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
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
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 functional group is present in the following compound?
liqued in which a substance dissolve
Answer: Water as its the universal solvent
) 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
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
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):
Material
Appearance of the material,
including its color and state
baking soda
baking powder
Salt
sugar
flour
vinegar
cooking oil
The appearance and physical states of the material given is described below please look at it.
Appearance of the materials:Baking soda: It is a white solid.
Salt: it is white in color having a solid physical state.
Sugar: It is white in color having crystals or solid in physical state.
Flour: It is creamish white in color having solid particles.
Vinegar: It is transparent in color.
Cooking oil: It is a yellowish emulsion.
Find more information about Solid state here:
brainly.com/question/13503697
Group the elements into pairs that would most likely exhibit similar chemical properties. It does not matter which pair of elements is pair 1, pair 2, or pair 3, so long as the correct elements are paired. elements are N, As, Br, Mg, Sr, F
The elements in a group containing similar physical properties are
Pair 1 -- K and Li
Pair 2 -- S and Te
Pair 3 -- Br and F
Those elements which belong to the same group in the periodic table have similar number of valence electrons in the last shell and such elements exhibit similar properties.Potassium(K) and Lithium(Li) belong to a similar group i.e group 1.Sulfur (S) and Tellurium (Te) belong to a similar group i.e. group 16.Bromine(Br) and Flourine (F) belong to a similar group i.e. group 17Elements in a group exhibit similar periodic properties be it physical or chemical.It is in accordance with the periodic rules.To learn more periodic properties visit:
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#SPJ1
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:
Which property is not a physical property?
A. Color
B. Ability to Burn
C. Density
D. Melting Point
Answer: Ability to Burn
Explanation: I TOOK THE TEST
A sample of the igneous intrusion within the outcrop has 1682 Potassium-40 atoms, and 318 Argon-40 atoms. How old is the igneous intrusion
Answer: the igneous intrusion is 325 million years old
Explanation:
In the sample of the igneous intrusion
Number of Potassium-40 atoms (parent atom) = 1682
Number of Argon-40 atoms (daughter atom) = 318
Half-life of the Potassium40- Argon40 radioactive pair = 1.3 billion years = 1.3 × 10⁹ years
We now want to know the absolute age of the igneous intrusion.
At t = 0
i.e. when the igneous intrusion took place there will be no daughter atom (Ar-40).
So the number of parent (K-40) will be 1682 + 318 = 2000 atoms
Total number of atoms = parent + daughter = 2000 + 0 = 2000
Now after a given time
Number of Parent atom (K-40) = 1682
Number of Daughter atom (Ar-40) = 318
percent of parent atom (K-40)
= (Number of parent atom / total number of atoms) × 100
= (1682/2000) × 100
= 84.1 %
percentage of daughter atom (Ar-40) = 100 - % of K-40 atoms
= 100 – 84.1
= 15.9 %
Now from the table of “decay parameters for all radioactive decay pairs” which is uploaded along this answer
When Parent atom = 84.1 % and daughter atom = 15.9 %
then Age is given as 0.250T_1/2
THEREFORE age of the igneous intrusion
= 0.250 × 1.3 × 10⁹ years
= 0.325 × 10⁹ years
= 325 million years.
SO the igneous intrusion is 325 million years old
Compound X has the formula C8H12. X reacts with two molar equivalents of hydrogen in the presence of a palladium catalyst to form cyclooctane. Treatment of X with ozone followed by zinc in aqueous acid gives two molar equivalents of the same dialdehyde. What is the structure of X
Answer:
See explanation and image attached
Explanation:
If we look at the question closely, we will discover that two molar equivalents of hydrogen gas was used to obtain cyclooctane rom X. This implies that the compound X is an alkyne and it must be cyclooctyne since the hydrogen serves to reduce the triple bond and yield the corresponding alkane.
This is confirmed by the second statement which is ozonolysis of the X with zinc in aqueous acid which gave two molar equivalents of the same dialdehyde.
Image credit: Chem spider
2. What is an example of an object that affects gravity on Earth?
Answer:
The moon
Explanation:
The moon pulls on the earth, causing the tides to raise as the water is being pulled by the moon.
Whose measurements are more precise?20.3 cm and 21.0cm
Answer:
will i think the 21.0cm
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:
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.
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
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
Many plants are poisonous because their stems and leaves contain oxalic acid, H2C2O4, or sodium oxalate, Na2C2O4. When ingested, these substances cause swelling of the respiratory tract and suffocation. A standard analysis for determining the amount of oxalate ion, C2O 2− 4 , in a sample is to precipitate this species as calcium oxalate, which is insoluble in water. Write the net ionic equation for the reaction between sodium oxalate and calcium chloride, CaCl2, in aqueous solution.
Answer:
Explanation:
Calcium chloride is a soluble salt which dissociates into calcium and chloride ions when dissolved in water.
CaCl₂(aq) ----> Ca²⁺(aq) + 2Cl⁻(aq)
Similarly, sodium oxalate when dissolved in water dissociates into sodium and oxalate ions.
Na₂CO₄(aq) ----> 2Na⁺(aq) + C₂O₄²⁻(aq)
However, in a double displacement reaction where the two solutions of the salts are mixed, the insoluble salt calcium oxalate is precipitated. The net ionic equation for the reaction is shown below:
Ca²⁺(aq) + C₂O₄²⁻(aq) ----> CaC₂O₄(s)
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
Rosa uses a microscope to look at a group of cells. She sees that the cells are joined together, so she knows that they are from one organism. She also sees that all of them have cell walls. Rosa could be looking at which type of cells?
Answer:
Mushroom cells
Explanation:
They are mushroom cells because they are together.
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.
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
If air has a density of 1.225 kg/m3, what is the mass of the air in a hot air balloon that has a volume of 2,800
m3?
Answer:
The answer is 3430 kgExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volumeFrom the question
volume = 2800 m³
density = 1.225 kg/m³
We have
mass = 2800 × 1.225
We have the final answer as
3430 kgHope this helps you
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.
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:
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.
marshmallow is costly, what type of food is marshmallow?
a.suspension b.solution c.colloid
Answer:
b solution
Explanation:
