If the heat of fusion for water is 334 j/g, how many Jules are needed to melt 45.0 g of ice at 0.0°c?
Given parameters:
Heat of fusion of water = 334j/g
Mass of ice = 45g
Temperature of ice = 0.0°c
Unknown:
Amount of heat needed to melt = ?
Solution:
This is simply a phase change and a latent heat is required in this process.
To solve this problem; use the mathematical expression below;
H = mL
where m is the mass
L is the heat of fusion of water;
H = 45 x 334 = 15030J
Question 2
1 pts
Which compound would you predict to be most soluble in water and why: NH,Br or NHACI?
Assume Br is larger than CI.
O NH Br because the distance between the lons is shorter
O NH Br because the distance between the lons is longer
These are equally soluble because their lons have the same charge
O NH CI because the distance between the lons is longer
O NHACI because the distance between the lons is shorter
1.8 x 1022 atoms of Rn to moles of Rn
Answer:
1.8×10²² atom of Rn contain 0.03 moles of Rn.
Explanation:
Given data:
Number of atoms of Rn = 1.8×10²² atoms
Number of moles = ?
Solution:
we will solve this problem through Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.
For example,
1 mole of Rn = 6.022 × 10²³ atoms of Rn
1.8×10²² atoms of Rn × 1mol / 6.022 × 10²³ atoms of Rn
0.3×10⁻¹ moles of Rn
0.03 moles of Rn
1. 500 grams of sugar occupies a volume of 315 ml. What is the density of the sugar in g/mL? Show
your work.
Answer:
The answer is 1.59 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\[/tex]
From the question
mass = 500 g
volume = 315 mL
We have
[tex]density = \frac{500}{315} = \frac{100}{63} \\ = 1.587301...[/tex]
We have the final answer as
1.59 g/mLHope this helps you
Here is a more complex redox reaction involving the permanganate ion in acidic solution
In the redox reaction involving the permanganate ion in acidic solution, permanganate ion is reduced to manganese (ii) ion while iron (ii) ion is oxidized to iron(iii) ion.
What is a redox reaction?A redox reaction is a reaction in which reduction and oxidation occurs at the same time and to the same extent.
An example of a redox reaction is the reaction involving the permanganate ion and tetraoxosulphate (vi) ion in acidic solution.
The equation of the reaction is given below:
[tex]MnO_{4}^{ - } (aq) + 5Fe^{2+}(aq) + 8H^{+} \rightarrow Mn^{2+}(aq)+ 5Fe^{3+}(aq) +4H_{2}O(l) \\ [/tex]
Therefore, in the redox reaction involving the permanganate ion in acidic solution, permanganate ion is reduced to manganese (ii) ion while iron (ii) ion is oxidized to iron(iii) ion.
Learn more about redox reaction at: https://brainly.com/question/26750732
#SPJ1
A chemist dissolves 320.mg of pure nitric acid in enough water to make up 290.mL of solution. Calculate the pH of the solution. Be sure your answer has the correct number of significant digits.
Answer:
1.7
Explanation:
The formula to be used here is;
pH = -log[H⁺]
To determine the concentration of H⁺ of the nitric acid (HNO₃), formula for molarity is used
Molarity = number of moles/volume (in dm³ or L)
number of moles (n) = given mass/molar mass
Molar mass of HNO₃ = 1 + 14 + (16 x 3)
= 63g
given mass (in grams) = 320mg⇔0.32g (where 1000mg = 1g)
Thus; n = 0.32/63
n = 0.0051 moles
Volume of acid = 290 mL ⇔ 0.29 L (where 1000 mL = 1L)
Molarity = n/volume;
0.0051/0.29
Molarity = 0.018M
pH = -log 0.018
pH = 1.7
What are two ways nitrogen fixation occurs
Explanation:
natural process
biological fixation
The density of aluminum is 2.7 g/cm3. A metal sample has a mass of 52.0 grams and a volume of 17.1 cubic centimeters. Could the sample be aluminum? EXPLAIN your answer.
Answer:
The given metal sample is not aluminum because its density is 3.0 g/cm³ while density of aluminum is 2.7 g/cm³.
Explanation:
Given data:
Density of aluminum = 2.7 g/cm³
Mass of metal sample = 52.0 g
Volume of metal sample = 17.1 cm³
which sample is that = ?
Solution:
The given problem will be solve through density formula.
d = m/v
d = density
m = mass
v= volume
Now we will put the values in formula.
d = 52.0 g/ 17.1 cm³
d = 3.0 g/cm³
It is given in question the density of aluminum is 2.7 g/cm³. The given metal sample is not aluminum because its density is 3.0 g/cm³.
The closeness of particles of gas and their low speeds allow intermolecular forces to become important at certain
pressures and temperatures. Which best describes this statement?
Answer:
This is a limitation of the kinetic-molecular theory.
Explanation:
Two compounds of phosphorus and flurorine have the following mass ratios
Compound 1: 10.14 g fluorine for every 3.38 g phosphorus
Compound 2: 8.42 g flurorine for every 4.21 g phosphorus
Find the whole number ratio of masses of flurorine in compound 1 to compound 2
Answer:
25.6 Explanation:
are
Why the elements of d-block elements
called transition element?
Answer:
O nome "transição" vem da posição dos elementos na tabela, representando a transição do grupo 2 ao 13, pela sucessiva adição de elétrons ao orbital d. Elementos de transição externa (ou somente elementos de transição):
What functional group is present in the following compound?
3) A certain reaction has the following general form: A + B à AB At a particular temperature the concentration versus time were collected for this reaction, and a plot of ln[A]t versus time resulted in a straight line with a slope of −3.7 x 10−3 s−1. Show your math! (5 points) a. What is the order of the reaction? b. What is the rate constant (including units)? c. Calculate the half-life for the reaction. d. If the initial concentration of A is 0.250 M, what is the concentration after 220 seconds?
Answer:
a. First order.
b. [tex]k=3.7x10^{-3}s ^{-1}[/tex]
c. [tex]t_{1/2}=187.3s[/tex]
d. [tex][A]=0.111M[/tex]
Explanation:
Hello.
a. In this case since the slope is in s⁻¹ we can infer that the lineal form of the rate law is:
[tex]ln[A]=-kt+ln[A]_0[/tex]
Which is also:
[tex]y=mx+b[/tex]
It means that the reaction is first-order as slope equals the negative of the rate constant which also has units of first-oder reaction.
b. Since the slope is −3.7 x 10−3 s−1 the rate constant is:
[tex]k=-m\\\\k=-(-3.7x10^{-3}s ^{-1})\\\\k=3.7x10^{-3}s ^{-1}[/tex]
c. For first-order reactions, the half-life is:
[tex]t_{1/2}=\frac{ln(2)}{k}\\ \\t_{1/2}=\frac{ln(2)}{3.7x10^{-3}s^{-1}}\\\\t_{1/2}=187.3s[/tex]
d. In this case, since the integrated first-order rate law is:
[tex][A]=[A]_0exp(-kt)[/tex]
The concentration once 220 seconds have passed is:
[tex][A]=0.250Mexp(-3.7x10^{-3}s^{-1}*220s)\\\\[/tex]
[tex][A]=0.111M[/tex]
Regards.
do people cause melting glaciers
Answer:
Human activities are at the root of this phenomenon.
Explanation:
Whose measurements are more precise?20.3 cm and 21.0cm
Answer:
will i think the 21.0cm
Do you agree in the Big Bang theory? Reasoning
Was the periodic table of elements created at once by one scientist yes or no
Answer:
Yes
Explanation:
It was Dmitri Mendeleev, a Russian chemist and teacher.
Answer:
No, it wasn't. On Feb.17 in 1869, a very intelligent Russian professor of chemistry, Dimitri Ivanovich Mendeleev created his first part of the periodic table. I hope that helps you.
Explanation:
) If 1 vitamin C tablet weighs 475 mg how much vitamin C is in that 1 tablet based on your
calculations?
Answer:
Amount = 0.0027 mol
Explanation:
The molecular formula of vitamin C is: C₆H₈O₆. Therefore, its molar mass will be:
Molar Mass = 6(Mass of carbon) + 8(Mass of Hydrogen) + 6 (Mass of Oxygen)
Molar Mass = 6(12 g/mol) + 8(1 g/mol) + 6(16 g/mol)
Molar Mass = 176 g/mol
Molar Mass = 176000 mg/mol
Now, for the amount of Vitamin C in 1 tablet
Amount = Mass of Tablet/Molar Mass
Amount = (475 mg)/(176000 mg/mol)
Amount = 0.0027 mol
An object has a mass of 35.00 grams. On Luixandras balance it weighs 33.95 grams. What is the percent error in this balance?
Answer:
The answer is 3 %Explanation:
The percentage error of a certain measurement can be found by using the formula
[tex]P(\%) = \frac{error}{actual \: \: number} \times 100\% \\ [/tex]
From the question
actual mass = 35 g
error = 35 - 33.95 = 1.05
We have
[tex]p(\%) = \frac{1.05}{35} \times 100 \\ [/tex]
We have the final answer as
3 %Hope this helps you
liqued in which a substance dissolve
Answer: Water as its the universal solvent
Which of the following is the correct formula used for calculating Speed?
Speed = distance / time
Speed = time / distance
Speed = mass / time
Answer:
A- Speed = distance/time
Explanation:
Would make sense and that's what I remember
marshmallow is costly, what type of food is marshmallow?
a.suspension b.solution c.colloid
Answer:
b solution
Explanation:
Define energy transformation.
Answer:
Enery transformation is when a forn of energy changes into another.
Explanation:
An example of this would be a lamp. The lamp gets its energy through electricity. This electricity is later turned into light energy. Electrical energy to light evegy.
the valency of nitrogen is 3 why
Answer:
The nitrogen atom has 5 electrons in the outermost shell, so it can accept 3 electrons to fulfil the octet structure. Therefore the valency of nitrogen is 3.
Be sure to answer all parts. Consider the reaction 2SO2(g) + O2(g) ⇌ 2SO3(g)ΔH = −198.2 kJ/mol How would the concentrations of SO2, O2, and SO3 at equilibrium change if we were to (a) increase the temperature? [SO2]: The concentration increases. The concentration decreases. There is no change. [O2]: The concentration increases. The concentration decreases. There is no change. [SO3]: The concentration increases. The concentration decreases. There is no change. (b) increase the pressure and decrease the volume? [SO2]: The concentration increases. The concentration decreases. There is no change. [O2]: The concentration increases. The concentration decreases. There is no change. [SO3]: The concentration increases. The concentration decreases. There is no change. (c) add a catalyst? [SO2]: The concentration increases. The concentration decreases. There is no change. [O2]: The concentration increases. The concentration decreases. There is no change. [SO3]: The concentration increases. The concentration decreases. There is no change.
Answer:
a)
[SO2]: The concentration increases
[O2]: The concentration increases.
[SO3]: The concentration decreases.
b)
[SO2]: The concentration decreases.
[O2]: The concentration decreases.
[SO3]: The concentration increases.
c)
[SO2]:There is no change.
[O2]: There is no change.
[SO3]: There is no change
Explanation:
For an exothermic reaction, increase in temperature decreases the concentration of products and increases the concentration of reactants since increase in temperature shifts the equilibrium position to the left hand side.
Increase in pressure and decrease in volume will shift the equilibrium position towards the right hand side which means more SO3 in the system.
Catalyst increases the rate of forward and reverse reaction simultaneously hence at equilibrium, the concentration of reactants and products remain unchanged.
what makes an element reactive
Answer:
The number of electrons in the outermost shell of an atom determines its reactivity.
Explanation:
Answer:
The number of electrons in the outermost shell of an atom determines its reactivity. Noble gases have low reactivity because they have full electron shells. Halogens are highly reactive because they readily gain an electron to fill their outermost shell.
Explanation:
Calculate the density of the following material: 500 kg gold with a volume of 0.026 m³.
Answer:
The answer is 19230.8 kg/m³Explanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\[/tex]
From the question
mass = 500 kg
volume = 0.026 m³
We have
[tex]density = \frac{500}{0.026} \\ = 19230.769230...[/tex]
We have the final answer as
19230.8 kg/m³Hope this helps you
What makes metals, in particular, good conductors of electricity?
A.
the ability of electrons to flow throughout the metal
OB.
the absence of charged particles
O c.
the high temperatures required to break metallic bonds
D.
the presence of positive and negative ions
Answer: I believe the answer is A
Which graph shows acceleration?
Graph A and B both show acceleration.
Graph B shows acceleration, but Graph A does not.
Neither graph shows acceleration. They both show velocity.
Graph A shows acceleration, but Graph B does not.
Answer:
graph a shows acceleration and b does not
Explanation:
the velocity increases in graph a, but stays constant in graph b
Answer:
graph a shows acceleration and b does not
Explanation:
A beaker contains 42.0 mL of carbon tetrachloride ( CCl4 , density is 1.59 g/mL). Determine how many molecules of carbon tetrachloride are in the beaker.
Answer:
Number of molecules = 2.61 x 10²³
Explanation:
Given:
Volume of tetra-chloride = 42 ml
Density = 1.59 g/ml
Find:
Number of molecules
Computation:
Mass = Volume of tetra-chloride x Density
Mass = 42 x 1.59
Mass = 66.78
Molecular mass of tetra-chloride = 154 g/mol
Moles = 66.78 / 154
Moles = 0.4337
0.4337 mole = 0.4337 x Avogadro number
0.4337 mole = 0.4337 x 6.022 x 10²³
Number of molecules = 2.61 x 10²³
