Each student in a class placed a 2.00 g sample of a mixture of Cu and Al in a beaker and placed the beaker in a fume hood. The students slowly poured 15.0 mL of 15.8 M HNO3 into their beakers. The reaction between the copper in the mixture and the HNO3 is represented by the equation above. The students observed that a brown gas was released from the beakers and that the solutions turned blue, indicating the formation of Cu 2. The solutions were then diluted with distilled water to known volumes. The students determined that the reaction produced 0.010 mol of Cu(NO3)2. Based on the measurement, what was the percent of Cu by mass in the original 2.00 g sample of the mixture

Answers

Answer 1

Answer:

Percentage mass of copper in the sample = 32%

Explanation:

Equation of the reaction producing Cu(NO₃) is given below:

Cu(s)+ 4HNO₃(aq) ---> Cu(NO₃)(aq) + 2NO₂(g) + 2H₂O(l)

From the equation of reaction, 1 mole of Cu(NO₃) is produced from 1 mole of copper. Therefore, 0.010 moles of Cu(NO₃) will be produced from 0.010 mole of copper.

Molar mass of copper = 64 g/mol

mass of copper = number of moles * molar mass

mass of copper = 0.01 mol * 64 g/mol = 0.64 g

Percentage by mass of copper in the 2.00 g sample = (0.64/2.00) * 100%

Percentage mass of copper in the sample = 32%


Related Questions

Which of the following is the correct formula used for calculating Speed?


Speed = distance / time

Speed = time / distance

Speed = mass / time

Answers

Answer:

A- Speed = distance/time

Explanation:

Would make sense and that's what I remember

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

Answers

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

liqued in which a substance dissolve​

Answers

Answer: Water as its the universal solvent

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.

Answers

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

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

Answers

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

) If 1 vitamin C tablet weighs 475 mg how much vitamin C is in that 1 tablet based on your
calculations?

Answers

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

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?

Answers

Answer:

Mushroom cells

Explanation:

They are mushroom cells because they are together.

Complete and balance each of the following equations for acid-base reactions.
H3PO4(aq) + Sr(OH)2(aq) →

Answers

Explanation:

Sr(OH)2 + H3PO4 = Sr3(PO4)2 + H2O - Chemical Equation Balancer.

Answer:

3Sr(OH)2 + 2H3PO4 → Sr3(PO4)2 + 6H2O

Explanation:

please check the image for accurate answer

which of the substances created a chemical change

Answers

Answer:

It is one and two

Explanation:

When you burn something it lights up  

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

Answers

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:

brainly.com/question/2396573

#SPJ1

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?

Answers

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.

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.

Answers

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)

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

Answers

Answer:

25.6 Explanation:

A chemist needs to create a series of standard Cu2+(aq) solutions for an absorbance experiment. For the first standard, he uses a pipet to transfer 10.00 mL of a 2.61 M Cu2+(aq) stock solution to a 250.0 mL volumetric flask, and he adds enough water to dilute to the mark. He then uses a second pipet to transfer 10.00 mL of the second solution to a 100.0 mL volumetric flask, and he adds enough water to dilute to the mark. Calculate the concentration of the Cu2+(aq) solution in the 100.0 mL volumetric flask. concentration: M

Answers

Answer:

0.01 M

Explanation:

The chemist is performing a serial dilution in order tyo obtain the calibration curve for the instrument.

First we must obtain the concentration of the solution in the 250ml flask from

C1V1 = C2V2

Where;

C1 = concentration of the stock solution

V1 = volume of the stock solution

C2 = concentration of the diluted solution

V2= volume of the diluted solution

2.61 × 10 = C2 × 250

C2 = 2.61 × 10/250

C2 = 0.1 M

Hence for solution in 100ml flask;

0.1 × 10 = C2 × 100

C2 = 0.1 × 10/100

C2 = 0.01 M

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?

Answers

Answer:

The answer is 3430 kg

Explanation:

The mass of a substance when given the density and volume can be found by using the formula

mass = Density × volume

From the question

volume = 2800 m³

density = 1.225 kg/m³

We have

mass = 2800 × 1.225

We have the final answer as

3430 kg

Hope 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.

Answers

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.

If you weigh 118 lbs, how many kilograms is this

Answers

the answer would be: 53.524 kg

Answer:

the answer is 53.524 kg

The elwments in group 17 of the periodic table are all halogens. All halogens have the same ______.
A. Atomic number
B. Atomic mass
C. Number of possible isotopes
D. number of valence electrons ​

Answers

Group 17 elements called halogens . All halogens have the same number of valence

electrons

They all have the same number of valence electrons. So the answer is D

1.8 x 1022 atoms of Rn to moles of Rn​

Answers

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

By which method is heat transferred in a microwave oven?

Conduction
Convection
Evaporation
Radiation

Answers

Answer:

the answer is radiation.

because the microwave is a form of radiation.

give me brainlyest if this was helpful to you otherwise dont.

Answer: D

Explanation:

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.

Answers

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:

2. What is an example of an object that affects gravity on Earth?

Answers

Answer:

The moon

Explanation:

The moon pulls on the earth, causing the tides to raise as the water is being pulled by the moon.

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.

Answers

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.

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

Answers

2-bromo-2-methylpropane should have reacted faster.

how many protons electrons and nuetrons does as have​

Answers

As (Arsenic) has 33 protons as it is the atomic # on the periodic table and 33 electrons and 42 neutrons.

A student loaded a mixture of compounds onto a silica gel column using 5 mL of dichloromethane as the loading solvent. After running the column using petroleum ether as the eluant and collecting 8 fractions, the student analyzed the contents by TLC to find that all of the compounds in the mixture came off in the first two fractions. In addition, no separation was observed. Choose the statement that BEST describes the error. The sample should be loaded using a maximum 1 mL of CH2Cl2. Petroleum ether was the incorrect eluant. A more polar solvent should have been used. The student should re-run the TLC. It was obviously performed incorrectly. The student packed the column incorrectly.

Answers

Answer:

Petroleum ether was the incorrect eluant.

Explanation:

In column chromatography, there must be a mobile phase (eluant) and a stationary phase(adsorbent column). The mobile phase in this case is petroleum ether while the stationary phase is silica gel.

If no separation is observed, then it simply means that the wrong choice of mobile phase(eluant) was made. If a better choice of eluant is made, it can effectively achieve the separation of the mixture. The components of the mixture have a great affinity towards the petroleum ether hence they moved rapidly through the column and separation was not achieved.

Which property is not a physical property?
A. Color
B. Ability to Burn
C. Density
D. Melting Point

Answers

i’m not 100% sure but my guess is color or density

Answer: Ability to Burn

Explanation: I TOOK THE TEST

marshmallow is costly, what type of food is marshmallow?
a.suspension b.solution c.colloid​

Answers

Answer:

b solution

Explanation:

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.

Answers

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

Material
Appearance of the material,
including its color and state
baking soda
baking powder
Salt
sugar
flour
vinegar
cooking oil

Answers

Baking Soda; (dusty) (white and solid)

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

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