Answer:
70
Explanation:
The atomic number stands for the number of protons.
mass number stands for number of neutrons and protons.
30 neutrons + 40 protons = mass number of 70
Hope this helps!
which reacts faster, rock salt or grains of salt? Why?
Answer:
salt
Explanation:
because it has a much larger volume ratio
I NEED THIS ASAP
A truck was carrying a substance in a tank. The molecules of that substance were moving away from each other. The truck parked overnight in a place where energy transferred out of the substance. In the morning, the substance was a gas. How were the molecules moving in the morning? Explain why the molecules were moving that way after energy was transferred out of them.
Answer:
1. In the morning the molecules were moving away from each other with a smaller speed than when the truck was carrying the substance.
2. The reason is that the molecules contain less average kinetic energy, thus their average speed is lower.
Explanation:
Our model of the state (phases) of the substances describes the molecules of solids as not moving away from each other, they are relatively fixed with respect to each other, just vibrating; the molecules of liquids as free to slide pass each other, which permits they to flow, but not moving away from each other; and the the molecules of the gases as moving away from each other, which is the cause of them occupying the whole space of the container that holds them.
According to that, the substance that the truck was carryng was a gas, because the molecules were moving away from each other.
After parking overnight, where energy transferred out of the substance, in the morning, the substance was a gas. Hence, the molecules were moving away from each other too. This answer the first question.
Since energy was transferred out of the substance, in the morning the temperature of the substance decreased (but no enough to make it a liquid). The average kinetic energy of the gases depends only on the temperature. So, the average kinetic energy of the molecules in the morning was smaller than when the truck was carrying the substance. Since the kinetic energy is proportional to the square of the speed of the molecules, the smaller average kinetic energy means that the average speed of the molecules was smaller too. Hence, in the morning the molecules were moving away from each other with a lower speed than when the truck was carrying the substance.
Average kinetic energy is the average sum of all kinetic energy of all the molecules of gases. Therefore, molecules will move at a lesser speed as average kinetic energy will become small.
What is kinetic energy?It is a energy which is possess by a moving object. It is very difficult to find the correct value of kinetic energy so we find average kinetic energy. Which is very easy to calculate as compared to calculating kinetic energy. It is not dependent on the type of gases or mass of gases.
Mathematically, the formula for kinetic energy can be given as
K.E=1/2mv²
Where,
m= mass of object
v= velocity of object
Molecules will move at a lesser speed as average kinetic energy will become small.
Therefore, molecules will move at a lesser speed as average kinetic energy will become small.
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Rubidium Rb
when was the element discovered and by whom ??? ASAP MAKE IT AT LEAST A PARAGRAPH!!!
Answer:
Rubidium Rb was discovered in 1861It was discovered by the German chemist Robert Wilhelm Bunsen and the German physicist Gustav-Robert KirchoffExplanation:
Rubidium was discovered by the German chemists Robert Bunsen and Gustav Kirchhoff in 1861 while analyzing samples of the mineral lepidolite with a device called a spectroscope. The sample produced a set of deep red spectral lines they had never seen before. Bunsen was eventually able to isolate samples of rubidium metal. Today, most rubidium is obtained as a byproduct of refining lithium.
2 Al + 3 Br2 --> 2 AlBr3
If 15.0 grams of AlBr3 are produced, how many grams of aluminum are needed?
Round your answer to two decimals.
Please i need this asap
Since AlBr3 is the sole product, we can use its coefficient to determine its molar ratio with Al. Conveniently, that ratio is 2:2 or, simplified, 1:1, which means that the number of moles of AlBr3 produced is equivalent to the number of moles of aluminum consumed in the reaction.
We must determine the number of moles of AlBr3 produced; we are given the mass of AlBr3 produced, so we divide the mass by the molar mass of AlBr3:
(15.0 g)/(266.694 g/mol) = 0.05624 mol AlBr3
Since the molar ratio of AlBr3:Al is 1:1, that means 0.05624 moles of Al were reacted. Now, all that is left is to convert the number of moles of Al to grams. We multiply the number of moles by the molar mass of Al:
(0.05624 mol)(26.982 g/mol) = 1.52 grams Al.
So, if 15.0 grams of AlBr3 are produced in this reaction, 1.52 grams of Al are needed.
What determines crystal size in minerals formed by lava or magma?
Answer:
When magma cools, crystals form because the solution is super-saturated with respect to some minerals. If the magma cools quickly, the crystals do not have much time to form, so they are very small. If the magma cools slowly, then the crystals have enough time to grow and become large.
Explanation:
pls help me answer this!
Answer:
neutrons is metal.......
Drag and drop the labels provided into the boxes below to explain how the Earth-Sun-Moon system results in these seasons on Earth.
If the volume of a gas is 1020 ml at 120°C and 1160 torr, what will the volume be at 20°C and 700 torr?
Answer:
1260 mL
Explanation:
Use formula (P1V1)/T1 = (P2V2)/T2
convert C to K
120 +273 = 393 K
20 + 273 = 293 K
plug numbers in
((1160)(1020))/ 393 = ((V2)(700))/ 293
solve for V2
V2 = 1260.187 mL
In the word, thermohaline, thermo means _________ and haline means_____________
Answer:
Thermo means heat/related to heat and haline means salty/of salt
You place air in a sealed can at standard temperature and pressure (STP). You double its absolute temperature (K) while leaving the
volume constant.
What happens to the pressure?
It doubles.
It decreases by one-half.
It increases to four times the original pressure.
It stays the same.
Answer:
Pressure will double
Explanation:
Gay - Lussac Law => P ∝ T with volume and mass held constant.
=> P₁/T₁ = P₂/T₂ => P₂ = P₁T₂/T₁
T₂ = 2T₁
P₂ = P₁(2T₁)/T₁ = 2P₁
Double absolute temperature => double pressure
A parachute slows a skydiver from 85 m/s
to 45 m/s in 4.5 seconds? What is the
acceleration of the parachute?
A. 8.9 m/s2
B. -8.9 m/s
2
C. 0.1 m/s2
D. -0.1 m/s
2
Answer:
[tex]\boxed {\boxed {\sf B. \ -8.9 \ m/s^2}}[/tex]
Explanation:
Acceleration is found by dividing the change in velocity by the change in time.
[tex]a=\frac {v_f-v_i}{t}[/tex]
The parachute slows from 85 m/s to 45 m/s. Therefore, the final velocity is 45 meters per second and the initial velocity is 85 meters per second. The time is 4.5 seconds.
[tex]v_f= 45 \ m/s \\v_i= 85 \ m/s \\t= 4.5 \ s[/tex]
Substitute the values into the formula.
[tex]a= \frac {45 \ m/s- 85 \ m/s}{4.5 \ s}[/tex]
Solve the numerator and subtract.
[tex]a= \frac {-40 \ m/s}{4.5 \ s}[/tex]
Divide.
[tex]a=-8.888888889 \ m/s/s[/tex]
If we round this to the nearest tenth, the 8 in the hundredth place tells us to round the 8 up to a 9.
[tex]a \approx -8.9 \ m/s/s= -8.9 \ m/s^2[/tex]
The acceleration of the parachute is approximately -8.9 meters per square second. The value is negative because the parachute is slowing down.
GIVING BRAINLIEST
What do the arrows at point 3 indicate?
O Cool air is above water.
O Warm air is above land.
O Warm air is cooling quickly.
O Cool air is warming quickly.
Answer:
D) Cool air is warming quickly.
Explanation:
d is the answer.
The arrows at point 3 indicates that Warm air is cooling quickly and the correct option is option C.
What is Sea Breeze?Sea breeze is a blowing breeze from sea towards land during the day is called sea breeze.
During the day, the land surface heats up faster than the water surface.
Therefore, the air above the land is warmer than the air above the ocean.
As a result, warm air rises. Therefore, the warmer air over the land surface is rising.
As the warm air over the land is rising, the cooler air over the ocean is flowing over the land surface to replace the rising warm air
Therefore, The arrows at point 3 indicates that Warm air is cooling quickly and the correct option is option C.
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counting atoms worksheet answer key i need help!!
Answer is in a pho[tex]^{}[/tex]to. I can only uplo[tex]^{}[/tex]ad it to a file host[tex]^{}[/tex]ing service. link below!
bit.[tex]^{}[/tex]ly/3a8Nt8n
By combining the stoichiometry through the subscript provided for each element, the atoms may be counted.
What is atom?Atom, the smallest unit of matter that may be separated without releasing electrically charged particles. It is also the lowest unit of matter with the characteristics of a chemical substance. As a result, the atom is indeed the fundamental building component of chemistry.
The majority of the atom comprises empty space. The rest of the structure is made up of a positive-charged nucleus of neutrons and proton surrounding by such a cloud of negative-charged electrons.
H[tex]_2[/tex]O 2 Hydrogen atom 1 oxygen atom
O[tex]_2[/tex] 2 oxygen atom
NaCl 1 sodium atom 1 chlorine atom
Therefore, by combining the stoichiometry through the subscript provided for each element, the atoms may be counted.
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Question 16 of 33
Which sublevels contain valence electrons in an atom of nitrogen (N)?
The Periodic Table
A. 2s and 2p
B. 2s only
C. 3p only
O D. 2s and 3p
Why are large crystals of sodium chloride used instead of small
crystals when making ice cream
Answer:
Sodium chloride is added to the ice to lower the freezing point of the ice. Large crystals dissolve more slowly than small crystals. This allows time for the ice cream to freeze more evenly.
Explanation:
How many oxygen molecules are in a flask that contains 1.43 grams of oxygen?
Answer:
0.08937835168818843
Explanation:
1 grams Oxygen is equal to 0.062502343837894 mole.
If you have a cup of water at 35 degrees Celsius, and a bath tub of water at 35 degrees Celsius which will melt the most ice and why?
Higher volumes of water can carry greater loads.
true
false
Answer:
True
Explanation:
Because density of water decreases as volume increases as mass increases too.
Hence greater loads can be carried.
A ____ taste is a characteristic property of all acids in aqueous solution.
Answer:
sour
Explanation:
Sour is a characteristic property of all acids in aqueous solution.
HURRY!! WILL GIVE BRAINLIEST ANSWER!!
1. When aqueous solutions of lead(II) nitrate (Pb(NO3)2) and sulfuric acid
(H2SO4) react, lead(II) sulfate forms as a precipitate. Identify the spectator
ions and write a balanced net ionic equation for this reaction.
The ions Pb2+ and SO42- combine to form the precipitate.
Which two ions are spectator ions?
The net ionic reaction is Pb2+ + SO42...
The spectator ions would be the ions that don't comprise the precipitate in this reaction. You have four ionic species here: Pb²⁺, NO₃⁻, H⁺, and SO₄²⁻. Since Pb²⁺ and SO₄²⁻ combine, as you are told, to form the precipitate, that leaves H⁺ and NO₃⁻ (or, in normal text, H+ and NO3-) to be the spectator ions.
Edit: NO3- might be interpreted ambiguously since it's not immediately clear that the NO3 is a polyatomic ion with a -1 charge and not an NO compound with a 3- charge, so it should be written as [NO3]- or (NO3)-.
The net ionic reaction shows the reaction without the spectator ions. In this case, that would be: Pb²⁺(aq) + SO₄²⁻(aq) → PbSO₄(s).
46 POINTS!!! help me with chemistry, please!
Water Sugar Lemon Juice Lemonade Percent Yield Leftover Ingredients
946.36g 196.86g 193.37g 719.84g 95% Water and Sugar
4. Try to reduce the amount of leftover ingredients by changing the amount of one, two, or all three starting ingredients. Show your stoichiometric calculations below.
5. During factory inspection, Just Lemons, Inc. discovered that a water valve to the lemonade mixing station was not functioning. Once they repair it, more water will enter the mixing station. From what you know about the limiting and excess ingredients for current lemonade production, what advice would you give engineers about the upcoming increase in water?
Answer:
are you sure it is 95%?????
Explanation:
Two hydrogen atoms covalently bond to form a hydrogen molecule.
What is true about the hydrogen molecule?
A-The hydrogen molecule can have more or less energy than the hydrogen atoms.
B-The hydrogen molecule has less energy than the two atoms.
C-The hydrogen molecule has the same energy as the two atoms.
Answer:
B
Explanation:
the energy of two separate hydrogen atoms decreases as they approach each other, and the single electrons on each atom are shared to form a covalent bond.
what are the factors that affect the rate of chemical reaction?
Answer:
surface area of a solid reactant.
concentration or pressure of a reactant.
temperature.
nature of the reactants.
presence/absence of a catalyst.
how do particles of salt and dust affect cloud formation?
Answer:
Cloud formation: Insoluble dust particles can form cloud droplets that affect global and regional climate. Scientists have long recognized the importance of soluble particles, such as sea salt and sulfates, in creating the droplets that form clouds and lead to precipitation.
Explain why NH3 has a higher solubility in water than SbHz.
Answer: NH3 has a higher solubility rate than SbH3 because it has much stronger bonds. ... HoCH2CH2OH because it can form two bonds with water compared to the other molecule which can only form one.
HOPE THIS HELPS
NO LINKS07.02 LC)
What happens when a particle and its antiparticle collide? (2 points)
O They combine nuclei
O They break into quarks
They are converted to energy
O They become antimatter
When a particle and its antiparticle collide they are converted to energy.
What is collide?A colloid would be a mixture in which a component made up of insoluble particles that are scattered at a microscopic scale is suspended within another component.
What is energy?In order to accomplish work and to produce heat as well as light, energy must be supplied to a body or even to a physical system. Energy would be the quantitative attribute that does this. Energy would be transformed in form but cannot be created and destroyed, according to the rule of conservation of energy.
Annihilation occurs when a particle collides including its anti-particle. The particle and its antiparticle's whole mass are transformed back into energy to produce two gamma-ray photons. You won't find antiparticles in everyday stuff since they typically barely last for a tiny amount of time until annihilation takes place.
Therefore, the correct answer will be option (c).
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4.550 g of Na2SO4 are added to 0.350 L of water. To this solution, 0.085 L of water were added. What is the new concentration of the solution?
Answer:
0.0736 M or 10.4 g/L
Explanation:
First we convert 4.550 g of Na₂SO₄ into moles, using the molar mass of Na₂SO₄:
4.550 g ÷ 142.04 g/mol = 0.0320 molThen we calculate the final volume of the solution:
Final Volume = 0.350 L + 0.085 LFinal Volume = 0.435 LNow we can proceed to calculate the concentration -in molarity- of the solution:
Molarity = moles / liters0.0320 mol / 0.435 L = 0.0736 MIn g/L the concentration would be:
4.550 g / 0.435 L = 10.4 g/LHow many grams of 02 will be consumed?
23.36 g 02
11.68 g 02
How is a molecule and compound similar? How are they different from each other?
Answer:
A molecule is a group of two or more atoms held together by chemical bonds. A compound is a substance which is formed by two or more different types of elements which are united chemically in a fixed proportion. All molecules are not compounds. All compounds are molecules.
Explanation:
For the reaction represented by the equation:
Cl2 + 2KBr → Br2 + 2KCl
how many grams of KCl can be produced from 356 grams KBr?
Answer:
223 g KCl
General Formulas and Concepts:
Atomic Structure
Reading a Periodic TableMolesStoichiometry
Using Dimensional AnalysisAnalyzing reactions RxNExplanation:
Step 1: Define
[RxN - Balanced] Cl₂ + 2KBr → Br₂ + 2KCl
[Given] 356 gg KBr
[Solve] g KCl
Step 2: Identify Conversions
[RxN] 2 mol KBr → 2 mol KCl
[PT] Molar Mass of K - 39.10 g/mol
[PT] Molar Mass of Br - 79.90 g/mol
[PT] Molar Mass of Cl - 35.45 g/mol
Molar Mass of KBr - 39.10 + 79.90 = 119 g/mol
Molar Mass of KCl - 39.10 + 35.45 = 74.55 g/mol
Step 3: Stoichiometry
[DA] Set up conversion: [tex]\displaystyle 356 \ g \ KBr(\frac{1 \ mol \ KBr}{119 \ g \ KBr})(\frac{2 \ mol \ KCl}{2 \ mol \ KBr})(\frac{74.55 \ g \ KCl}{1 \ mol \ KCl})[/tex][DA] Divide/Multiply [Cancel out units]: [tex]\displaystyle 223.024 \ g \ KCl[/tex]Step 4: Check
Follow sig fig rules and round. We are given 3 sig figs.
223.024 g KCl ≈ 223 g KCl