PLEASE HELP DUE IN EXACTLY 15 mins!! i will give you branliest

Answer:

Atomic mass = proton + neutron

31+33= 64

Number of proton = Atomic number = 31

Charge of element is +3

Explanation:

Answer:

2.5 g mass of Ra-226 will remain after 4800 years.

Explanation:

Given data:

Mass of Ra-226 = 20 g

Sample remain after 4800 years = ?

Solution:

Half life of Ra-226 = 1600 years

Number of half lives passed = T elapsed / half life

Number of half lives passed = 4800 year / 1600 year

Number of half lives passed = 3

At time zero = 20 g

At first half life = 20 g/2 = 10 g

At 2nd half life = 10 g/2 = 5 g

At 3rd half life = 5 g/2 = 2.5 g

Thus, 2.5 g mass of Ra-226 will remain after 4800 years.

Answer:

dinitrogen pentasulfide

Explanation:

The correct name for the compound N₂S₅ is Dinitrogen pentasulfide and the correct option is option C.

Naming of compounds refers to the systematic process of assigning names to chemical compounds based on their composition and structure. It involves following certain rules and conventions to generate appropriate names that accurately represent the chemical formula and characteristics of the compound.

In inorganic chemistry, naming compounds often involves identifying the elements present and specifying their respective oxidation states or charges. Various naming conventions, such as the Stock system and the common system, are used depending on the type of compound and the specific elements involved.

Thus, the ideal selection is option C.

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when forces are balanced the object does not move.

Explanation:

if you and your friend push both sides of the chair at the same time with the same amount of strength the chair wouldn't move.

The shortest distance taken by the object to reach the destination at a minimum time is called acceleration. Thus value acceleration depends upon the displacement and time.

Answer:

Circulatory System

Explanation:

Blood carries oxygen to the rest of the body, as well as glucose.

Answer: Sodium Nitrate solution is neutral.

Explanation: Sodium nitrate solution has strong bases and strong acids so it would have a neutral pH of 7.

Answer:As the tetrapod evolved, the number of digits decreased

Explanation:

Answer: During the evolution of the tetrapod limb, the number and pattern of elements along the proximal–distal axis (running from the shoulder to the fingers) has remained invariant, while the number and pattern of elements along the autopod anterior–posterior axis (thumb to little finger, also designated digi

Explanation:

Answer:

You can not see the sugar.

Explanation:

Answer: Since the vials are filled the same, and are placed on the same hot pad, all the water will evaporate at the same time

Explanation:

The source of error in the experiment  is the vials  being filled the same, and  placed on the same hot pad, all the water evaporating at the same time .

Errors in chemical analysis result when there is a difference between observed value and the true value.If the magnitude of errors is large , it results in decrease in accuracy, reproducibility, and precision.

There are three types of errors:1) random error 2) systematic error 3) human error.The cause of random errors are difficult to quantify while the human errors can be minimized by taking a range of readings to reduce the error.

Errors while measuring boiling point may be human errors while noting down the boiling temperature or instrumental or systematic error if there is a fault in the thermometer.

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Answer:

4104 Coulombs

Explanation:

charge = time(sec) *current

25*60 =1500+20=1520

2.7A * 1520 sec =4104

4104 C

Answer: If only max or min yes but if we have min and max that is a bad idea it is not as safe.

Answer:

Explanation:

yt

Answer:

129.5994 g/mol

Explanation:

Complete Question:

Theresa creates an experiment where she mixes two red-colored substances together in a container and observes the solution slowly changing from red to blue for the next eight minutes. The solution becomes completely blue after eight minutes. What does this represent about the type of change happening in the container?

Group of answer choices

A. A chemical change started immediately and finished at eight minutes.

B. A non-chemical change started immediately and finished at eight minutes.

C. A chemical change occurred at four minutes.

D. A non-chemical change occurred at four minutes.

Answer:

A. A chemical change started immediately and finished at eight minutes.

Explanation:

A chemical reaction can be defined as the chemical process which typically involves the reaction between two or more chemical elements (substances) to form a new compound, through the rearrangement of the ionic or molecular structure of each chemical element.

This ultimately implies that, a chemical reaction is a chemical change that immediately starts when two or more molecules of a chemical element (substance) known as reactants are combined together to form a new product (compound).

In this scenario, Theresa creates an experiment where she mixes two red-colored substances together in a container and observes the solution slowly changing from red to blue for the next eight minutes. The solution becomes completely blue after eight minutes. Thus, what this represent about the type of change happening in the container is that, a chemical change (from red to blue) started immediately and finished at eight minutes.

Answer:

Ld₂Mz

General Formulas and Concepts:

Chemistry - Compounds

Explanation:

Step 1: Define

"Lindenium" Ld w/ oxidation charge of +1

"Mendezine" Mz w/ oxidation charge of -2

Step 2: Write Compound

To balance out the charges to be neutral (0), we must counter balance the amount of Ld's with Mz's. We need 2 Ld's with 1 Mz to create a compound with a neutral charge:

2Ld¹⁺ + Mz²⁻

2(+1) + (-2) = (+2) + (-2) = 0 (neutral charge)

Therefore, our compound must be Ld₂Mz.

Answer:

fullerene

Explanation:

Answer: 1400 mL

Explanation:

The change in volume with change in pressure and change in temperature can be calculated using combination of gas laws. Here, the change in volume is 5600 ml.

Boyle's law, Charles's law and Gay- Lussacs law all relating the temperature, pressure and volume of an ideal gas. The relation between these three parameters from the combination of these laws at conditions is written as:

P1 V1/T1 = P2 V2/ T2.

From this, the change in volume V2 can be calculated.

Given , P1 = 760 mmHg

T1 = 20 k and V1 = 1400 mL.

T2 = 40 k and P2 = 380 mmHg.

The new volume V2 = P1 V1 T2 / T1 P2.

                                  = (760 mmHg × 1400 ml × 40K) / (20 K × 380 mmHg)

                                  = 5600 mL.

Therefore, the change in volume of the gas is 5600 ml.

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Answer:

0.17×10⁻³ mol

Mass = 0.00476 g

Explanation:

Given data:

Number of molecules of N₂ = 1 ×10²⁰ molecules

Number of moles of N₂ = ?

Mass in gram of N₂ = ?

Solution:

1 mole of any substance contain 6.022×10²³ molecules

1 ×10²⁰ molecules× 1 mol /6.022×10²³ molecules

0.17×10⁻³ mol

Mass in gram:

Mass = number of moles × molar mass

Mass = 0.17×10⁻³ mol × 28 g/mol

Mass = 4.76×10⁻³  g

Mass = 0.00476 g

Explanation:

Agl+hih+356bnh$&56DG hug zero cg hydh hod sir un bucks

Answer: Metals: Li, Be, Na, Mg, Al, K, Ca, Sc, Ti, V, Mn, Fe, Co, Ni, Cu, Zn

Non-metals: H, He, C, N, O, F, Ne, Si, P, S, Cl, Ar

Metalloid: B

Explanation: The first 30 elements are H, He, Li, Be, B, C, N, O, F, Ne, Na,

Mg, Al, Si, P, S, Cl, Ar, K, Ca, Sc, Ti, V, Mn, Fe, Co, Ni, Cu, Zn

Metallic elements are more electropositive (tending to form ions by donating electrons) with fewer electrons in their outer shell

Non-metallic elements are more electronegative (tending to form ions by accepting electrons) with more electrons in their outer shell

Metalloids are elements somewhere between, but without any specific clear boundary between them and metals/non-metals

group1 and group2 elements, with one or two outer electrons, are all metals: Li, Na, K, Be, Mg, Ca

similarly the transition metals 21-30 are all electropositive and metals.

The noble gases He, Ne, Ar are gases that have completed outer shells and are non-metallic, likewise the halogens F, Cl with 7 outer electrons, and  O and S with 6 are non-metals. N and P (5 outer electrons) are non-metallic as are C and Si (4 outer electrons).

This leaves H, B, Al. H, with its single electron close to the nucleus is a non- metallic gas. Al (3 outer electrons) is metallic, but B, has its 3 electrons close to the nucleus and has the in-between character of a metalloid.

Answer:

Microwaves

Explanation:

Microwaves have more energy than blue light

Among microwaves or blue light, blue light has a higher frequency. This is because blue light belongs to the visible region has a short wavelength and produces a higher amount of energy.

The frequency of any wave is inversely related to the wavelength. This means that when the frequency of the wave increases, the wavelength decreases. While the relationship between frequency is directly related to the energy.

According to the context of this question, gamma rays have the highest frequency and shorter wavelength, while radiowaves have a shorter frequency and the highest wavelength.

Therefore, blue light has a higher frequency. This is because blue light belongs to the visible region has a short wavelength and produces a higher amount of energy.

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Answer:

Solubility

Explanation:

Solubility units that incorporate units of solution include grams of solute per 100 grams of solution or grams of solute per liter of solution. Another way to express solubility is in moles of solute per liter of solution; this ratio is called "molarity."

Answer:

Mass = 17.8 g

Explanation:

Given data:

Number of atoms of Ca = 2.68 × 10²³

Mass in gram = ?

Solution:

Avogadro number:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

1 mole = 6.022 × 10²³ atoms

2.68 × 10²³ atoms × 1 mole  /6.022 × 10²³ atoms

0.445 mol

Mass in gram;

Mass = number of moles ×  molar mass

Mass = 0.445 mol  ×  40 g/mol

Mass = 17.8 g

Answer:

A (option) .............

Answer:

Al2O3

Explanation:

ZnO,Al2O3,PbO2 are some of the amphoteric oxides

Amphoteric oxides are metal oxides that can react with both acids and bases,so Aluminum oxide can react with both HCl and Sodium hydroxide which is a base

Answer:

B: 1s²2s²2p¹

Na: 1s²2s²2p⁶3s¹

Explanation:

A = 2

B = 1

C = 2

D = 6

E = 1

Hope that helps.

Answer:

B: 1s2 2sA2pB

A = 2

B = 1

Na: 1s22sC2pD3sE

C = 2

D = 6

E = 1

Answer:

Calcium

Explanation:

Answer:

As the kinetic energy of the gaseous solute increases, its molecules have a greater tendency to escape the attraction of the solvent molecules and return back to the gas phase. As a result, the solubility of a gas decreases as the temperature increases.

Explanation:

Answer:

0.768 m

Explanation:

1 cm = 0.01 m

76.8 cm * 0.01 m/ 1 cm

0.768 m