The following are the correct decisions;
1) Chemical property
2) Physical property
3) Chemical property
The question is incomplete, the complete question is;
Experiments were done on a certain pure substance X to determine some of its properties. There's a description of each experiment in the table below. In each case, decide whether the property measured was a chemical or physical property of X, if you can. If you don't have enough information to decide, choose can't decide in the third column. property experiment physical or chemical? Х O physical 0 A sample of solid X is carefully weighed and put inside a vented flask. The flask is heated until oxygen gas starts being produced. After no more oxygen gas is produced, the contents of the flask are removed and weighed, and from the decrease in weight the value of O may be calculated. O chemical O (can't decide) O physical V A sample of X is melted and put into a reservoir from which a very thin tube leads down. The rate at which X flows out of the tube is measured, and from this rate the value of V may be calculated. chemical (can't decide) O physical Q A sample of solid X is carefully weighed and put inside a sealed flask. Pure hydrogen gas is added to the flask, and the mixture heated until the hydrogen starts being consumed. After hydrogen stops being consumed, the contents of the flask are removed and weighed, and from the increase in weight the value of may be calculated. O chemical O (can't decide)
A chemical property is one in which atoms of a substances are rearranged in the process. In the first case, the substance was heated and oxygen was produced. This is a decomposition reaction hence it is a chemical property that is being measured.
In the second case, the molten substance is made to flow and the flow rate is measured. The flow rate of a substance is a physical property.
In the third case, hydrogen combines with an element in the flask. This is a chemical property.
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Calculate the number of kilograms of sodium fluoride needed per year for a city of 100,000 people if the daily consumption of water per person is 150.0 gallons.
Fluoridation is the process of adding fluorine to drinking water to avoid tooth decay.
The question is incomplete; the complete question is;
Fluoridation is the process of adding fluorine compounds to drinking water to help fight tooth decay. A concentration of 1 ppm of fluorine is sufficient for the purpose. (1 ppm means one part per million, or 1 g of fluorine per 1 million g of water.) The compound normally chosen for fluoridation is sodium fluoride, which is also added to some toothpastes. Calculate the quantity of sodium fluoride in kilograms needed per year for a city of 50,000 people if the daily consumption of water per person is 150 gallons.
(Sodium fluoride is 45.0 percent fluorine by mass. 1 gallon = 3.79 L; 1 year = 365 days; 1 ton = 2000 lb; I lb = 453.6 g; density of water = 1.0 g/mL.)
The quantity of sodium fluoride in kilograms needed per year for a city of 50,000 people if the daily consumption of water per person is 150 gallons is [tex]9.32 * 10^9 Kg[/tex].
From the question, we know that;
Daily consumption of water per person = 150 gallons.
Population of the city = 100,000 people
Total daily city consumption =[tex]100,000 * 150 gallons = 15 * 10^6 gallons[/tex]
Annual water consumption = [tex]15 * 10^6 gallons * 365 = 5.475 * 10^9 gallons[/tex]
1 gallon = 3.785 L = 3.785 kg
[tex]5.475 * 10^9 gallons = 5.475 * 10^9 gallons * 3.785 kg/ 1 gallon = 2.1 * 10^10 Kg[/tex]
Since sodium fluoride accounts for 45% by mass of water
Mass of sodium fluoride= [tex]0.45 * 2.1 * 10^10 Kg= 9.32 * 10^9 Kg[/tex]
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6. Convert a measurement of 18 cm to its equivalent in m.
7.
Convert a measurement of 75 mL to its equivalent in L.
HELPP?!???!!
Answer:
0.18m
0.075L
Explanation:
1m = 100cm
18cm = 18/100 = 0.18m
1L = 1000mL
75mL = 75/1000 = 0.075L
If my answer is incorrect, pls correct me!
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Perform each calculation to the correct number of significant figures.
(a) 89.3 * 77.0 * 0.08
(b) (5.01 * 105) , (7.8 * 102) (c) 4.005 * 74 * 0.007
(d) 453 , 2.031
Answer:B
Explanation:
Identify all the signs of a chemical change in the description below:
A clear liquid is placed in a beaker and heated. As the liquid is heated, bubbles form and, gradually, the liquid decreases in the container.
Answer:
When a substance undergoes changes in its chemical composition or combines with another substance to form a new substance is referred to as chemical change. In contrast, physical change is defined as the change in appearance or state of matter and not the chemical composition of the substance.
Explanation:
When a clear liquid is boiled or heated, the kinetic energy of the molecules increases, and the evaporation of the liquid takes place faster. For example, evaporation is a type of physical change, in which the liquid is heated to form bubbles or vapors. These vapors rise in the air and decrease the volume of the liquid. In this process, the liquid has only changed its state of matter (liquid to gas) and not the chemical composition. Thus, there is no chemical change taking place in the heating of water and only physical change is taking place.
Select all the correct answers.
What are the characteristics of prokaryotes?
A prokaryote lacks a well-defined nucleus.
A prokaryote cannot perform basic life functions.
A prokaryote lacks cell organelles.
A prokaryote is larger than a eukaryote.
eu vou colocar V(verdadeiro) F (falso)
1:F
2:F
3: V
4:F
explicação:
1 procariontes não apresentam núcleo
2 eles podem sim caso contrário os seres procariontes não sobreviveriam
3 ele possui organelas celulares
4 as células eucariontes são maiores e mais complexas.
CONCLUSÃO: a resposta certa é a 3
Find the volume of 1760 grams of copper
Answer:
(1760 ÷ 64) x 24.4 =671dm^3
Why do other elements need to bond with one another?
Answer:
Atoms form chemical bonds to make their outer electron shells more stable. The type of chemical bond maximizes the stability of the atoms that form it.
Answer:
In order for that element to gain stability
what is the oxidation number of chloride ion HClO ?
The oxidation state of Cl is +1
Einstein also said that gravity can affect not just mass but...
A.nothing else, just mass.
B.light waves or energy
C.everything.
Answer:
B. Light waves or energy
Explanation:
Einstein argued that gravity isn't a force at all. He described it as a curvature of time and space caused by mass and energy.
PLZ MARK ME BRAINLIEST.Which of the following are exact numbers? (Check all that apply.)
1000 meters in one kilometer.
The diameter of a coin, 10.2756mm (millimeters)
A dozen eggs.
16 ounces in 1 pound.
The length of a pen, 12mm (millimeters)
For the given options we found that the following are examples of exact numbers:
1000 meters in one kilometer is an exact numberA dozen eggs is an exact number. 16 ounces in 1 pound is an exact number.To find which of the given examples are exact numbers, we need to recall its definition. In simple words, an exact number is a number that can be counted without uncertainties, usually is an integer one.
A number that is determined with uncertainties with a finite number of significant digits or thought an instrument is not an exact number (is a measured one).
Now, let's evaluate each option.
a) 1000 meters in one kilometer
This is an exact number because we know for certain that in 1 kilometer there are 1000 meters. All the conversion of units like meters to kilometers, grams to kilograms are examples of exact numbers.
b) The diameter of a coin, 10.2756 mm
This is not an exact number, because the diameter found has a finite number of significant digits, which means that the measurement has an uncertainty in the final decimal position. Also, this diameter was found with an instrument.
c) A dozen eggs
A dozen is a number that can be counted with certainty, so it is an exact number.
d) 16 ounces in 1 pound
This is like example "a". Since we know for sure that in 1 pound we have 16 ounces, this is an exact number.
e) The length of a pen, 12 mm
Although the number 12 mm is an integer, this is not an exact number because this dimension was measured. We do not know for sure that the dimension of a pencil is 12 mm, we can not count it.
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Does anyone know the name of Platinum +1 and Sulfur? Like the compound name?
How is scientific observation done properly and safely using laboratory equipment?
6.Observe the equation below 2 Fe2O3(s) + CO(g) Fe(s) + CO2(g)
i) Balance the equation
Answer:
the given equation is
Fe2o3+co-- Fe+co2
Balanced chemical equation is
Fe2o3 + 3co-- 2Fe+3co2
4. Select the measurement that is consistent with the uncertainty of each instrument.
(a) METRIC RULER A: 10 cm, 10.0 cm, 10.00 cm
(b) METRIC RULER B: 10 cm, 10.0 cm, 10.00 cm
(c) decigram balance: 10.0 g, 10.00 g, 10.000 g
(d) centigram balance: 10.0 g, 10.00 g, 10.000 g
(e) milligram balance: 10.0 g, 10.00 g, 10.000 g
(f) graduated cylinder: 10 mL, 10.0 mL, 10.00 mL
(g) Celsius thermometer: 10 °C, 10.0 °C, 10.00 °C
The correct measurements has an uncertainty of ±0.01.
What is the metric system?The metric system of measurement is a system of measurement that makes use of the meter, litre and gram as units. With every measurement, there is a level of uncertainty.
The uncertainly that goes with each measurement usually lies between ±0.01. Hence the correct measurements has an uncertainty of ±0.01.
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Help please! I’m not sure if metal b has higher density then a & I don’t know the other questions without that information.
Answer:
How would you set this up?
Explanation:
What is photosynthesis ?
[tex] \huge \boxed{\mathfrak{Question} \downarrow}[/tex]
What's photosynthesis?[tex] \large \boxed{\mathfrak{Answer \: with \: Explanation} \downarrow}[/tex]
Photosynthesis is the process in which green plants derive their food (nutrients and water) through the capturing of light energy (sunlight) and using it to convert carbon dioxide (CO2) and water (H2O) into oxygen (O2) and other substances (compounds) that are rich in energy. Chlorophyll a green pigment present in plants is used in this process.
__________________
Formula ⟶ [tex]\boxed{\bf\:6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2} [/tex]
__________________
So, the products of photosynthesis are [tex]\large\boxed{\boxed{\bf\:C_6H_{12}O_6 + 6O_2}}[/tex]
Carry out the following conversions. Report your answers to the correct number of significant
figures.
(a) 75 cm to ft
ft
(b) 0.668 kg to lb
Ib
(e) 0.549 uL to qt
* 10-qt
(d) 9,991 mm to km
9.991 x 10 (select)
km
(e) 313 nm to mm
3.13 x 10 (select)
mm
(1) 7 ft to cm
* 102 cm
We want to perform some changes of units, such that the number of significant figures (the ones different than zero) does not change.
a) 75 cm to ft
We know that:
1ft = 30.48cm
1 = (1ft)/(30.48cm)
Now, remember that if we multiply a quantity by one we do not affect the quantity, so we can write:
75cm = 75cm*(1ft)/(30.48cm) = 2.5 ft
b) 0.668 kg to lb
we know that:
1kg = 2.20462 lb
then:
1 = (2.20462 lb)/(1kg)
0.668 kg = 0.668 kg*(2.20462 lb)/(1kg) = 1.47 lb
c) 0.549 uL to qt
We know that:
1 uL = 3.437*10^-9 qt
1 = (3.437*10^-9 qt)/(1 uL)
Then:
0.549 uL = 0.549 uL*(3.437*10^-9 qt)/(1 uL) = 1.91*10^-9 qt
d) 9.991 mm to km
we know that:
1mm = 1*10^-6 km
then:
1 = (1*10^-6 km)/(1mm)
So we can rewrite:
9.991 mm = 9.991 mm*(1*10^-6 km)/(1mm) = 9.991*10^-6 km
e) 313 nm to mm
We have:
1nm = 1*10^-6 mm
1 = ( 1*10^-6 mm)/(1 nm)
Then:
313 nm*( 1*10^-6 mm)/(1 nm) = 3.13*10^-4 mm
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Sublimation cannot be used to separate a mixture of salt and sand.Give reason.
Answer:
because salt cannot be changed into gas by heating.
Answer:
Sublimation is the transition of a substance directly from the solid to the gas phase, without passing through the intermediate liquid phase. Explanation: sand and salt can not be separated through the method of sublimation because none of the two can show sublimation(even when heated).
Explanation:
What is an atomic number
Answer:
the number of protons in the nucleus of an atom, which is characteristic of a chemical element and determines its place on the periodic table
Al saltar una persona del Bungee se observa que las cuerdas con las que se sujeta muestran un
grado de estiramiento por el peso y la velocidad que alcanza, una vez que ya no hay movimiento,
las cuerdas retoman su forma original. ¿Qué propiedad física se presenta?
La propiedad física es la elasticidad.
La elasticidad es la capacidad de un material para extenderse cuando está bajo la acción de una fuerza de estiramiento y volver a su forma original cuando se elimina la fuerza de estiramiento.
Cuando la persona que salta sostiene el bungee, se encuentra que se estira y vuelve a su forma original cuando no hay más movimiento. El bungee puede considerarse elástico.
Este es un ejemplo de la propiedad física llamada elasticidad.
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50 POINTS!!!! What is the approximate amount of the leftover reactant?
O 8.2 g of sulfuric acid
O 9.8 g of sulfuric acid
0 11.43 g of aluminum hydroxide
O 13.76 g of aluminum hydroxide
Answers: The answer is A
Explanation:
correct me if I'm wrong
Which element does not have the same number of electrons in its outermost shell as the other elements in its group?(1 point)
hydrogen (H)
boron (B)
helium (He)
bromine (Br)
Answer:
Helium
Explanation:
The element that does not have the same number of electrons in its outermost shell as the other elements in its group is helium. The correct option is C.
What is helium?Helium is a gas and the second element of the periodic table. It has an atomic number of 2. It is a colorless, odorless, and non-toxic gas. Furthermore, it is the lightest gas, and it is used in filling in the tires of airplanes and balloons.
The group in which helium is present in group 18. It contains 6 elements. Helium is the first element. All element in the periodic table has eight electrons in their last shell. But only helium has 2 electrons in its outer valence. So, helium is different from other elements present in its group.
Thus, the correct option is C. helium (He).
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how to find the number of electrons not in a neutral atoms ?
Answer:
To determine how many total electrons there are, add the amount of charge to the atomic number
Explanation:
For example, N3- has a -3 charge which means it has 3 more electrons than a neutral nitrogen atom. Nitrogen's atomic number is 7, therefore this ion has 10 electrons.
Weight is the measure of what
Answer:
weight is the measure of force put onto an object
like if you put a heavier object on something elastic, it would go lower because weight creates force and friction
(giving brainlist! What should a simplified model of a large molecule like glucose show?
Glucose is a carbohydrate and monosaccharide sugar molecule that is the energy source for organisms. The simplified model of a glucose molecule will show six carbon atoms, six oxygen atoms, and twelve hydrogen atoms.
What is glucose?Glucose is one of the monosaccharide sugar that is the most abundant energy source with a molecular formula of C₆H₁₂O₆. It consists of carbon, hydrogen, and oxygen atoms with a molecular mass of 180.156 g/mol.
It is a sugar-containing aldehydic group with a six-carbon making it aldohexoses. It is found in honey and fruits that are the source of the energy and regulates metabolic and cellular reactions.
Therefore, the molecular structure of glucose contains six carbon, twelve hydrogens, and six oxygen atoms.
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Help me:what helium
and what use
Answer:
the chemical element of atomic number 2, an inert gas which is the lightest member of the noble gas series.
Explanation:
Because it is very unreactive, helium is used to provide an inert protective atmosphere for making fibre optics and semiconductors, and for arc welding. Helium is also used to detect leaks, such as in car air-conditioning systems, and because it diffuses quickly it is used to inflate car airbags after impact.
Would overheating be a stimulus or a
response?
Stimulus
Response
Answer:
stimulus response
Explanation:
its stimulus response
Someone help answer this for me tysm
Answer:
Energy, Kinetic, Potential
Explanation:
Kinetic and Potential is energy
Kinetic is energy in motion and Potential is stored motion.
What is the mass of 4.99×1021 platinum atoms?
Answer:
[tex]\boxed {\boxed {\sf 1.62 \ g \ Pt}}[/tex]
Explanation:
We are asked to find the mass of a number of platinum (Pt) atoms.
1. Convert Atoms to MolesFirst, we convert atoms to moles using Avogadro's Number or 6.022 × 10²³. This is the number of particles (atoms, molecules, formula units, etc.) in 1 mole of a substance. In this case, the particles are platinum atoms.
We will convert using dimensional analysis so we set up a ratio using the information we know (6.022 × 10²³ platinum atoms in 1 mole of platinum).
[tex]\frac {6.022 \times 10^{23} \ atoms \ Pt}{ 1 \ mol \ Pt}[/tex]
We are converting 4.99 ×10²¹ atoms of Pt to moles of Pt, so we multiply by this value.
[tex]4.99 \times 10^{21} \ atoms \ Pt *\frac {6.022 \times 10^{23} \ atoms \ Pt}{ 1 \ mol \ Pt}[/tex]
Flip the ratio so the units of atoms of platinum cancel.
[tex]4.99 \times 10^{21} \ atoms \ Pt *\frac { 1 \ mol \ Pt}{6.022 \times 10^{23} \ atoms \ Pt}[/tex]
[tex]4.99 \times 10^{21} *\frac { 1 \ mol \ Pt}{6.022 \times 10^{23}}[/tex]
[tex]\frac { 4.99 \times 10^{21}}{6.022 \times 10^{23}} \ mol \ Pt[/tex]
Divide.
[tex]0.008286283627 \ mol \ Pt[/tex]
2. Convert Moles to GramsNext, we convert moles to grams using the molar mass. This is the mass of 1 mole of a substance. This is found on the Periodic Table because it is equivalent to the atomic mass, but the units are grams per mole instead of atomic mass units. Look up platinum's molar mass.
Pt: 195.08 g/molSet up another ratio using this new information (195.08 grams of Pt in 1 mole of Pt).
[tex]\frac {195.08 \ g \ Pt}{ 1 \ mol \ Pt}[/tex]
Multiply by the number of moles we just calculated.
[tex]0.008286283627 \ mol \ Pt*\frac {195.08 \ g \ Pt}{ 1 \ mol \ Pt}[/tex]
The units of moles of platinum cancel.
[tex]0.008286283627*\frac {195.08 \ g \ Pt}{ 1 }[/tex]
[tex]0.008286283627* {195.08 \ g \ Pt}[/tex]
[tex]1.61648821\ g \ Pt[/tex]
3. RoundThe original measurement of atoms ( 4.99 ×10²¹ ) has 3 significant figures, so our answer must have the same. For the number we found, that is the hundredth place. The 6 in the thousandth place tells us to round the 1 up to a 2.
[tex]1.62 \ g \ Pt[/tex]
There are approximately 1.62 grams of platinum in 4.99 ×10²¹ atoms of platinum.
is Isoheptenes hazardous when wet
Answer:
yes it is dangerous
Explanation:
Water reactive substances are dangerous when wet because they undergo a chemical reaction with water.
