [tex]10^1^0[/tex]
[tex]\bold{( 1.429\times10^-^9) \times 1\times10^1^0= 14.29}[/tex]
Thus, the value is 14.29.
Learn more about acid and base, here:
https://brainly.com/question/10468518
Select the correct coefficients to balance the reaction given below.
__Al + ___O₂ → ____ Al₂ O₃
Answer:
4Al+3O2→2Al2O3
Explanation:
A change of state is a(n)
process.
A. irreversible
B. reversible
Answer:
Changes of states are reversible, you can go from a solid to liquid and liquid to solid.Answer:
Reversible
Explanation:
Changes of state are physical changes in matter. Common changes of the state include melting, freezing, sublimation, deposition, condensation, and vaporization.
Which element is classified as a transition metal?
A) lithium (Li)
B) zirconium (Zr)
C) tellurium (Te)
D) xenon (Xe)
Answer:
C) tellurium (Te) is the correct answer.
A 32.60 g sample of a solid is placed in a flask. Toluene, in which the solid is insoluble, is added to the flask so that the total volume of solid and liquid together is 51.00 mL . The solid and toluene together weigh 58.86 g . The density of toluene at the temperature of the experiment is 0.864 g/mL. What is the density of the solid?
Answer:
0.864 g/mL.
Explanation:
I hope this helps u! also have a great rest of your day!
Using your own words whats the difference between weather and climate
Answer:
Weather is at a specific place and time. Climate is over a period of time.
Explanation:
That is the difference
You have three BSA working solutions: 5ug/ul, 0.5 ug/ul, and 0.05 ug/ul. Each tube contains 500 ul of solution. How much of which concentration(s) would you pipet into three different centrifuge tubes so you end up with 20 ug, 2 ug, and 0.2 ug of BSA in each tube
Answer:
I would pipet 4 μl of each BSA work solution
Explanation:
To calculate the mass (in μg), we have to multiply the concentration C (in μg/ul) by the volume V (in μl):
C(μg/ul) x V( μl) = mass (μg)
We found the required volume for each solution, as follows:
5 μg/μl x V₁ = 20 μg ⇒ V₁ = 20 μg/(5 μg/μl ) = 4 μl
0.5 μg/μl x V₂ = 2 μg ⇒ V₂ = 2 μg/(0.5 μg/μl) = 4 μl
0.05 μg/μl x V₃ = 0.2 μg ⇒ V₃= 0.2 μg/(0.05 μg/μl) = 4 μl
Therefore, we need to pipet 4 μl of the solutions of concentrations 5μg/μl, 0.5 μg/μl, and 0.05 μg/μl to obtain the masses 20 μg, 2 μg, and 0.2 μg, respectively.
3. The doctor notices that Janet has long fingernails, and comments that fingernails grow at a rate (or
speed) of 2.50 cm / year. Convert this speed to kilometers / second. Show your work. (6 pts)
Answer:
7.93 × 10⁻¹³ km/s
Explanation:
Step 1: Given data
Rate of growth of the fingernails (r): 2.50 cm/year
Step 2: Convert "r" from cm/year to km/year
We will use the following conversion factors.
1 m = 100 cm1 km = 1000 m[tex]\frac{2.50cm}{year} \times \frac{1m}{100cm} \times \frac{1km}{1000m} = 2.50 \times 10^{-5} km/year[/tex]
Step 3: Convert "r" from km/year to km/s
We will use the following conversion factors.
1 year = 365 day1 day = 24 h1 h = 60 min1 min = 60 s[tex]\frac{2.50 \times 10^{-5} km}{year} \times \frac{1year}{365day} \times \frac{1day}{24h} \times \frac{1h}{60min} \times \frac{1min}{60s} = 7.93 \times 10^{-13} km/s[/tex]
2.50 cm/year is equal to 7.93 × 10⁻¹³ kilometers/second.
Which of the following has the largest atomic radius?
Answer:
b
Explanation:
If Juan had a glass of milk and dissolved 20g of chocolate milk powder into the milk, by how much will the mass of the milk go up by?
Answer:
20g or 0.2kg
Explanation:
this is because the mass of the powder is 20g and this will be added to the original mass of the milk causing it to increase by that amount
Answer: 20g
Explanation:
0
Which is not one of Earth's layers?
A А
crust
B)
inner core
mantle
D
ocean
The ocean is not a part of Earth's layers.
Answer:
Ocean
Explanation:
there is concern in health-related government agencies that the american diet contains too much meat, and numerous recommendations have been made urging people to consume more fruit and vegetables. one of the richest sources of vegetable protein is soy, available in many forms. among these is soybean curd, or tofu, which is a staple of many asian diets. chemists have isolated an anticancer agent called genistein from tofu, which may explain the much lower incidence of cancer among people in the far east. a valid lewis structure for genistein is
Answer:
Explanation:
The aim of this question is to draw the structure of genistein and determine the number of atoms with sp² hybridization in the molecule.
From the image below, we will see the lewis structure of genistein. From the image, the blue asterisk atoms are sp² hybridized and the red marked atoms are sp³ hybridized.
We will also notice that all the carbon atoms contain 3 σ-bonds with no lone pair of electrons.
Using the knowledge of Valence shell electron repulsion theory (VSEPR), the above-mentioned carbon atom is said to be sp²hybridized.
Also, the oxygen atoms which are doubly bounded contains 1 σ-bond and 2 lone pair electrons. These oxygen atoms are also sp² hybridized.
Finally, the singly bonded oxygen atom is composed of 2 σ-bonds and 2 lone pair electrons. This makes it to be sp³ hybridized.
Altogether, we have a total of 16 sp² hybridized atoms and 4 sp³ hybridized atoms.
LaKeisha is measuring the density of a solid piece of metal using the graduated cylinder method. She initially measures a volume of water in the cylinder to be 3.28 mL. After placing the metal into the graduated cylinder, the new volume was 8.72 mL. The mass of the metal was 42.26 g on a top loading balance.
Required:
What is the density of the metal calculated to the correct number of significant figures?
Answer: 7.77 g/ml
Explanation:
Volume of cylinder with only water = 3.28 mL
Volume of cylinder with water and metal = 8.72 mL
Volume of metal = (Volume of cylinder with water and metal ) -(Volume of cylinder with only water)
=8.72-3.28
=5.44 ml
Mass of metal = 42.26 g
Formula of Density = [tex]\dfrac{\text{Mass}}{\text{Volume}}[/tex]
i.e. the density of the metal = [tex]\dfrac{42.26}{5.44}\approx7.77\text{ g/ml}[/tex]
Hence, the density of metal = 7.77 g/ml
Which one has only 1 type of atom? compound element mixture solution
Answer:
look it updjk jkj vjx cv xckv
Explanation:
look it upvjcvjkcxjbvjkcvbjbcxkjvjdbfcvbdw uvd vjbvjfjv jdbv
Answer:
element :
a substance that is made up of only one type of atom
I hope it helps you ✌
A physical change does not involve a change in the substance’s chemical identity. Which of these statements describes a physical change?
Group of answer choices
A banana starts to smell as it ripens.
Onions taste sweeter after being cooked.
Aluminum cans get crushed before recycling.
Copper turns green when exposed to air.
Answer: the answer is C Aluminum cans get crushed before recycling.
Explanation:
Answer:
it will option C because it had no change in chemical reaction
Part I: SP3 Hybridization: B: Ethane Distance between C-C in ethane: ________________ Distance between H atoms in eclipsed conformation: ________________ Distance between H atoms in staggered conformation: ________________ Which is more stable (circle one): STAGGERED or ECLIPSED
Answer:
Distance between C-C in ethane- 1.54 Å
Distance between H atoms in eclipsed conformation-2.3 Å
Distance between H atoms in staggered conformation- 2.5 Å
Staggered conformation is more stable
Explanation:
The staggered conformation of ethane can be demonstrated as the most stable of conformation of ethane, because the angles between Carbon-Hydrogen bonds in both the front and back carbon atoms are maximized. This now minimizes the energy of this conformation compared to the eclipsed conformation.
Considering the eclipsed conformation, it is obvious that the electron densities on Carbon-Hydrogen bonds come very close together thereby bringing two C-H bonds into a dihedral angle of almost zero degrees. This causes their electron clouds to experience strong repulsion, thereby raising the molecules's total energy.
What is an ecosystem? ?
Answer:
An ecosystem is a community or group of living organisms that live in and interact with each other in a specific environment.
Explanation:
That's the most straight forward explanation I could come up with
A cylinder containing CH4, C2H6, and N2 has to be prepared in which the ratio of the moles of CH4 to C2H6 is 1.3 to 1. Available are (1) a cylinder containing a mixture of 70% N2 and 30% CH4, (2) a cylinder containing a mixture of 90% N2 and 10% C2H6, and a cylinder of pure N2. Determine the proportions in which the respective gases from each cylinder should be used
Answer:
The proportions in which the respective gases from each cylinder should be used; C1 : C2 : C3 = 1 : 2.308 : C3
Explanation:
Given that;
CH4 to C2H6 = 1.3 to 1
Cylinder 1 = 70% N2 and 30% CH3
Cylinder 2 = 90% N2 and 10% C2H6
Cylinder 3 = ( pure N2 ) = 100% N2
CH4 to C2H6 = (1.3 to 1)
we have CH4 and C2H6 in cylinder 1 and 2 only
we only have balance material in c1 and c2
Now, Let x be from cylinder and ( 1-x ) be from cylinder 2
so, 30x / 10( 1-x ) = 1.3 / 1
30x = (10 - 10x)1.3
30x = 13 - 13x
30x + 13x = 13
x = 13/43
x = 0.3023
Also, ( 1-x ) = ( 1 - 0.3023) = 0.6977
so
C1/C2 = 0.3023/0.6977 = 1 / 2.308 while c3 can be anything;
Therefore, C1 : C2 : C3 = 1 : 2.308 : C3
What effect is climate change having on the amount of water in liquid, solid, and gas forms on Earth?
which would be a stronger acid H3PO4 or H3PO2
Answer:
h3po2
Explanation:
Answer:
i think it is H3PO4
Explanation:
In order to produce some SbCl5, a 1.00 mole sample of SbCl3 is first placed in an empty 2.00 liter container maintained at a temperature different from 182oC. At this temperature, Kc, equals 0.117. How many moles of Cl2 must be added to this container to reduce the number of moles of SbCl3 to 0.700 mole at equilibrium
x = = 0.50 M Answer:
In order to produce some SbCl5, a 1.00 mole sample of SbCl3 is first placed in an empty 2.00 liter container maintained at a temperature different from 182oC. At this temperature, Kc, equals 0.117. How many moles of Cl2 must be added to this container to reduce the number of moles of SbCl3 to 0.700 mole at equilibrium
Moles Cl2 that must be added = 0.40 mol
Explanation:
K = ( = 0.117
Equilibrium concentrations:
= (1.00 - 0.70) mol / 2.00 L = 0.15 M <<---why is it 1.00-0.70???
= 0.700 mole / 2.00L = 0.350 M
= x
Kc = ÷ (0.15) = 0.117
Moles Cl2 at equilibrium = 0.050 mol L x 2.00 L = 0.10 mol
Moles Cl2 needed to make 0.300 mol SbCl3 into SbCl5 = 0.30 mol
Moles Cl2 that must be added = 0.40 mol
Calculate the molarity (M) if 3.35g of H3PO4 is dissolved in water to give a total volume of 200mL
Answer:
0.171 M
Explanation:
Step 1: Given data
Mass of H₃PO₄ (solute): 3.35 gVolume of solution (V): 200 mLStep 2: Calculate the moles of solute
The molar mass of H₃PO₄ is 97.99 g/mol.
3.35 g × 1 mol/97.99 g = 0.0342 mol
Step 3: Convert "V" to liters
We will use the conversion factor 1 L = 1000 mL.
200 mL × 1 L/1000 mL = 0.200 L
Step 4: Calculate the molarity of the solution
We will use the definition of molarity.
M = moles of solute / liters of solution
M = 0.0342 mol/0.200 L = 0.171 M
The number of atoms in 10. grams of calcium is equal to 6.0 x 1023 multiplied by which number?
Answer:
1.51×10²³ atoms.
Explanation:
From the question given above, the following data were obtained:
Mass of Calcium (Ca = 10 g
Number of atom of Calcium (Ca) =?
The number of atoms present in 10 g of Ca be obtained as follow:
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ atoms. This implies that 1 mole Ca contains 6.02×10²³ atoms.
1 mole of Ca = 40 g.
Now, if 40 g of Ca contains 6.02×10²³ atoms.
Therefore, 10 g of Ca will contain = (10 × 6.02×10²³) / 40 = 1.51×10²³ atoms.
Thus, 10 g of calcium contains 1.51×10²³ atoms.
The concentration of lithium chlorite solution is 12.0% by mass. In a ___g sample of this solution, there are 238.5g of dissolved lithium chlorate.
Answer is A) 1990 but I do not know to go to there please help!
Mass of sample : 1987.5 g≈1990 g
Further explanationGiven
12% mass of Lithium chlorate
Required
Mass of sample
Solution
%mass = (mass of solute/mass of solution) x 100%
mass of solute = mass of Lithium chlorate = 238.5 g
Input the value :
12/100(0.12) = 238.5 g : mass of solution
mass of solution =238.5 : 0.12
mass of solution = 1987.5≈1990 g
Who has the more valued Exports?
South Africa or Egypt?
pls help ill mark brainliest! star and heart :)
Answer:
Egypt
Explanation:
Hi again
Balance the equation
Answer:2NaF + Br2 —> 2NaBr + F2
2K + Cl2 —> 2KCl
N2+ 3F2 —> 2NF3
Explanation: