Answer:
1000 kJ.mmole / 1000 J.mole
Explanation:
To solve this, we need to analyze the given data.
We have a number which is 87.1 J/mmole.C (I'm assuming it has the J at the beggining because if not, then you are missing some data) and the final result is kJ/mol.C
The only unit that has not changed in the process was the °C, while the mole and J change respectively. In this case, we need to know the conversion factor of mmole to mole and J to kJ.
In the case of a mole:
1 mole --------> 1000 mmole
In the case of Joule:
1 kJ ----------> 1000 J
So the first thing we will do is to change from J to kJ:
87.1 J * 1 kJ / 1000 J = 0.0871 kJ
Now let's convert mmol to mole:
0.0871 kJ/mmole.C * 1000 mmole / 1 mole = 87.1 kJ/mole.C
As you can see, there's is practicly no change at all with the units, so putting all together it would be:
87.1 J/mmole.C * 1000 kJ.mmole / 1000 J.mole = 87.1 kJ/mole.°CHope this helps
Halogenated compounds are particularly easy to identify by their mass spectra because chlorine and bromine occur naturally as mixtures of two abundant isotopes. Chlorine occurs as 35Cl (75.8%) and 37Cl (24.2%); Bromine occurs as 79Br (50.7%) and 81Br (49.3%); Boron compounds also stand out owing to the two isotopes 10B (19.9%) and 11B (80.1%).
Required:
a. At what masses do the molecular ions occur for the following formulas?
b. What are the relative percentages of each molecular ion?
Answer:
Explanation:
From the given information:
The compound in question here is [tex]\mathbf{C_2H_5Br}[/tex]
The molar mass of [tex]\mathbf{C_2H_5Br}[/tex] with 79 Br is;
= (2 × 12) + (1 × 5) + 79
= 108 g/mol
The molar mass of [tex]\mathbf{C_2H_5Br}[/tex] with 81 Br is:
= (2 × 12) + (1 × 5) + 81
= 110 g/mol
Thus, the mass at which the molecular ions occurs are:
108 and 110.
The relative percentage of mass 108 occurred at 50.7%
The relative percentage of mass 110 occurred at 49.3%
Dolphins have the same arm structure as wolves. What type of evidence for evolution does this represent?
A. DNA
B. vestigial structures
C.homologous structures
D. embryology
A 1.018 g sample pure platinum metal was reacted with HCl to form 1.778 g of a compound containing only platinum and chlorine. Determine the empirical formula of this "Pt-Cl" Compound.
Answer:
[tex]PtCl_4[/tex]
Explanation:
Hello!
In this case, since HCl and Pt react according to the following chemical equation:
[tex]HCl+Pt\rightarrow PtCl_x+H_2[/tex]
Whereas PtClx is the compound containing Pt and Cl; thus, since 1.018 g out of 1.778 g correspond to Pt and therefore 0.760 g to chlorine, so we determine the empirical formula of this compound by firstly computing the moles of each element:
[tex]n_{Pt}=1.018gPt*\frac{1molPt}{195.084gPt}=0.00522molPt\\\\\\n_{Cl}=0.760gCl*\frac{1molCl}{35.45gCl} =0.0214molCl[/tex]
Now, we divide the each moles by those of Pt as the fewest ones in order to compute their subscripts in the empirical formula:
[tex]Pt=\frac{0.00522}{0.00522}=1 \\\\Cl=\frac{0.0214}{0.00522} =4[/tex]
Thus, the required formula is:
[tex]PtCl_4[/tex]
Best regards!
In the Energy and Specific Heat lab, what temperature should be recorded as the final temperature of the water when measuring the food sample?
A. The temperature of the water when the food sample is first lit
B. The temperature of the water when the food sample has finished burning completely.
C. The highest temperature the water reaches as the sample burns
D. The temperature of the water after the food sample ash has been removed
Answer:
B. The temperature of the water when the food sample has finished burning completely.
Explanation:
Heat or thermal energy is a form of energy that transfers from one object to another due to a temperature difference between the objects. The units for heat are joules or calories.
Calorimetry is the measurement of heat energy released or absorbed in a chemical reaction. A calorimeter is used in calorimetry. The calorimeter operates on the Law of Conservation of Energy which states that energy is never created or destroyed but is transformed from one form to another or between objects.
In food calorimetry, the energy released when food is burned is measured by recording the rise in temperature of water in a calorimeter when a given mass of a food sample is burned completely.
Energy can be calculated using the formula: Q = mc ∆T
where Q = the energy in joules or calories, m = the mass in grams, c = specific heat and ∆T = the change in temperature (final temperature - initial temperature).
The temperature of the water when the food sample has finished burning completely is taken as the final temperature of the water. The sample is allowed to smolder for sometime before recording the final water temperature. This is because the water temperature will continue to rise after the flame has gone out.
The 10x SDS gel electrophoresis buffer contains 250mM Tris HCl, 1.92M Glycine, and 1% (w/v) SDS. Buffers are always used at 1x concentration in the lab (unless specified otherwise in the protocol), so you will have to dilute the 10x buffer to 1x before use. What is the concentration of Tris and SDS in the 1x buffer
Answer:
25 mM Tris HCl and 0.1% w/v SDS
Explanation:
A 10X solution is ten times more concentrated than a 1X solution. The stock solution is generally more concentrated (10X) and for its use, a dilution is required. Thus, to prepare a buffer 1X from a 10X buffer, you have to perform a dilution in a factor of 10 (1 volume of 10X solution is taken and mixed with 9 volumes of water). In consequence, all the concentrations of the components are diluted 10 times. To calculate the final concentration of each component in the 1X solution, we simply divide the concentration into 10:
(250 mM Tris HCl)/10 = 25 mM Tris HCl
(1.92 M glycine)/10 = 0.192 M glycine
(1% w/v SDS)/10 = 0.1% w/v SDS
Therefore the final concentrations of Tris and SDS are 25 mM and 0.1% w/v, respectively.
ANSWER QUICK !!!
How many grams of hydrogen gas will be produced if you start with 15.0 grams of zinc and an excess amount of HCI?
balanced equation:
Zn + 2HCI = ZnCl2 + H2
Answer:
0.48g
Explanation:
Given parameters:
Mass of zinc = 15g
Unknown:
Mass of hydrogen gas = ?
Solution:
To solve this problem, we need to state the balanced reaction expression first;
Zn + 2HCl → ZnCl₂ + H₂
Find the number of moles of Zn;
Number of moles = [tex]\frac{mass}{molar mass}[/tex] = [tex]\frac{15}{63.4}[/tex] = 0.24mol
From the balanced reaction expression;
1 mole of Zn will produce 1 mole of H₂
0.24mole of Zn will produce 0.24mole of hydrogen gas
Mass of hydrogen gas = number of moles x molar mass
= 0.24 x (2 x 1)
= 0.48g
7. Use the concepts of relative abundance and relative weight to explain why carbon has an atomic mass of 12.011 amu when there are three isotopes of carbon weighing 12 amu, 13 amu and 14 amu. Why is the atomic mass not 13?
The uncertainties of the delta measurements and the uncertainty of the atomic weight derivedfrom the best measurement of isotopic abundances constrain the number of significant figures in theatomic-weight values of the upper and lower bounds. For carbon, the fifth digit after the decimal pointis uncertain because of the uncertainty value of 0.000 027. Therefore, the number of significant digitsin the atomic-weight value is reduced to four figures after the decimal point. The Commission may rec-ommend additional conservatism and reduce the number of significant figures further. For the lowerbound of carbon, 12.009 635 is truncated to 12.0096. For an upper bound, the trailing digit is increasedto ensure the atomic-weight interval encompasses the atomic-weight values of all normal materials. Inthe case of carbon, the upper bound is adjusted from 12.011 532 to 12.0116 to express four digits afterthe decimal point. The lower and upper bounds are evaluated so that the number of significant digits ineach is identical. If a value ends with a zero, it may need to be included in the value to express therequired number of digits. The following are examples of lower and upper atomic-weight bounds foroxygen that could be published by the Commission in its various tables.
---------------------------
Extracted from" Atomic weights of the elements 2009 (IUPAC Technical Report)"
Which statement correctly describes ionic bonds? Multiple Choice An ionic bond only forms between two atoms of the same element. Ionic bonds usually form between electrically neutral, stable atoms. An ionic bond is the electrostatic force that holds ions together when they form bonds. All of the answer choices are correct.
Answer:
An ionic bond is the electrostatic force that holds ions together when they form bonds
Explanation:
An ionic bond is formed when a metal looses electron(s) to a non metal leading to the formation of a positive ion and a negative ion.
An ionic compound is actually an ion pair, the ions are held together by strong electrostatic forces.
This strong electrostatic force that holds the ion pair together in ionic compounds is what we commonly call the IONIC BOND.
Answer:
An ionic bond is the electrostatic force that holds ions together when they form bonds
Explanation:
I took this test and it was the correct answer :)
What are suspensions
Answer: suspensions are a mixture in which solute particles do not disolve. An example is oil and water, oil and water or even flour and water; oil can’t disolve in water
Answer:
Noun: a mixture in which particles are dispersed throughout the bulk of a fluid.
Adjective: the state of being dispersed in a fluid.
Explanation:
I used a dictionary lol
Photosynthesizing organisms use ____
to produce glucose.
Answer: Photosynthesizing organisms use carbon dioxide and water to produce glucose.
Explanation:
Photosynthesis is a phenomenon in which green plants containing chlorophyll use sunlight as a source of energy to convert carbon dioxide and water to form glucose and oxygen.
Photosynthesis is the process used by plants, algae and certain bacteria to convert energy from sunlight and turn it into chemical energy in the form of glucose which is used a s a source of energy by many organisms.
[tex]6CO_2+6H_2O\overset{sunlight}\rightarrow C_6H_{12}O_6+6O_2[/tex]
which type of bond involves 2 different metals?
A. ionic
B. Covalent
C.Metallic
D. Bonding would not occur
Answer:
iconic bond is the answer
I hope it helps you ✌
Based on the following chemical equation how many hydrogen atoms are present in the products side?
N2 + 3H2 ----> 2NH3
Question 2 options:
5
3
6
1
The number of Hydrogen atoms = 6 atoms
Further explanationGiven
Reaction
N₂ + 3H₂ ⇒ 2NH₃
Required
The number of Hydrogen atoms
Solution
The reaction coefficient of a chemical equation shows the mole ratio of the reacting compound.
On a compound the reaction coefficient indicates the number of molecules
Whereas the subscript after the atom shows the number of atoms in that compound
Product from the reaction : 2NH₃
Number of H-atoms :
= 2 x 3
= 6 atoms
A 1.018 g sample pure platinum metal was reacted with HCl to form 1.778 g of a compound containing only platinum and chlorine. What is the percent by mass of platinum?
Answer:
57.26 %
Explanation:
Step 1: Write the balanced equation
Pt + 2 HCl ⇒ PtCl₂ + H₂
Step 2: Calculate the mass of Pt in 1.778 g of PtCl₂
According to the law of conservation of the mass, all the mass of Pt in the reactants must be present in the products. Since PtCl₂ is the only product that contains Pt, the mass of Pt is 1.018 g
Step 3: Calculate the percent by mass of platinum in PtCl₂
We will use the following expression.
%Pt = mPt / mPtCl₂ × 100%
%Pt = 1.018 g / 1.778 g × 100% = 57.26 %
How do plate tectonics affect mountains?
Mountains outline plate tectonic boundaries.
Plate tectonics spreading can create mountains.
Plate tectonic collisions can create mountains.
Mountains provide evidence for plate tectonics.
Answer:
C. Plate tectonic collisions can create mountains.
Answer:
They can make them larger
Explanation:
They go up under a mountain and then the mountains rise up
What is the difference between the grassland and savanna biomes?
A)Grassland biomes are closer to the equator and receive more rain.
B)Savanna biomes are closer to the equator and receive more rain.
C)Grassland biomes contain mostly grasses.
D)Savanna biomes contain mostly grasses.
Answer:
C)Grassland biomes contain mostly grasses.
Explanation:
The main differences between a savanna biome and a grassland is that grasslands biomes contain mostly grasses.
Savanna are made up of both grasses and shrubs.
Savanna are a mix of grasslands with some scattered trees in the area. Grasslands are open grass fields. They do not contain much trees as such. The savanna and grasslands are renowned for their fauna diversity of beasts.I need help with answer 1 and 2 ASAP please!!
Answer:
1. B 2.B
Explanation:
Which of the following is the poorest conductor of electricity?
Calcium (Ca)
Silicon (Si)
Fluorine (F)
Sodium (Na)
Cobalt (Co)
Answer:
Fluorine (F)
Explanation:
The poorest conductor of electricity from the given choices is fluorine. This is because fluorine is a non - metal.
Like other non - metals, fluorine does not conduct electricity.
Only metals are known to conduct electricity and heat readily.
Semi - metals like silicon will conduct electricity under specific condition.
The free mobile electrons in metals makes it easy for them propagate electricity
a titanium bicycle frame displays 0.250 L of water and has a mass of 1.21kg. what is the density of the titanium on g/cm3?
Answer:
$4.49 g/cm3
Explanation:
Density=Mass/Volume
plzz put brainiest
A geochemist in the field takes a 36.0 mL sample of water from a rock pool lined with crystals of a certain mineral compound X. He notes the temperature of the pool, 170 C, and caps the sample carefully. Back in the lab, the geochemist filters the sample and then evaporates all the water under vacuum. Crystals of are left behind. The researcher washes, dries and weighs the crystals. They weigh 3.96 g. Using only the information above, can you calculate the solubility of X in water at 17.0C? If you said yes, calculate it.
Answer:
Yes, 0.11g/mL is the solubility of X in water at 17.0°C.
Explanation:
As the sample of water has crystals around it, the solution is oversaturated at 17.0°C. The water contains the maximum amount of X at 17.0°C, this concentration is called solubility. Thus, yes, we can calculate solubility in water at 17.0°C
The concentration of the crystals is 3.96g in 36.0mL, that is:
3.96g / 36.0mL =
0.11g/mL is the solubility of X in water at 17.0°CIdentify the missing species in each nuclear equation. Replace the question marks with the appropriate integer or symbol. Be410⟶B510+Be410⟶B510+ β−10β−10 Si1434⟶P1534+Si1434⟶P1534+ Pt78192⟶Pt78192⟶ pp?+ 42????+ 24α pp?⟶Al1328+β−10
Answer:
1. ¹⁰₄Be ---> ¹⁰₅B + ⁰₋₁β
2. ³⁴₁₄Be ---> ³⁴₁₅P + ⁰₋₁β
3. ¹⁹²₇₈Pt -----> ¹⁹⁰₇₆Os + ⁴₂α
4. ²⁸₁₂Mg ---> ²⁸₁₃Al + ⁰₋₁β
Explanation:
1. In the first equation, Beryllium-10 isotope undergoes beta-decay, emitting a beta-particle to form boron-10 isotope. The balanced nuclear equation is given below:
¹⁰₄Be ---> ¹⁰₅B + ⁰₋₁β
2. In this reaction, silicon-34 isotope undergoes beta-decay, emitting a beta-particle to form phosphorus-34 isotope. The balanced nuclear equation is given below:
³⁴₁₄Be ---> ³⁴₁₅P + ⁰₋₁β
3. In this equation, platinum-192 isotope undergoes alpha-particle decay emitting an alpha-particle to form osmium-190 isotope. The balanced nuclear equation is given below:
¹⁹²₇₈Pt -----> ¹⁹⁰₇₆Os + ⁴₂α
4. In this equation, magnesium-28 isotope undergoes beta-decay, emitting a beta-particle to form aluminum-28 isotope. The balanced nuclear equation is given below:
²⁸₁₂Mg ---> ²⁸₁₃Al + ⁰₋₁β
A sample of saturated clay was placed in a container and weighed. The weight was 6N. The clay in its container was placed in an oven for 24 hours at 105° C. The weight reduced to a constant value of 5N. The weight of the container is 1N. If G-2.7, determine the:
(a) water content;
(b) void ratio;
(c) bulk unit weight;
(d) dry unit weight;
(e) effective unit weight.
Answer is given below
Explanation:
given data
weight = 6N
temp = 105° C
weight reduced = 5N
solution
weight of container is 1N
SO W = (6-1) = 5
And Wd = 5 - 1 = 4
so
moisture content is
moisture content = [tex]\frac{W-Wd}{Wd} \times 100[/tex] .......1
moisture content = [tex]\frac{5-4}{4} \times 100[/tex]
moisture content = 25%
and
as we know density of soil soild = 2700 kg/m³
density of water = 1000 kg/m³
and sp gravity of soil = [tex]\frac{2700}{1000}[/tex] = 2.7
so
now we get here bulk unit weight
bulk unit wt = [tex]Yw \times [\frac{G+e}{1+e}][/tex] ..........2
bulk unit wt = [tex]9.01 \times [\frac{2.7 + 0.675}{1+0.675}][/tex]
bulk unit wt = 19.766 KN/m³
and
so dry unit wt will be
dry unit wt = [tex]\frac{Ysat}{1+w}[/tex] ..............3
dry unit wt = [tex]\frac{19.766}{1+0.25}[/tex]
dry unit wt = 15.813 kN/m³
Enter your answer in the provided box. Muriatic acid, an industrial grade of concentrated HCl, is used to clean masonry and cement. Its concentration is 11.7 M. For routine use, a diluted solution of 3.50 M is prepared. How many milliliters of 3.50 M muriatic acid solution contain 32.8 g of HCl
Answer:
257 mL
Explanation:
Step 1: Given data
Concentration of the muriatic acid solution used (C): 3.50 M (3.50 mol/L)Mass of HCl (m): 32.8 gStep 2: Calculate the moles (n) corresponding to 32.8 g of HCl
The molar mass of HCl is 36.46 g/mol.
32.8 g × 1 mol/36.46 g = 0.900 mol
Step 3: Calculate the volume (V) of solution required
We will use the following expression.
C = n/V
V = n/C
V = 0.900 mol/(3.50 mol/L)
V = 0.257 L = 257 mL
Please help me on this
How many moles of Fe2O3 are in 17.2g?
A - 1.23
B - 2.75
C - 0.239
D - 0.108
Answer:
C
Explanation:
0.10 moles of Fe[tex]_2[/tex]O[tex]_3[/tex] are in 17.2g. Therefore, the correct option is option D among all the given options.
What is iron(III) oxide?The inorganic chemical with both the formula Fe[tex]_2[/tex]O[tex]_3[/tex] is iron(III) oxide and ferric oxide. It is one of three major iron oxides, the other 2 including iron(II) oxide (FeO), which would be uncommon, and iron(II,III) oxides (Fe[tex]_2[/tex]O[tex]_3[/tex]), which naturally occurs as the mineral magnetite.
Acids have a high affinity for Fe[tex]_2[/tex]O[tex]_3[/tex] . Iron(III) oxide is commonly referred to as rust, and this name is appropriate to some extent because rust has certain features and has a comparable composition; nevertheless, in chemistry, colouration is classified under Hydrous ferric oxide.
mole = 17.2/ 159.69 =0.10moles
Therefore, the correct option is option D.
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What volume, in liters, would 88.9 grams of a substance occupy if it’s density is 2.38 g/mL
Answer:
V = 0.03735 mL
Explanation:
Given that,
Mass of a substance, m = 88.9 grams
Density of a substance, d = 2.38 g/mL
We need to find the volume occupied by the object. The density of an object is given by mass per unit volume.
[tex]d=\dfrac{m}{V}\\\\V=\dfrac{m}{d}\\\\V=\dfrac{88.9}{2.38}\\\\V=37.35\ mL\\\\V=0.03735\ L[/tex]
So, the volume of the substance is 0.03735 mL.
What role do wolves play in the tundra?
Answer:
predator
Explanation:
Wolves, arctic foxes, and snowy owls are predators in the tundra.
Drag the tiles to the correct boxes to complete the pairs.
Match the descriptions with the types of blas.
selection bias
expectation bias
confirmation bias
contextual bias
paying more attention to evidence that
confirms one's hypothesis and ignoring
evidence that may discount it
to be swayed from one's conclusion by
additional information
coming to a conclusion before all the
evidence has been processed and therefore
unconsciously disregarding evidence to the
contrary
Answer:
Explanation:
here's the answer hope it helps! :)
If you rewite the following word equation as a balanced chemical equation, what will the coefficient and symbol for iodine be?
bromine + potassium iodide → potassium bromide + iodine
A 2I
B I
C 2I
D I2
E 2I2
The coefficient and symbol for iodine be I₂.
What is the coefficient in a chemical equation?Coefficients are the numbers used to balance chemical equations and are placed in front of a chemical symbol or formula. It tells us about how many atoms or molecules of substance or compound are involved in the reaction.As in mathematics, coefficient is the number used in front of a variable similarly in chemistry, coefficient is a number used in chemical equation, just as a prefix of chemical formula to define the number of molecules reacting and producing in a reaction. We add coefficients to balance the chemical equations so as to assure that law of conservation of mass is being followed.bromine + potassium iodide → potassium bromide + iodine
The balanced chemical equations:
Br₂ + 2KI → 2KBr + I₂
2KBr means 2 molecules of potassium iodide.
From the above balanced equation, we know that the coefficient of bromine = 2, iodine = 2, potassium iodide = 2and potassium bromide = 2.
Hence, option D is the correct answer.
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Last week at a tax free sale, Ms. Kuhn bought 4 shirts for $15.95 each and 2 new belts
that cost $8.95 each. If she paid with a $100 bill, how much change did she receive?
$18.30
$75.10
$2490
$24.90
Answer:
$18.30
Explanation:
The change is the amount left over after the selling price has been matched by the buyer.
Let us find the total cost of what of Ms. Kuhn bought;
For the shirt;
Cost = 4 shirts for $15.95 each = 4(15.95) = $63.8
2 new belts for $8.95 each = 2(8.95) = $17.9
Total cost = $63.8 + $17.9 = $81.7
The amount of change left = $100 - $81.7 = $18.3
Calculate the mass of butane needed to produce 99.0 g of carbon dioxide.
Express your answer to three significant figures and include the appropriate units.
Answer:
32.7 g
Explanation:
Step 1: Write the balanced combustion reaction
C₄H₁₀ + 6.5 O₂ ⇒ 4 CO₂ + 5 H₂O
Step 2: Calculate the moles corresponding to 99.0 g of CO₂
The molar mass of CO₂ is 44.01 g/mol.
99.0 g × 1 mol/44.01 g = 2.25 mol
Step 3: Calculate the moles of C₄H₁₀ needed to produce 2.25 moles of CO₂
The molar ratio of C₄H₁₀ to CO₂ is 1:4. The moles of C₄H₁₀ needed are 1/4 × 2.25 mol = 0.563 mol.
Step 4: Calculate the mass corresponding to 0.563 moles of C₄H₁₀
The molar mass of C₄H₁₀ is 58.12 g/mol.
0.563 mol × 58.12 g/mol = 32.7 g