Answer:
The necklace is fake.
The necklace is made up of copper.
Explanation:
The following data were obtained from the question:
Mass of the necklace = 21.3 g
Volume of water = 5 mL
Volume of water + Necklace = 7.4 mL
To identify the composition of the necklace, we shall determine the density of the necklace.
This can be obtained as follow:
We'll begin by calculating the volume of the necklace. This can be obtained as shown below:
Volume of water = 5 mL
Volume of water + Necklace = 7.4 mL
Volume of Necklace =.?
Volume of Necklace = (Volume of water + Necklace) – (Volume of water)
Volume of Necklace = 7.4 – 5
Volume of Necklace = 2.4 mL
NOTE:
1 mL = 1 cm³
Therefore,
Volume of Necklace = 2.4 mL = 2.4 cm³
Finally, we shall determine the density of the necklace as follow:
Mass of the Necklace = 21.3 g
Volume of Necklace = 2.4 cm³
Density of Necklace =?
Density = mass /volume
Density = 21.3 / 2.4
Density = 8.87 g/cm³
Therefore, the density of the necklace is 8.87 g/cm³.
From the question given above, we were told Jacy bought a gold necklace.
But comparing the density of necklace to the densities given above the necklace is obviously made of copper material.
Therefore, Jacy bought a fake gold necklace.
What does a cell nucleus do?
Select one:
a. control everything the cell does
b. surround the cell
c. hold important chemicals the cell needs
d. protect the cell.
Answer:
a. control everything the cell does
Explanation:
the nucleus is like the brain of the cell
an object has a mass of 14g and a volume 3.5 mL. what is the density of the object ?
Given :
Mass of object , M = 14 g .
Volume of object , V = 3.5 mL .
To Find :
The density of the object .
Solution :
Density of an object is given by :
[tex]Density=\dfrac{Mass}{Volume}\\\\\rho=\dfrac{M}{V}\\\\\rho=\dfrac{14}{3.5}\ g/mL\\\\\rho=4\ g/mL[/tex]
Therefore , the density is 4 g/mL .
Hence , this is the required solution .
indigestion tablets neutralise acid in the stomach. what does this tell you about indigestion tablets?
Answer:
It is basic.
Explanation:
Bases can neutralize acids.
What is the hardness (HB) of each of the alloys?
(a) 0.25 wt%C with spheroid:te,
(b) 0.25 wt%C with coarse pearlite,
(c) 0.60 wt%C with fine pearlite, and
(d) 0.60 wt%C with coarse pearlite.
Answer:
A) 62.5 HB
B) 75 HB
C) 95 HB
D) 90 HB
Explanation:
From the attached animated figure, we can trace the values of hardness (HB) for each of the alloys.
The scale we are using in the attachment to read our values for HB is the HRB scale that shows the Rockwell hardness on the right hand side.
A) For 0.25 wt%C with spheroidite, Tracing the line out on the green curve and reading the scale on the right, the hardness is approximately 62.5 HB
B) For 0.25 wt%C with coarse pearlite, Tracing the line out on the blue curve and reading the scale on the right hand side, the hardness is approximately 75 HB
C) For 0.60 wt%C with fine pearlite, Tracing the line out on the red curve and reading the scale on the right hand side, the hardness is approximately 95 HB
D) For 0.60 wt%C with coarse pearlite. Tracing the line out on the blue curve and reading the scale on the right hand side, the hardness is approximately 90 HB
What are the best practices for safely handling waste in the lab? Select one or more: Check labels or instructions before any disposal. Always wear appropriate Personal Protective Equipment. Place any paper towels from the clean-up in the trash. Remove gloves for better manipulation of the waste containers
Answer:
Consult labels or instructions before disposing of it. Always wear the proper personal protective equipment. Put all cleaning paper towels in the trash
Explanation:
Gloves should never be removed when disposing of waste, since these can contain infected fluids or even cultivated microorganisms that are pathogens for our lives and can enter through a lesion of the continuity solution of the epithelium in our hands.
In other words, if there is a wound, and it is contaminated with waste by not wearing gloves, the risk of contracting diseases is much greater.
Which four practices are examples of how humans use science?
A. Making decisions that help humans survive
OB. Developing technologies that help humans thrive
C. Developing explanations based on facts
D. Imagining entertaining stories that explain observations
O E. Gathering facts that explain natural events
Answer:
A. Making decisions that help humans survive
B. Developing technologies that help humans thrive
C. Developing explanations based on facts
E. Gathering facts that explain natural events
Explanation:
The above are examples of the practices of how humans use science.
Science has been of tremendous help to humans in making decisions that make humans survive and develop technologies that help humans thrive. It has helped to gather and develop explanations that are based on facts. It has helped to explain natural events.
Cuci
what is the formula?
Answer:
Copper(I) chloride, commonly called cuprous chloride, is the lower chloride of copper, with the formula CuCl. The substance is a white solid sparingly soluble in water, but very soluble in concentrated hydrochloric acid. Impure samples appear green due to the presence of copper(II) chloride.
Explanation:
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When 14.8 g KOH is dissolved in 85.6 g of water in a coffee-cup calorimeter, the temperature rises from 19.3 °C to 32.76 °C. What is the enthalpy change per gram of potassium hydroxide dissolved in the water?
Answer:
This question is incomplete, the complete question is; assuming that the solution has a specific heat of 4.18 J/g°C
The answer is 381.67 J/g
Explanation:
Enthalpy change denoted by ΔH can be calculated using the formula;
ΔH = m × c × ΔT
Where; m= mass of reactants
c= specific heat
ΔT = change in temperature
ΔT = T2 - T1
ΔT = 32.76 - 19.3
ΔT = 13.46 °C
mass of reactants= 85.6 + 14.8 = 100.4g, c = 4.18J/g°C
Hence; ΔH = m × c × ΔT
ΔH = 100.4 × 4.18 × 13.46
ΔH = 5648.78J
Enthalpy change per gram of potassium hydroxide dissolved in the water is;
ΔH = 5648.78/14.8
ΔH = 381.67 J/g
The enthalpy change per gram of potassium hydroxide dissolved in the water is 382 J/g
How to determine the heat Mass (M) = 14.8 + 85.6 = 100.4 gInitial temperature (T₁) = 19.3 °C Final temperature (T₂) = 32.76 °CChange in temperature (ΔT) = 32.76 – 19.3 = 13.46 °C Specific heat capacity (C) = 4.184 J/gºC Heat (Q) =?
Q = MCΔT
Q = 100.4 × 4.184 × 13.46
Q = 5654.19 J
How to determine the enthalpy change ΔHHeat (Q) = 5654.19 JMass of KOH (m) = 14.8 gEnthalpy change (ΔH) =?ΔH = Q / g
ΔH = 5654.19 / 14.8
ΔH = 382 J/g
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An advertisement for a new fish food claims that lab studies show that fish grew three inches in three weeks while eating the food. Travis wondered if the food was worth the extra cost.
Answer: To evaluate the claim in the advertisement, Travis should look at the data for the control group to see how much the fish grew without the new food.
Explanation:
How many neutrons are there in 8 molecules of
[tex] \frac{19}{9} f2[/tex]
Answer:
128 neutrons
Explanation:
How many neutrons are there in 8 molecules of [tex]^{19} _9 F_2[/tex]?
Step 1: Calculate the number of neutrons in 1 atom of F.
The atomic number (z) of F is 9 and its mass number (A) is 19. We can calculate the number of neutrons using the following expression.
n⁰ = A - Z = 19 - 9 = 10
Step 2: Calculate the number of neutrons in 1 molecule of F₂.
1 molecule of F₂ contains 2 atoms of F. The number of neutrons in 1 molecule of F₂ is:
(8 n⁰/1 atom F) × (2 atom F/1 molecule F₂) = 16 n⁰/1 molecule F₂
Step 3: Calculate the number of neutrons in 8 molecules of F₂
8 molecule F₂ × 16 n⁰/1 molecule F₂ = 128 n⁰
A ratio that compares the length and width of a garden is what type of model?
A. Physical
B. Conceptual
C. Computer
D. Mathematical
Answer:
D. Mathematical
Explanation:
11. A sample contains 25% water and weighs 201 grams. Determine the grams of water in the
sample.
Answer:
[tex]m_{water}=50.25g[/tex]
Explanation:
Hello,
In this case, considering that the by-mass percent of water is:
[tex]\% m/m=\frac{m_{water}}{m_{sample}}*100\%[/tex]
Given such percent and the mass of the sample, we can find the mass of water in grams in the sample by solving for it as shown below:
[tex]m_{water}=\frac{\%m/m*m_{sample}}{100\%}\\ \\m_{water}=\frac{25\%*201g}{100\%}\\ \\m_{water}=50.25g[/tex]
Best regards.
Describe each highlighted bond in terms of the overlap of atomic orbitals. (If the highlighted bond is not a pi bond, select the blank option from the dropdown menu.) Compound 1: Molecular orbital type: _________ Atomic orbitals in the sigma bond: _________ Atomic orbitals in the pi bond: _________ Compound 2: Molecular orbital type: _________ Atomic orbitals in the sigma bond: _________ Atomic orbitals in the pi bond: _________
The image of the bonds are missing, so i have attached it.
Answer:
A) - Sigma bond
-Sp³ and Sp³
- None
B) - Sigma and pi bond
- Sp² of C and p of O
- p of C and P of O
Explanation:
A) For compound 1;
- the molecular orbital type is sigma bond due to the end-to-end overlapping.
- Atomic orbitals in the sigma bond will be Sp³ and Sp³
- Atomic orbitals in the pi bond would be nil because there is no pi bond.
B) For compound 2;
- the molecular orbital type is sigma and pi bond
-Atomic orbitals in the sigma bond would be Sp² of C and p of O
- The Atomic orbitals in the pi bond will be; p of C and p of O
The particles of a gas inside a balloon are experiencing an increase in their average kinetic energy and the number of collisions with the wall of the balloon. What is the most likely outcome? higher gas pressure inside the balloon higher air pressure outside the balloon a decrease in gas temperature inside the balloon a large increase in air temperature outside the balloon
The higher Gas pressure inside the balloon. Hence, option A is correct.
How is kinetic energy related to temperature?In a molecule, the kinetic energy existing is "directly proportional" to the temperature of the molecule. If one of the values increases, then the other value also increases and vice-versa.
The higher Gas pressure inside the balloon. As the number of collisions with the wall of the balloon increases, the pressure inside increases.
Hence, option A is correct.
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1. How many ATOMS of carbon are present in 7.48 grams of carbon monoxide ?
Answer:
The answer is 1.61 × 10²³ atoms
Explanation:
To determine number of atoms, we will use the formula below
Number of atoms = number of moles (n) × avogadro's constant (6.02 x 10²³)
n was not provided, hence we will solve for n
n = mass/ molar mass
molar mass of carbon monoxide, CO (where C is 12 and O is 16) is 12 + 16 = 28
mass was provided in the question as 7.48
n = 7.48/28
n = 0.267
Hence,
number of atoms = 0.267 × 6.02 x 10²³
= 1.61 × 10²³ atoms
A runner averages 8 minutes and 25 seconds per mile. What is her average velocity in miles per hour?
8 minutes and 25 seconds is the same as 8.25 in decimal form.
Divide by 60 minutes.
60 / 8.25 = 7.27 miles per hour
Best of Luck!
Which statement explains why carbon-14 dating cannot be used to date ancient rocks?
Carbon-14 decays at a varying rate.
Carbon-14 decays relatively quickly.
Carbon-14 can be used only to date the remains of organisms.
Carbon-14 has a half-life that is much longer than potassium.
Answer:
its, b
Explanation:
took the test on e2020
Carbon-14 dating cannot be used to date ancient rocks because:
B. Carbon-14 decays relatively quickly.
Carbon-14 dating:It is a method for tracking down the time of natural materials, like wood, in light of their substance of radioactive carbon. Also, it is a technique for estimating the time of natural matter by investigating its carbon content.
The decay takes place around 55,000 years i.e half the amount of the radioisotope present at any given time.
Thus, option B is correct.
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A laser pointer used in the classroom emits light at 5650 Å, at a power of 4.00 mW. (One watt is the SI unit of power, the measure of energy per unit of time. 1 W = 1 J/s). How many photons are emitted from the pointer in 115 seconds?
Answer:
n = 1.3 x 10¹⁸ photons
Explanation:
First we need to calculate the amount of energy released in given time:
E = Pt
where,
E = Energy = ?
P = Power = 4 mW = 0.004 W
t = time = 115 s
Therefore,
E = (0.004 W)(115 s)
E = 0.46 J
Now, this energy can be given in forms of photons as:
E = nhc/λ
where,
n = No. of photons = ?
h = Plank's Constant = 6.626 x 10⁻³⁴ J.s
c = speed of light = 3 x 10⁸ m/s
λ = wavelength of light = 5650 x 10⁻¹⁰ m
Therefore,
0.46 J = n(6.626 x 10⁻³⁴ J.s)(3 x 10⁸ m/s)/(5650 x 10⁻¹⁰ m)
n = (0.46 J)/(3.5 x 10⁻¹⁹ J)
n = 1.3 x 10¹⁸ photons
Answer:
1.308 x 10¹⁸ photons were emitted from the laser pointer.
Explanation:
Given;
wavelength of the photon, λ = 5650 Å = 5650 x 10⁻¹⁰ m
power emitted by the source, P = 4 mW = 4 x 10⁻³ W
time of photon emission, t = 115 s
The energy of a single photon is given by;
E = hf
f = c / λ
[tex]E = \frac{h c }{\lambda}[/tex]
where;
c is speed of light = 3 x 10⁸ m/s
h is Planck's constant = 6.626 x 10⁻³⁴ Js
[tex]E = \frac{(6.626 *10^{-34}) (3*10^8) }{5650*10^{-10}}\\\\ E = 3.518*10^{-19} \ J[/tex]
Energy of the source (laser pointer) = P x t
= (4 x 10⁻³ W) (115 s )
= 0.46 J
If no energy is lost, then emitted energy by the source must be equal to total energy of then photons;
[tex]E_T = n E_{photon}\\\\n = \frac{E_T}{E_{photon}}\\\\n = \frac{0.46}{3.518*10^{-19}}\\\\n = 1.308*10^{18} \ photons[/tex]
Therefore, 1.308 x 10¹⁸ photons were emitted from the laser pointer.
What determines the reactivity of an akali metal?
Answer:
The number of valence electrons determines an element's reactivity, or how likely the element is to react with other elements.
Explanation:
The best thermometer to use where temperatures drop below -39°C (-38.2°F) is:_______.
Answer:
The best thermometer to use for this temperature is the alcohol-in-a -glass thermometer.
Explanation:
The alcohol thermometer is a type of thermometer which uses ethanol as its thermometric liquid. This has some advantages at low temperatures because ethanol freezes at about −114.9 °C that is (−174.82 °F).
Due to its low freezing point, it can still function effectively as a thermometric liquid, expanding and contracting properly based on the applied heat, when dealing with temperature measurements that are at about -38.2°F.
Can someone please help me with this? :(
Answer:
Bo
Explanation:
Bo is not a element
Give the charge on the transition metal of each of the following compounds:
A. Au2SO4
B. Fe2(CrO4)3
C. Zn(OH)2
Enter your answer as +1, +2, etc.
Au
type your answer...
Fe
type your answer...
Zn
type your answer...
In Au₂SO₄, the charge on each gold atom is +3.
The charge on the transition metal gold (Au) in Au₂SO₄ can be determined by considering the overall charge of the compound and the charges of the other ions present. In this case, the sulfate ion carries a charge of -2.
Charge on Au: +3
In Fe₂(CrO₄)₃, the transition metal iron (Fe) is present. The compound contains two iron atoms. To determine the charge on each iron atom, the charges of the other ions in the compound. The chromate ion carries a charge of -2, and the compound as a whole is neutral.
Charge on Fe: +3
The transition metal zinc (Zn) is present in Zn(OH)₂. To determine the charge of the zinc ion, to consider the charges of the other ions. The hydroxide ion (OH-) carries a charge of -1. Since there are two hydroxide ions, their combined charge is -2.
Charge on Zn: +2
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Identify the characteristics of a good recrystallization solvent. Select one or more: Dissolves a chemical sample well at high temperatures. Is not an organic liquid with a low boiling point. Does not dissolve a chemical sample well at low temperatures. Does not dissolve a chemical sample well at high temperatures. Dissolves a chemical sample well at low temperatures. g
Answer:
Dissolves a chemical sample well at high temperatures.
Does not dissolve a chemical sample well at low temperatures.
Explanation:
Recrystallization involves the dissolution of the solute in a solvent at high temperature. As the solution cools, it becomes saturated and the solute crystallizes out of the solution.
A good recrystallization solvent must only dissolve the solute at high temperature and must not dissolve it at low temperature. Hence, these are the two conditions required for any good recrystallization solvent.
Pb-214 in beta decay
Lead 214 emits then beta electrons to transform into bismuth 214 and polonium 214, which produces lead 210 through the emission of a third alpha particle. This series of transformations take place in a time span roughly equal to an hour.
Hope this helps, if I am right, brainliest? :))))
How are most meteoroids formed? A. As the Sun burns, it throws off small, solid particles at a regular rate which are launched into the Solar System. B. They are created in the explosions that occur when stars die and eventually reach the Solar System. C. They are small pieces that are left over from the formation of the Solar System. D. They are small pieces of debris that are the result of collisions of asteroids, comets, moons, and even planets within the Solar System. Will give brainlist
Answer:
It is no. D
Explanation:
Many meteoroids are formed from the collision of asteroids, which orbit the sun between the paths of Mars and Jupiter in a region called the asteroid belt.
What is the difference between pure and applied chemistry?
Answer:
Explanation:
The major difference between pure and applied chemistry is the purpose and intent of the study.
Pure chemistry deals with the study of matter, matter transformations, and interactions between the different materials of the world, for only the sake of gaining empirical knowledge about the various substances that exist in the world. It does not really seek to apply this knowledge to do anything industrial.
Applied chemistry is the study of chemistry with the aim of utilizing this knowledge to solve the various problems that man faces. This approach of study is not for knowledge sake alone, rather it is for industrial application
The major difference between pure and applied chemistry is the purpose and intent of the study.
Pure chemistry deals with the study of matter, matter transformations, and interactions between the different materials of the world, for only the sake of gaining empirical knowledge about the various substances that exist in the world. It does not really seek to apply this knowledge to do anything industrial.
Applied chemistry is the study of chemistry with the aim of utilizing this knowledge to solve the various problems that man faces. This approach of study is not for knowledge sake alone, rather it is for industrial application.
Thus,the major difference between pure and applied chemistry is the purpose and intent of the study.
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When Z-4,5-dimethyloct-4-ene is treated with hydrogen chloride, HCl, the result is:________.
A. 4 stereoisomers
B. None of these
c. a pair of diastereomers
D. a racemic mixture OS a meso compound
Answer:
The correct option is c
Explanation:
The chemical equation for the reaction of Z-4,5-dimethyloct-4-ene and HCl is shown on the first uploaded image
Now looking at the product we see that there are two who has four different groups attached to them this carbon are known as chiral carbons hence the product formed is a pair of diastereomers
Alkynes are reduced to trans alkenes by a process called dissolving metal reduction. The reaction uses sodium or lithium metal as the reducing agent and liquid ammonia as the solvent. The method is specific in the formation of trans alkenes from alkynes. The method involves two successive transfers of single electrons from the alkali metal to the triple bond, with abstraction of protons from the ammonia solvent.Draw curved arrows to show the movement of electrons in this step of the mechanism.Arrow-pushing Instructions
Answer:
Explanation:
The movement of the electrons is illustrated in the picture attached to this answer. It is a four-step reaction mechanism.
First STEP: The first step involves the transfer of an electron from sodium to form a radical anion.
Second STEP: This radical anion then removes a proton/hydrogen from ammonia in a bid to neutralize itself (hence the hydrogen becomes bonded to the anion).
Third STEP: The sodium (from NaNH₂ formed) transfers an electron again to produce a vinyl carbanion.
Fourth STEP: The carbanion then removes a proton/hydrogen from ammonia (like in the second step) to form a neutral trans-alkene.
NOTE: The circled numbers denote each step while the mechanism on the left represents the use of any alkyl group (R and R') while the mechanism on the right assumes both alkyl groups are methyl. Hence, 2-butyne started the reaction and the final product was trans-2-butene.
Explain why CaCl2 is likely to have properties similar to those of CaBr2
Answer:
Because both compounds (CaCl2 and CaBr2) contain elements (bromine and chlorine) from the same group (group 7)
Explanation:
Elements are organized into groups on the periodic table based on the number of valence electrons contained in their outermost shell. These elements in the same group i.e. same number of valence electrons, will behave in a similar manner chemically.
CaCl2 and CaBr2 are two compounds that contains elements (Chlorine and Bromine) from the same group, which is group 7. Elements in group 7 are called HALOGENS and have 7 valence electrons in their outermost shell.
Bromine (Br) and Chorine (Cl) are responsible for the similarity in the properties of CaCl2 and CaBr2 because the Chlorine and Bromine contained in them will cause them to react similarly and behave similarly in the presence of other compounds.
(b) Draw the structure of the products when cyclopentene is reacted with:
(i) Cold alkaline KMnO4
Answer:
See explanation and image attached
Explanation:
When an alkene is reacted with cold, dilute and alkaline KMnO4, the product of the reaction is a 1,2-diol (vicinal diol). The products exhibit a “syn” stereochemistry with the addition of the two -OH groups to the same side of the alkene.
The reaction of cyclopentene with cold, dilute, alkaline KMnO4 is shown in the image attached.
In the given query, when cyclopentene is reacted with cold alkaline [tex]\rm KMnO_4[/tex], the product formed is cis-1,2-cyclopentanedicarboxylic acid (image attached below).
The reaction proceeds via oxidative cleavage of the double bond in cyclopentene to form two carboxylic acid groups.
The potassium permanganate ([tex]\rm KMnO_4[/tex]) acts as a strong oxidizing agent and cleaves the double bond to form two carboxylic acid groups.
The reaction can be represented as follows:
Cyclopentene + cold alkaline [tex]\rm KMnO_4 \rightarrow[/tex] cis-1,2-cyclopentanedicarboxylic acid
Therefore, the product, cis-1,2-cyclopentanedicarboxylic acid (refer to the attached image below), has a cyclopentane ring with two carboxylic acid groups attached to the 1 and 2 carbons, respectively.
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