Answer:
However copper ore is a finite resource and it makes sense to conserve ore by recycling. It is cheaper to recycle old copper than to mine and extract new copper.
What is the mass number of an atom that has 19 protons, 19 electrons, and 20 neutrons?
Answer:
[tex]\boxed {\boxed {\sf 39}}[/tex]
Explanation:
The mass number of an atom can be found by adding the number of protons and neutrons.
[tex]mass \ number =protons + neutrons[/tex]
There are 19 protons and 20 neutrons.
[tex]protons=19 \\neutrons=20[/tex]
[tex]mass \ number= 19+20[/tex]
[tex]mass \ number =39[/tex]
The mass number of this atom is 39
in which beakers are the particles moving the most slowly
Answer:
A and D
Explanation:
3. Once magnesium (Mg) gives up electron(s) to become an ion, it will become
Answer:
Option B. Cation that is smaller than the original atom.
Explanation:
Magnesium is a divalent element. This implies that magnesium can give up 2 electrons to become an ion (cation) as shown below:
Mg —> Mg²⁺ + 2e¯
Next, we shall write the electronic configuration of magnesium atom (Mg) and magnesium ion (Mg²⁺). This can be written as follow:
Mg (12) = 2, 8, 2
Mg²⁺ (10) = 2, 8
From the above illustration, we can see that the magnesium atom (Mg) has 3 shells while the magnesium ion (Mg²⁺) has 2 shells.
This simply means that the magnesium ion (Mg²⁺) i.e cation is smaller that the original magnesium atom (Mg).
Which of the following is true regarding the atoms involved in a chemical reaction?
Which of the following covalent bonds is the most polar (i.e., highest percent ionic character)?
A) Al I
B) Si I
C) Al Cl
D) Si Cl
E) Si P
Answer:
answer d is correct that works
Exactly 56 grams of iron is mixed with 156 grams of oxygen. The elements are heated and they react. What best describes which remains after the reaction is complete?
Answer:
Explanation:
The chemical expression for the reaction between iron and oxygen is:
4Fe(s) + 3O₂ (g) [tex]\to[/tex] 2Fe₂O₃ (s)
The number of moles of Fe = mass of Fe/ molecular mass of Fe
The number of moles of Fe = 56 g/ 55.845 g/mol
The number of moles of Fe = 1.002 moles of Fe
The number of moles of oxygen = mass of oxygen/ molecular mass of oxygen
The number of moles of oxygen = 156 g /32 g/mol
The number of moles of oxygen = 4.875 moles of oxygen
Assume that Fe is the limiting reactant, the number of Fe₂O₃ can be calculated as:
moles of Fe₂O₃ = 1.002 mole of Fe × 2 moles of Fe₂O₃/ 4 moles of Fe
moles of Fe₂O₃ = 0.501 mole of Fe₂O₃
Assume that O₂ is the limiting factor, the number of Fe₂O₃ is:
moles of Fe₂O₃ = 4.875 moles of O₂ × 2 moles of Fe₂O₃/ 3 moles of O₂
moles of Fe₂O₃ = 3.25 mole of Fe₂O₃
Thus, after the reaction is complete, Fe and O₂ contain different moles of Fe₂O₃. Only Fe gets consumed in the reaction and it is the limiting factor.
Scientists who are investigating what has happened over the years to the people who were exposed to radiation during the 1986 Chernobyl nuclear disaster are conducting what type of study
Answer:
Observational study
Explanation:
An investigation of what happened over the years to the people who were exposed to radiation during the 1986 Chernobyl nuclear disaster would be termed an observational study because it will require observing subjects and finding out if there is a kind of correlating factor in the subjects that could indicate the level of exposure to the nuclear radiation.
There are basically two types of research studies:
1. Observational studies
2. Experimental studies
Observational studies involve just the observation of subjects and trying to find out some correlation factors. This kind of study could be prospective when it deals with what could happen in the future based on certain factors or retrospective when it considers what has already happened. An observational study can be cross-sectional, case-only, case-control, or cohort study.
Experimental studies are also referred to as randomized or controlled trial studies. Here, subjects are grouped and each group receives a different treatment in order to isolate the effect of a particular factor or variable relating to the treatment.
What two atoms are held together by a covalent bond in NaHCO3
Answer: covalent bond is the force of attraction that holds together two atoms that share a pair of valence electrons. Covalent bonds form only between atoms of nonmetals. The two atoms that are held together in a covalent bond may be atoms of the same element or different elements.
Explanation:
A container holds 3.41×10−3mol of carbon dioxide (CO2). After the addition of 8.41×10−4mol of carbon dioxide, the volume of the container increases to 95.2mL, with the temperature and pressure remaining constant. What was the initial volume of the container?
Answer:
76.366
Explanation:
Knewton answer is 76.4
Answer:
76.4mL
Explanation:
First, calculate the final number of moles of carbon dioxide (n2) in the container.
n2 = n1+n added = 3.41×(10^-3) mol+8.41×(10^-4) mol = 4.25×(10^-3) mol
Rearrange Avogadro's law to solve for V1.
V1 =(V2×n1)/n2
Substitute in the known values for n1, V2, and n2.
V1 = (95.2mL×(3.41×10^-3 mol))/(4.25×(10^-3) mol)=76.4mL
So the initial volume is 76.4mL.
KOH (aq) + HNO(little3) (aq) = KNO(little 3) (aq) + H20 (1)
The reaction already balanced
Further explanationEqualization of chemical reactions can be done using variables. Steps in equalizing the reaction equation:
• 1. gives a coefficient on substances involved in the equation of reaction such as a, b, or c, etc.
• 2. make an equation based on the similarity of the number of atoms where the number of atoms = coefficient × index (subscript) between reactant and product
• 3. Select the coefficient of the substance with the most complex chemical formula equal to 1
For gas combustion reaction which is a reaction of hydrocarbons with oxygen produces CO₂ and H₂O (water vapor). can use steps:
Balancing C, H and the last O
Reaction
KOH (aq) + HNO₃ (aq) ⇒ KNO₃ (aq) + H₂0 (l)
give coefficientaKOH (aq) + bHNO₃ (aq) ⇒ KNO₃ (aq) + cH₂0 (l)
K : left = a, right = 1⇒a=1
N : left = b, right =1, b=1
H: left = a, right a+b=2c⇒1+1=2c⇒2=2c⇒c=1
KOH (aq) + HNO₃ (aq) ⇒ KNO₃ (aq) + H₂0 (l)⇒ already balanced
Explain your thoughts on whether or not using solely IR is a good method to make positive IDs of chemicals.
Answer:
No, IR should not soely be used to identify molecules
Explanation:
IR is a method that identifies the functional groups in a molecule by deducing the frequency of stretching and vibration of bonds. Each peculiar type of bond has a frequency for the vibration of each bond represented on the IR spectrum.
However, one method is never enough to identify a compound. A combination of methods must always be used to clear up ambiguities arising from overlapping IR frequencies. Also, interpretation of the nuanced peaks of the fingerprint region in IR spectra is quite challenging and only gives a fair idea of the functional groups present in the compound.
Therefore other methods such as NMR, UV-VISIBLE etc should also be involved in the identification of compounds.
What is the total pressure of mixture in which H2 and CO exerted 31mmHg and 510mmHg respectively
Answer:
Ans: 541 mmHg
Explanation:
given:
H2 = 31mmHg
CO= 510mmHg
get the sum
31+510=541
Which of the following best defines climate)_( Short-term atmospheric conditions of a region Ob The weather pattern of an area over two weeks or less Average weather conditions of a region over the long term Od A pattern of weather that never changes
Answer:
Average weather conditions of a region over the long term
Explanation:
Climate is the long-term average of weather, typically averaged over a period of 30 years. More rigorously, it denotes the mean and variability of meteorological variables over a time spanning from months to millions of years.
How many moles of water are produced if 5.43 mol PbO2 are consumed?
10.86 moles of water are produced
Further explanationA reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products.
Reaction
Pb + PbO₂ + 2H₂SO₄ ⇒ 2PbSO₄ + 2H₂O ( a car battery reaction)
From the equation :
mol ratio PbO₂ : H₂O = 1 : 2⇒ 1 mol PbO₂ produces 2 mol H₂O
so for 5.43 mol PbO₂ consumed, mol H₂O :
[tex]\tt 2\times 5.43=10.86~moles[/tex]
Answer:
10.9
Explanation:
edge 2020
A particular solution of hydrochloric acid is 3.0 M. How many moles of hydrochloric acid are present in 22.7 mL of this solution?
Answer:
0.0681 HCl moles
Explanation:
First we convert 22.7 mL to liters:
22.7 mL * [tex]\frac{1L}{1000mL}[/tex] = 0.0227 LThen we use the definition of molarity:
molarity = moles / litersmoles = molarity * litersmoles = 3.0 M * 0.0227 Lmoles = 0.0681 molesSo there are 0.0681 hydrochloric acid moles in 22.7 mL of a 3.0 M HCl solution.
A rigid container filled with a gas is placed in ice (ex. nalgene bottle). What will happen to the pressure of the gas? What do you think will happen to the volume?(Graph)
Explanation:
The pressure will decrease but the volume remains constant
What can be done to remove a magnetic force around an electromagnet
made of a coiled copper wire wrapped around an iron bar and connected to a
power source?
O A. Uncoil the wire.
B. Remove the iron bar.
C. There is always a small magnetic force around the wire.
D. Stop the current.
What is the primary means through which the Sun warms Earth?
a
b
Fluctuation of subatomic particles.
Fluctuation of gravitational fields.
C Transfer of energy through conduction.
D Transfer of energy by electromagnetic waves.
Answer:
D
Explanation:
Radiation - radiation is transfer of energy by electromagnetic waves
The sun warms the earth through the transfer of energy by electromagnetic waves. Therefore, option (D) is correct.
What are electromagnetic radiations?Electromagnetic radiation contains waves of the electromagnetic field, which propagate through space and carry radiant energy. It includes microwaves, radio waves, infrared, (visible) light, UV, X-rays, and gamma rays.
Electromagnetic radiation posses of electromagnetic waves, which oscillate with the electric and magnetic fields. Electromagnetic waves are created due to periodic changes in the electric field or magnetic field.
Depending on the periodic change that happens and the power produced, different wavelengths of the electromagnetic spectrum are produced. The effects of electromagnetic radiation on chemical compounds and biological organisms depend on the power of the radiation and its frequency.
In order of increasing frequency and decreasing wavelength, these waves are arranged in the electromagnetic spectrum. The transfer of electromagnetic waves from the Sun to the earth, the energy of these waves warms the earth.
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PLS HELP 35 POINTS I WILL GIVE BRAINEST
Answer:
Just count all the different elements like what elemets are in there and you have to identify the number of elemenst
Explanation:
for example H20 and a chemical for example thats two so you identofy which elelments are in there doesnt matter if thered multiple of it all its asking is what id the number of elemts there meaning like one or 2 mayne six different elements
A graduated cylinder initially has 32.5 mL of water in it. After a 75.0 g piece of lead (Pb) is added to the graduated cylinder, the water level rises to the 39.1 mL mark. What is the the volume of the piece of lead.
Answer:
39.1-32.5 and you will find your answer it always like that, you subtract your starting point from your ending point
Explanation:
The volume of the piece of lead is 6.6 mL
From the question given above, the following data were obtained:
Volume of water = 32.5 mLMass of lead (Pb) = 75 gVolume of water + Lead = 39.1 mLVolume of lead =?The volume of the lead can be obtained as follow:
Volume of lead = (Volume of water + Lead) – (Volume of water)
Volume of lead = 39.1 – 32.5
Volume of lead = 6.6 mL
Therefore the volume of the lead is 6.6 mL
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(a) The absorbance of mixture at 400 nm was 0.40.
Using the standard curve, calculate the
concentration of haemoglobin in g/dl for this female
patient.
Answer:
0.1 g/dl
Explanation:
The standard curve is a graph that relates the absorbance at 400 nm with the concentration of haemoglobin in mg/dl. To obtain the concentration from the absorbance value, we enter in the x-axis (absorbance at 400 nm) with the value 0.40 (the line between 0.2 and 0.6), we extrapolate the line to the curve and read the correspondent value on y-axis (concentration in mg/dl): 100 mg/dl.
So, we convert the concentration from mg/dl to g/dl by dividing into 1000:
100 mg/dl x 1 g/1000 mg = 0.1 g/dl
Therefore, the concentration of haemoglobin of the patient is 0.1 g/dl.
Using the VSEPR model, the molecular geometry of the central atom in ClO3- is:_____.a. bent. b. linear. c. trigonal pyramidal. d. trigonal planar. e. tetrahedral.
Answer:
D
Explanation:
it is trigonal planar, because central atom does not have the lone pairs, equal repulsion
The molecular geometry of the central atom in ClO3- will be triangular pyramidal.
What is VSPER model?The geometry of molecular structures can be predicted using the chemical model known as the valence shell electron pair repulsion hypothesis based on the number of electron pairs surrounding the core atoms of the molecules.
Since ClO3- has a steric number of 4 (one unpaired pair as well as three bonded pairs), can infer that its molecular shape is triangular pyramidal. Its electrical form is tetrahedral, as shown by the Lewis structure above.
Therefore, the correct answer will be option (c).
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Write electron configurations for each of the following atoms. Then write the symbol for the most common ion each would form and the electron configuration of that ion.
a) Be
b) CL
c) Se
d) Rb
Answer:
i dont really know this one
Explanation:
Ions can be made by single element or covalently bonded group of elements. The covalently bonded group of elements is called polyatomic ions or polyatomic atoms.
What is Ions?Any species that contain charge whether it is positive charge or negative charge is called ions. The example of polyatomic ions are sulfate, phosphate, nitrate etc.
a)Electronic configuration of Be is 1s² 2s² and the common ion formed by it is Be⁺².
b)Electronic configuration of Cl is [Ne]3S² 3p⁵and the common ion formed by it is Cl⁻.
c)Electronic configuration of Se is [Ar] 3d¹⁰ 4s² 4p⁴ and the common ion formed by it is Se⁻².
d)Electronic configuration of Rb isKr 5s¹ and the common ion formed by it is Rb⁺¹ .
Therefore, Cation is the species that loose electron and attain positive charge while anion is a species which gain electron and attains negative charge
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A patient had for dinner a 3 oz steak, 3 oz salmon, 1 medium apple, and 1 cup of nonfat milk. Using the
chart below, how many total calories did they consume?
Protein
awbohydrate
15
Fal)
0
0
1
126
0
14
22
D
3
4
Food
Apple, 1 medium
Banana, medium
Beel ground, 3oz
Broccoli 304
Carrots, cup
Chicken no skin, 30
Egg, farge
Mik nanta 1 cup
Potato, baked
Salmon 3 02
11
9
2
20
0
3
16
6
10
12
19
10
10
3
23
0
5
16
22
19
Steak 3 0
10
Answer:
1
Explanation:
because there barely eating and there eating protien and healthy foods
When the absolute value of the difference in electronegativity of two adjacent atom in a compound is 1, they are most likely bonded by:____________.
a. nonpolar covalent bond
b. a polar covalent bond
c. ionic bonding
Answer:
A polar covalent bond
Explanation:
When the absolute value of the difference in electronegativity of two bonded atoms is between 0.4 and 1.8 they tend to form polar covalent bonds.
Examine the following electron configuration:
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p1
11) How many total electrons are there?
12) Which element is this?
13) How many electrons are in the fourth energy level of this element?
14) What is the valence electron configuration of this element?
15) How many electrons are in the outermost energy level?
Answer:
The answer to 12 is Indium... you should be able to figure out the rest from there with help from the internet since i've given you the element
Explanation:
I would usually do it but I got a ton of hw
Iodine 131, cesium 137, and strontium 90 are all considered isotopes. What are isotopes?
Answer:
Isotopes are variants of an element, where the number of neutrons is different but its number of protons stay the same.
Explanation:
If the number of protons had changed then it would just be a different element.
Electron number changing simply adds charge to the atom, and doesn't change it or anything.
PLS GIVE BRAINLIEST
Answer:
Isotopes are one of two or more forms of the same chemical element.
Explanation:
Different isotopes of an element have the same number of protons in the nucleus, giving them the same atomic number,but a different number of neutrons giving each element isotope of a different atomic weight.
PLEASE HURRY WILL GIVE BRAINLEST IF ANSWERED CORRECTLY
which separation method would be most successful in separating the components of a homogeneous mixture
screening
evaporation
centrifugation
magnetic separation
Answer:
Evaporation is a technique used to separate out homogeneous mixtures where there is one or more dissolved salts.
Explanation:
Hope this helps :)
Copper coins turn green when exposed to water. What happens to this chemical reaction if the coins are heated?
1.The coins will turn green slower because chemical reactions slow down with higher temperatures
2.The coins will turn green faster because chemical reactions speed up with higher temperatures
3.The coins will turn green at the same rate as before because temperature has no affect on the speed of chemical reactions
4.The coins will not turn green, algae cannot survive in hot temperatures
Answer:
The coins will turn green faster because chemical reaction speed up with higher temperatures
Copper coins turn green when exposed to water because the coins will turn green faster because reaction speeds up with higher temperatures.
What is the rate of the chemical reaction?The rate of a chemical reaction can be defined as the speed at which the products are formed from the reactants. The rate of a reaction gives information about the time frame under which a reaction can be finished.
The rate of reaction can be described as the speed of a chemical reaction at which reactants are transformed into products. Some chemical reactions are generally instantaneous, while some reactions take time to reach the final equilibrium. Pressure increases the concentration of gaseous reactants resulting in an increase in the rate of reaction.
The rate of reaction will increase with an increase in the temperature of the reaction as the reactant molecules get more kinetic energy and increase the number of collisions.
Therefore, copper coins will turn green faster because reactions speed up with higher temperatures.
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What are phytoplankton and what percentage of oxygen do they produce? (ASAP)
Answer:
They are plants also known as plankton and they produce about 80-85% of the world's oxygen.
Explanation: