Answer:
Dry ice is the solid form of carbon dioxide (CO 2), a molecule consisting of a single carbon atom bonded to two oxygen atoms. Dry ice is colorless, odorless, and non-flammable, and can lower the pH of a solution when dissolved in water, forming carbonic acid (H 2 CO 3).
Explanation: i asked my teacher and this was her response.
Evaluate: (12)2 ×102 −6.3 ÷2.1
21.4 A
22 B
9.3 C
75 D HELP PLS
Answer:
answer is 2,445..or B as its noted
New research shows that a red food colouring with an R value of 0.62 (when a particular solvent and temperature are used) could be dangerous to certain people. Samples of food colouring from two different red sweets were collected and the chromatogram bolow was produced. For each of the sweets, state and explain whether or not you would recommend that the sweets are taken off the market based on this research,
It is recommended only for the second type of candy to be taken off the market.
Based on the background information, if a candy shows a 0,62 Rf value in the chromatography it is considered potentially dangerous, and therefore it should be taken off the market.
The Rf value is calculated using the following formula:
Rf = Total distance traveled by a component/ Total distance from the pencil line to the solvent frontNow, let's find out if any of the components has an Rf equal to 0,62.
Note: To determine the distances I measured the image using a ruler and you can do the same, this will not alter the results.
Sample 1Total distance traveled by the component: 6cmTotal distance: 7 cmRf : 6 cm/ 7 cm = 0.852. Sample 2
Total distance traveled by the component: 4.34cmTotal distance: 7 cmRf : 4.34 cm/ 7 cm = 0.62This means sample 2 has the 0.62 Rf value and therefore it needs to be taken off the market.
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Which procedures were followed in this lab to decrease experimental error? Check all that apply.
using only two types of seeds, both from the same source
having one student count every sprout in every quadrat
using adjacent plots of land for both groups
increasing the sample size by combining data from multiple groups
repeating the experiment indoors under growth lights
measuring plant height the same way and at the same time for both groups
Answer:
Basically A, C, D, F
Explanation:
Summarizing the answer
Using only two types of seeds, both from the same source.
What are experimental error?Experimental error refers to the uncertainties or mistakes that can occur during scientific experiments, leading to inaccuracies in the results. These errors can arise due to a variety of reasons, such as human error, instrumental error, environmental factors, and methodological issues. The presence of experimental error can make it difficult to draw accurate conclusions from the data obtained during an experiment.
Scientists use various procedures to reduce experimental error and improve the accuracy and reliability of their results. These procedures can include:
using adjacent plots of land for both groupsincreasing the sample size by combining data from multiple groupsmeasuring plant height the same way and at the same time for both groups.Learn more about experimental error, here:
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help me please i dont understand
Answer:
1. Dissolving powder in milk - Chemical
- It is chemical because the milk has changed on a molecular level
2. Toasting bread - Chemical
- It is chemical because adding heat to the bread cooks it, therefore
changing it on a molecular level
3. Melting cheese - Physical
- It is physical because the physical appearance was the only change
4. Slicing apples or bannanas - Physical
- It is physical because the physical appearance was the only change
5. Frying an egg - Chemical
- It is chemical because new particles were formed
6. Milk souring - Chemical
- It is chemical because it is forming a new product (lactic acid)
Explanation:
Physical Change occurs when the particles of a substance become rearranged, but do not change into different particles.
Chemical change occurs when a new substance is formed. This process is irreversable.
Answer:
give the preson above brainly bc there right
Explanation:
Earth’s layers are determined by their physical properties and chemical composition. In the lesson, you learned about each of Earth’s layers, what the layers are made of, and why they are important to the Earth. In the space below, write about how the atmosphere may be classified. Would it be part of the lithosphere, or a separate layer? Explain your answer.
Answer:
The Atmosphere Is a separate layer And Also could be classified as the Closest layer
Explanation:
How many liters are in 4 moles of a gas at stp?
Answer:
Molar volume at STP can be used to convert from moles to gas volume and from gas volume to moles. The equality of 1 mole = 22.4 L is the basis for the conversion factor.
Explanation:
How many grams of water are needed to absorb 456 J if its temperature goes from 22.7 to 98.3 Celsius?
The mass of water needed to absorb 456 J is 1.44 g
We'll begin by calculating the change in the temperature of the water.
Initial temperature of water (T₁) = 22.7 °C
Final temperature (T₂) = 98.3 °C
Change in temperature (ΔT) =?ΔT = T₂ – T₁
ΔT = 98.3 – 22.7
ΔT = 75.6 °CFinally, we shall determine the mass of the waterHeat absorbed (Q) = 456 J
Change in temperature (ΔT) = 75.6 °C
Specific heat capacity of water (C) = 4.184 J/gºC
Mass of water (M) =?Q = MCΔT
456 = M × 4.184 × 75.6
456 = M × 316.3104
Divide both side by 316.3104
M = 456 / 316.3104
M = 1.44 gTherefore, the mass of the water is 1.44 g
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 Write the chemical compounds and names for the following ionic compounds. Magnesium and phosphorus 
Answer:
Magnesium is Mg.
Phosphorus is P.
The compound of ammonium sulfate consists of two ions. NH4+ and SO42- both of which are polyatomic ions. a molecule of the compound consists of (one, two , or four) NH4+ ions and (one, two, or four) SO42- ions?
Answer:
Blank #1: Polyatomic
Blank #2: 2 (see explanation)
Blank #3: 1 (see explanation)
Explanation
Both the ammonium ion and the sulfate ion contain more than one atom in each ion. The two species are thus polyatomic. The chloride ion , for example, is monoatomic.
Superscripts above formulae of the ions indicate their charge. Each ammonium ion carries a positive one (+1) charge. Each sulfate ion carries a charge of negative two (-2).
Ammonium sulfate is an ionic compound. A sample of this compound contain myriads of ammonium ions and sulfate ions. The ions are packed in three-dimensional lattices. Thus unlike water, ammonium sulfate does not exist as molecules in nature.
Assuming that the second and third blanks refers to a formula unit, rather than a molecule, of ammonium sulfate. The empirical formula of ammonium sulfate gives the minimum whole-number ratio between the two ions in a sample.
Charges shall balance between the two ions. Ammonium ions are of charge +1. Sulfate ions are of charge -2. The sample shall thus contain two ammonium ions for every one sulfate ion.
The empirical formula of ammonium sulfate is therefore .
There are thus two ammonium ions and one sulfate ion in each formula unit of ammonium sulfate.
There are two types of chemical compound one is covalent compound and other is ionic compound, covalent compound formed by sharing of electron and ionic compound formed by complete transfer of electron. Therefore, a molecule of the ammonium sulfate consists of one NH₄⁺ ions and one SO₄²⁻ ions.
What is chemical Compound?Chemical Compound is a combination of molecule, Molecule forms by combination of element and element forms by combination of atoms in fixed proportion.
An ionic compound is a metal and nonmetal combined compound. Ionic compound are very hard. They have high melting and boiling point because of strong ion bond. The compound of ammonium sulfate consists of two ions. NH₄⁺ and SO₄²⁻ both of which are polyatomic ions. A molecule of the ammonium sulfate consists of one NH₄⁺ ions and one SO₄²⁻ ions.
Therefore, a molecule of the ammonium sulfate consists of one NH₄⁺ ions and one SO₄²⁻ ions.
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`Carbon Dioxide and Water are the _______ in a chemical reaction. 2. Reactants are also called the starting _______ in a chemical reaction.: Reactants are also called the starting _______ in a chemical reaction. 3. This type of energy comes from the sun: a This type of energy comes from the sun 4. You get this type of energy from food: b You get this type of energy from food 5. The process by which plants use the sun to produce glucose and oxygen.: The process by which plants use the sun to produce glucose and oxygen. 6. The products of photosynthesis: The products of photosynthesis 7. The location of photosynthesis in plant cells: The location of photosynthesis in plant cells 8. Another name for glucose is: Another name for glucose is 9. Energy is provided by this cell organelle during cellular respiration: Energy is provided by this cell organelle during cellular respiration 10. The largest source of energy on earth comes from the: d The largest source of energy on earth comes from the Column B a.Chloroplast b.Ingredients c.Reactants d.Sun e.Radiant energy f.Sugar g.Chemical energy h.Glucose and Oxygen i.Mitochondria j.Photosynthesis
A student is asked to describe three random
elements found on the periodic table. All three
elements will FOR SURE have which of the two
following characteristics?
A. similar color and texture
B. shininess and value
C. mass and volume
D. similar boiling and freezing points
All three elements in the periodic table will for sure have characteristic of mass and volume.
What is an element?
An element is defined as a substance which cannot be broken down further into any other substance. Each element is made up of its own type of atom which is characteristic of it's own. Due to this reason all elements are different from one another.
Elements can be classified as metals and non-metals. Metals are shiny and conduct electricity and are all solids at room temperature except mercury. Non-metals do not conduct electricity and are mostly gases at room temperature except carbon and sulfur.
The number of protons in the nucleus is the defining property of an element and is related to the atomic number.All atoms with same atomic number are atoms of same element.
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Write the chemical formulas and names for the following ionic compounds. Barium and phosphate 
Barium is Ba. Atomic no. 56 and atomic mass =137.3.
Phosphate is naturally occurring form of phosphorus. Phosphate is P. Atomin no. 15 and atomic mass =31.0.
How many moles of AgNO3 must react to form 0. 854 mol Ag? mol AgNO3.
The moles of silver nitrate required to form 0.854 mol silver ion has been 0.854 mol.
The balanced chemical equation for the dissolution of silver nitrate has been:
[tex]\rm AgNO_3\;\rightarrow\;Ag^+\;+\;NO_3^-[/tex]
The aqueous solution of silver nitrate has been dissociated into the constituent silver and nitrate ions.
In a balanced chemical equation, the coefficient has been equivalent to the moles of each reactant forming the moles of product.
From, the balanced equation,
[tex]\rm 1\;mol\;AgNO_3=1\;mol\;Ag[/tex]
The given moles of Silver has been 0.854 mol. Thus, the moles of silver nitrate required has been given as:
[tex]\rm 1\;mol\;Ag^+=1\;mol\;AgNO_3\\0.854\;mol\;Ag^+=0.854\;\times\;1\;mol\;AgNO_3\\0.854\;mol\;Ag^+=0.854\;mol\;AgNO_3[/tex]
The moles of silver nitrate required to form 0.854 mol silver ion has been 0.854 mol.
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in which time period did the first animals that could live both in water and on land appear
Which of the following is not an ingredient for photosynthesis?
A. Oxygen
B. Carbon dioxide
C. Light energy
D. Vinegar
Answer:
d
Explanation:
......................
Answer:
D. vinegar
Explanation:
Hope this helps you!!
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How do you break down an element?
Answer:
elements cannot be break downHow do covalent compounds differ from ionic compounds?
Answer:
1. Ionic bonds result from transfer of electrons, but covalent bonds are formed by sharing.
2. Ions are arranged in a three-dimensional array (like crystals). Covalently bonded substances exist as discrete molecular units.
3. Ionic compounds often dissociate into ions in solution, but covalently bonded molecules retain their molecular identity in solution.
Hope this helps :)
A calcium atom has 20 protons, 20 electrons, and 20 neutrons. When calcium forms a positive two ion it's new composition is
Answer:
40
Explanation:
I'm not sure
Elements join together to form_____.
Answer:
compounds
Explanation:
When a hurricane approaches land, people living directly on the
coast should always evacuate when told to do so by authorities.
Answer:
True
Explanation:
When a hurricane is dangerous enough that authorities say to evacuate, you should for your own safety.
2. Which substance will form a solution with water? (Select all that app
string
sand
sugar
salt
Answer:
sugar and salt, as they can dissolve in water. Sugar and salt have a high solubility in water. So, sugar and salt can form a solution with water.
Explanation:
I need help, plz help me with this problem
Answer:
It's b
Explanation:
I had the same exact question
what is the chemical formula of tetraphosphorus heptasulfide?
Answer: P4S7
Explanation:
How do you prepare 500ml of 1.77M H2SO4 solution from an 18.0M H2SO4 Stock solution
Answer:
Take 49.2-ml of 18.0 M H2SO4 stock solution and pour it into a 500-ml volumetric flask. Fill to the 500-ml line with distilled water to make 1.77M H2SO4 solution.
Explanation:
use the formula M1V1=M2V2
volume must be in liters(L)
[tex](1.77)(500 \times {10}^{ - 3} ) = (18)v2 \\ 0.885 = 18v2 \\ v2 = \frac{0.885}{18} \\ v2 = 0.04916[/tex]
0.04916L × 1000 = 49.16 ml = 49.2 ml
Which of the following statement is correct regarding motors and generator?
Answer:
A. Motors and generators are opposite processes
Explanation:
B, C, and D are wrong because, the term electrical generator is used to describe a range of devices that convert mechanical energy into electricity. A motor converts electrical energy into mechanical, which is the opposite process to the electrical generator.
what is mass tbh pls he;p
Answer:
how much matter is in an object
Explanation:
Based on the graph, what is the approximate half-life of the reaction shown below
Answer: 2.1 minutes
Explanation: Based on the graph, what is the approximate half-life of the reaction shown below
Why is the molecule not an example of a cis stereoisomer
Answer:
Because in order to have cis or trans configuration both carbon of alkene need to have a hydrogen
3. Explain why the statement "electrons are always located close to the nucleus of an atom" is not really accurate,
Answer:
Electrons are stored in different electron shells with the nucleus in the center. Depending on the size of the element, the electrons may need more shells, making the electrons further away from the nucleus.
Explanation:
Atoms contains nucleus in its center and electron that revolve around the atom in fixed orbit. the statement "electrons are always located close to the nucleus of an atom" is not really accurate.
What is atom?Atom is the smallest particle of any element, molecule or compound. Atom can not be further divided.
In the nucleus, proton and neutron are present. Electron has -1 charge while proton has +1 charge.
Electrons always move in fixed orbit around the nucleus with a particular force. Electrons may or may not be close to the nucleus. Depending on the size of the element, the electrons may need more shells, making the electrons further away from the nucleus.
Therefore, the statement "electrons are always located close to the nucleus of an atom" is not really accurate.
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A diprotic acid (H2X) titrated with a solution of NaOH for 25 ml of the acid 87.42 ml of a 1.95 M solution of NaOH was required to reach the equivalent point, the concentration of the diprotic acid equals
0.14
6.8
3.4
0.29
The concentration of the diprotic acid equals 3.4 M
We'll begin by writing the balanced equation for the reaction.
H₂X + 2NaOH —> Na₂X + 2H₂O
From the balanced equation above,
The mole ratio of the acid, H₂X (nA) = 1The mole ratio of the base, NaOH (nB) = 2From the question given above, the following data were obtained:
Volume of acid, H₂X (Va) = 25 mLVolume of base, NaOH (Vb) = 87.42 mLMolarity of base, Ca(OH)₂ (Mb) = 1.95 MMolarity of acid, H₂X (Ma) =?MaVa / MbVb = nA/nB
(Ma × 25) / (1.95 × 87.42) = 1/2
(Ma × 25) / 170.469 = 1/2
Cross multiply
Ma × 25 × 2 = 170.469
Ma × 50 = 170.469
Divide both side by 50
Ma = 170.469 / 50
Ma = 3.4 M
Therefore, the concentration of the acid, H₂X is 3.4 M
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