The diagram below shows a helium atom and its
corresponding symbol.
Symbol: 4
HE
2
What does the top number in the symbol tell you
about the atom?
This is the mass number A. It shows the number of nucleons (neutrons and protons in the nucleus). It is made up of the atomic number Z and the neutron number N:
A = Z + N
Using the example of helium:
Helium has a mass number A of 4 and the atomic number Z 2, so the atom has 2 neutrons in its nucleus.
A = Z + N
4 = 2 + 2
Wood is mainly cellulose, a polymer produced by plants. One use of wood is as a fuel in campfires, fireplaces, and wood furnaces. The molecules of cellulose are tong chains of repeating units. Each unit of the chain can be represented as C.HOs. The balanced equation below represents a reaction that occurs when C.HOs is burned in air.
C6H1005 + 0₂ → CO₂ + H₂O + heat
5. Balance the chemical equation using the smallest whole number coefficient.
Answer:
C6 H10 O5+ 6O2-----> 6CO2+5H2O+heat
Explanation:
There are 6 carbon atoms in reactants to balance you put coefficient 6.
This makes the oxygen in CO2 12 so to balance put 6 in oxygen in reactants.
There are 10 hydrogen atoms in reactants to balance you put 5 in front of H2O in products.
If u recheck: 6 C atoms in reactants, 6 C atoms in products.
10 H atoms in reactants, 10 H atoms in products.
17 O atoms in reactants, 17 O atoms in products.
Classify the following materials as solid, liquid, or gas at room temperature: milk, helium , granite , oxygen , steel , and gasoline
Answer:
milk liquid
helium gas
granite solid
oxygen gas
steel solid
gasoline liquid
Answer: Milk is liquid. Helium is gas. Granite is solid. Oxygen is gas. Steel is solid. Gasoline is liquid.
Explanation:
The atomic mass unit is equivalent to 1 of the mass of a neutral atom of which element? (1 point)
O carbon
o hydrogen
O gold
O oxygen
The atomic mass unit is equivalent to 1 of the mass of a neutral atom of carbon.
What is Atomic Mass Unit?It is defined as one out of twelve parts of the mass of the neutral atom of the most abundant isotope of carbon, that is, carbon 12.
By this definition, it is obvious that the atomic mass unit of elements is measured with respect to the mass of a neutral atom of carbon 12 - not hydrogen, gold, or oxygen.
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60 points and brainliest! please help me i will appreciate it!
1. particles of an atom.
2. what is a neutron
Answer:
1. The three parts of an atom are:
ProtonsNeutronsElectrons2. A neutron is a particle of an atom with a neutral charge.
Hope this helps!
NEED HELP ASAP
During an experiment, ice and water were placed in a perfectly insulated thermos flask at 0 °C. Describe this system when it phase reaches equilibrium.
By the time thermal equilibrium is attained in the system, ice is completely converted to water.
What is tehrmal equilibrium?Thermal equilibrium is a situation in which two substances are exactly at the same temperature. That is. Heat is no longer flowing beween the bodies.
Recall that an insulated thermos flask implies that heat does not eneter or leave the system. Heat will flow from the water to the ice untill the both attains the same temperature and the ice is completely converted to water.
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Using the table below, provide a reason as to why the energy needed to heat the
Sample A is significantly less than Sample B.
Mass of
Water
Change
in Temp.
Energy
Needed
Sample A 50 grams
15 °C
3138
joules
Sample B 50 grams
15 °C
19788
joules
Answer:
Explanation:
Both Sample A and B have the same mass (5g) and same temperature change (15°C). What is not said and may explain the difference in energy needed are their initial states and temperature.
For example Sample B may be liquid water at 90°C. Heating it up to 105°C will require additional energy to go from liquid to gas state. If Sample A is water vapor at 105°C at first, it has a lower specific heat and heating it up to 120°C does not involve a state change. So the eneregy needed is less.
How many kiloliters are in 602,000,000 microliters?
Answer:
0.602
Explanation:
is your answer good sir
Answer:
The correct answer is 0.602 .Mark BRAINLIEST
Thank you ☺️☺️
What are two costs of using tides for energy?
Answer:
Answer: According to 2019 figures from the US Department of Energy, the average commercial tidal energy project costs as much as $280 per megawatt hour. Wind energy, by comparison, currently costs roughly $20 per megawatt hour and is "one of the lowest-priced energy sources available today," according to the agency.
Explanation:
Answer:
The two cost of using tides for energy is solor and wind.
help this question im kinda stuck on
Answer:
Explanation:
i think it is the last one. hope it is correct
Which of Dalton's postulates required revision?
Answer:
Dalton's 5 postulates
All matter consists of indivisible particles called atoms.
Atoms of the same element are similar in shape and mass, but differ from the atoms of other elements.
Atoms cannot be created or destroyed.
Atoms of different elements may combine with each other in a fixed, simple, whole number ratios to form compound atoms.
Explanation:
Which is heavier, 0.5 moles of Mg or 5 moles of H2?
Answer:
hydrogen
Explanation:
b/c H= 5×2=10
Mg=0.5×1 =1
What are some characteristics of Tundra Biomes ?
Answer:
Characteristics of tundra include:
Extremely cold climate.
Low biotic diversity.
Simple vegetation structure.
Limitation of drainage.
Short season of growth and reproduction.
Energy and nutrients in the form of dead organic material.
Large population oscillations.
Explanation:
Ice cubes are placed on a table in a warm room. What happens to the ice particles?
1. The particles become larger.
2. The particles move faster.
3. The particles change color.
4. The colors change shape.
B
Explanation:
I rember when I learned this in 3rd grade
How does rapidly increasing volume of the gas without a change in the moles or temperature affect the pressure in a gas container
Answer:
pressure decreases
Explanation:
increasing volume means increase the room
imagine tennis balls bouncing around in a room
if the size of the room increases the tennis balls hit the walls less often
ohemfsuedu
Physician Barry Marshall infected which test subject to investigate the role of Helicobacter pylori in peptic ulcers?
Cats
Dogs
Guinea pigs
Himself
None of the above
chemistry balance equations C2H +O2=CO2+H2O
Invalid equation.
..............
5. A flame test can be used to identify an unknown element. A student reacts two chemicals and decides to perform a flame test on the resulting product. If the product gives off a magenta hue when in flames, which element is likely to be present? Use your lab data to help determine the identity of this element.
Answer:
The element that is likely to be present is LITHIUM.
Explanation: ABOUT FLAME TEST
An analytical chemistry method used to help identify metal ions is the flame test. It can not be used to classify all metals, although it is a useful qualitative research test and a lot of fun to perform, since not all metal ions emit flame colors. Some metal ions also display colors similar to each other, making it difficult to tell them apart. However, for the detection of various metals and metalloids, the test is still useful.
One downside of the flame test is that the light color that is detected depends very much on the flame's chemical composition (the fuel that is being burned). This makes it difficult to match colors with a chart that has a high level of trust.
The bead test or blister test, in which a bead of salt is coated with the sample and then heated with a Bunsen burner flame, is an alternative to the flame test. Because more samples stick to the bead than to a simple wire loop, this test is slightly more accurate and Since most Bunsen burners, which appear to burn with a clean, blue flame, are linked to natural gas.
ABOUT LITHIUM ELELMENT -:It's metal, but it's soft enough to cut with a knife .It is so light that water can float on it. It is hard to put out lithium fires. Lithium, along with hydrogen and helium, was one of the three elements that the Big Bang produced in vast amounts.
Hence , we identifies the element in flame test by the color produces that is magenta or pink-red which gives the element Lithium . Therefore , the correct answer is lithium.
A quantity of gas has a volume of 250 L, at 290 K and 303.98 kPa of pressure. What volume must the gas be for the gas to be at 273 K and at 101.33 kPa?
The new volume of the gas at a temperature of 273 K and at pressure of 101.33 KPa is 706.01 L
Data obtained from the question Initial volume (V₁) = 250 LInitial temperature (T₁) = 290 KInitial pressure (P₁) = 303.98 KPaNew temperature (T₂) = 273 KNew pressure (P₂) = 101.33 KPaNew Volume (V₂) =? How to determine the new volumeThe new volume of the gas can be obtained by using the combined gas equation as illustrated below:
P₁V₁ / T₁ = P₂V₂ / T₂
(303.98 × 250) / 290 = (101.33 × V₂) / 273
Cross multiply
290 × 101.33 × V₂ = 303.98 × 250 × 273
Divide both side by 290 × 101.33
V₂ = (303.98 × 250 × 273) / (290 × 101.33)
V₂ = 706.01 L
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Convert the following number of moles of the chemical into its corresponding mass in grams
1. 2.360 moles of lead (II) oxide
Convert the following masses into their corresponding number of moles.
2. 23.5 g of sodium chloride
3. 0.778 g of sodium cyanide
Convert the following number of moles into their corresponding number of particles.
4. 0.0455 moles of hydrochloric acid
[tex]mass = number \: of \: moles \times molar \: mass[/tex]
1)[tex]m = 2.36(223.2) = 526.752 \: grams[/tex]
2)[tex]n = \frac{mass}{molar \: mass} = \frac{23.5}{58.4} = 0.40239 \: moles[/tex]
3)[tex]n = \frac{0.778}{49} = 0.0158775 \: moles[/tex]
4)[tex]n = \frac{number \: of \: particles}{avogadros \: constant} [/tex]
[tex]n \: o \: p = 0.0455 \times 6.02 \times 10 {}^{23} = 2.7391 \times 10 {}^{22} particles[/tex]
Mass in grams of 2.360 moles of lead (II) oxide is 0.0105.
What is mole concept?Avogadro's number is the number of units in one mole of any substance and equals to 6.02214076 × 10²³. The units can be electrons, atoms, ions, or molecules.
No. of moles is defined as a particular no. of particles that we can calculate with the help of Avogadro’s number.
Mass of a particular product is also find out by stoichiometry of a reaction as per the no. of mole given in the reaction.
Given, No. of moles of lead oxide = 2.360 grams
No. of moles = Mass of compound ÷ Molar mass of compound
No. of moles = 2.36 ÷ 223.2
No. of moles = 0.0105
Therefore, Mass in grams of 2.360 moles of lead (II) oxide is 0.0105.
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True or false for the following questions?
Answer:
T
F
T
Explanation:
hope it helps! sorry for no explanation
The molecular weight of water, H2O is 18.02 g/mol. How many moles of water are in 24.3 g of water?
Answer:
1.35moles
Explanation:
mm=18.02gmol⁻¹ mass=24.3g
mole=mass/mm
mole=24.3/18.02
mole=1.35moles
Answer:
The answer is 1.35 molesExplanation:
To find the number of moles given the molecular weight and mass we use the formula
[tex]n = \frac{M}{m} \\ [/tex]
where
n is the number of moles
M is the molar mass
m is the mass of the substance
From the question
m = 24.3 g
M = 18.02 g/mol
We have
[tex]n = \frac{24.3}{18.02} \\ = 1.348501664...[/tex]
We have the final answer as
1.35 molesHope this helps you
Three years after the first Moon landing, which two countries linked up spacecrafts to famously shake hands?
A. China and Russia
B. the United States and the Soviet Union
C. China and the United States
D. Russia and the Soviet Union
Answer: B. the United States and the Soviet Union
Explanation:
The unit of area is derived unit why
Answer:
A derived unit is gained by adding two or more base quantities and in this case area is obtained by adding two more base quantities.
Quantity :Area = length(base quantity) × breadth(base quantity)
Derived unit of area = m(SI base unit ) × m(SI base unit) = m²
WILL GIVE BRAINLIEST AND POINTS
What is a synonym and antonym for Magnetic Field Line?
What is a synonym and antonym for Magnetic Pole?
Answer:
Magnetic field and Magnetic Pole
Explanation:
Synomyns for magnetic field is magnetic flux.
Synonyms for magnetic pole is magnetic rod
Antonyms for magnetic field is magnetic pole
Antonyms for magnetic pole is magnetic voltaic cell
The percent yield of a chemical reaction is valuable to many industries. Low percent yields can result in the loss of large amounts of money. Which of the following would likely increase the percent yield of a reaction? Check all that apply. Using accurate measurements using pure chemicals performing the reaction under the most ideal conditions adding water to the experiment.
Using accurate measurements, using pure chemicals and performing the reaction under the most ideal conditions is important to get a valuable percent yield.
How we calculate the percent yield?Percent yield of any chemical reaction is define as the ratios of the actual yield to the theoretical yield of the product and multiply by the 100.
To get the high percent yield or actual yield of any reaction, we have to perform the reaction under ideal condition because if we not use the standard condition then we get the low rate of reaction. Reactants should be present in the pure form as impurity make unwanted products and reduce the productivity of main product and accurate amount of reactants also important for the spontaneous reaction.
Hence, options (a), (b) & (c) are correct.
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Janet learns that Earth is tilted. Due to its tilt, some areas on the surface of Earth experience darkness for an entire day. Which plant process is affected most during this darkness?
root growth
root growth
reproduction
reproduction
photosynthesis
photosynthesis
water absorption
water absorption
Photosynthesis is that plant process is affected most during this darkness because photosynthesis only occurs when there is sunlight.
What is photosynthesis?Photosynthesis is a process in which water and carbondioxide combine in the presence of sunlight and produce glucose and oxygen. We know that Photosynthesis occurs only at daytime.
So we can conclude that Photosynthesis is affected during this darkness because photosynthesis only occurs when there is sunlight.
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PLEASE HELP!
what are the steps that occur during the combustion of hydrogen?
Answer:
In flame of pure hydrogen burning in air, the hydrogen (H2) reacts with oxygen (O2) to form water (H2O) with the release of energy. In atmospheric air rather than pure oxygen, hydrogen combustion may yield a small amount of nitrogen oxides with the water vapor. The energy released allows hydrogen to be used as a fuel.
Explanation:
Here are the steps that occur during the combustion of hydrogen; Initiation, Propagation, Completion, and Energy Release.
The combustion of hydrogen involves a chemical reaction with oxygen in the air, resulting in the release of energy in the form of heat and light.
Initiation: The combustion process begins by supplying energy to break the initial bonds in the reactant molecules. In the case of hydrogen combustion, heat or an external ignition source is provided to break the diatomic hydrogen molecules (H₂) into individual hydrogen atoms (H).
H₂ → 2H
Propagation: Once the hydrogen molecules are dissociated into hydrogen atoms, they react with oxygen (O₂) molecules from the air. This reaction occurs in a chain reaction mechanism involving three steps: initiation, propagation, and termination.
Initiation: Hydrogen atoms react with oxygen molecules to form hydrogen peroxide (H₂O₂) and hydroxyl radicals (OH).
H + O₂ → HO₂
H + HO₂ → H₂O₂
Propagation: The hydroxyl radical (OH) reacts with hydrogen molecules to form water vapor (H₂O) and release heat.
OH + H₂ → H₂0 + H
Termination: The chain reaction terminates when two radicals combine to form stable products.
H + OH → H₂0
Completion: The chain reaction continues as long as there is a sufficient supply of hydrogen and oxygen. The hydrogen atoms released in the propagation step can initiate further reactions with more oxygen molecules, leading to the complete combustion of hydrogen to form water vapor (H₂O).
H₂ + O₂ → H₂O
Energy Release: The combustion of hydrogen is an exothermic reaction, which means it releases energy in the form of heat and light. This energy is responsible for the heat and light produced by a burning hydrogen flame.
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Heat transfer through direct contact between molecules
Answer:
This is an example of a form of energy transferring itself. Tons of electrons are passed through the energy itself to you very quickly. That's why when we touch a hot surface and get burned, it's because our skin molecules are touching the heat molecules.