Gather data: Four other pairs of elements in the same chemical family are listed below. List the number of valence electrons in each element. Beryllium Nitrogen Oxygen Fluorine Magnesium Phosphorus Sulfur Chlorine

Answer:

yes

Explanation:

yes

Answer: B. triH sol Mgl2= -triHlat+ triHhydr Mg^2+ 2triHhydr^l-

Explanation:

Just did it and it was right

Answer:

The kinetic molecular theory of matter states that: Matter is made up of particles that are constantly moving. All particles have energy, but the energy varies depending on the temperature the sample of matter is in. This in turn determines whether the substance exists in the solid, liquid, or gaseous state.

Explanation:

Answer and Explanation:

Yes. The determination of melting point is used to analyze if a solid compound is pure or impure. The melting point of a pure solid product does not vary in a narrow range, whereas if impurities are present the solid melts in a broad range of temperatures. For this reason, this technique is generally used to determine the identity and purity of the products obtained in chemical reactions.

The question is incomplete, the complete question is found in the image attached.

Answer:

1- acceptor

2-donor

3-acceptor

4-donor

Explanation:

A hydrogen bond acceptor is a molecule that has an electronegative atom having a lone pair of electrons that participates in the hydrogen bond.

A hydrogen bond donor is the molecule that supplies the hydrogen atom of a hydrogen bond.

If we look at structure I-IV in the image attached, I and III are hydrogen bond acceptors because they all possess electronegative atoms having lone pairs of electrons but do not have hydrgen atoms bonded to highly electronegative atoms.

Similarly, structures II and IV are hydrogen bond donors. The C=C double bond is electron withdrawing and highly electronegative making the hydrogen atoms attached to it acidic and hydrogen bond donors. Also, nitrogen is an electronegative atom thereby making structure IV a hydrogen bond donor.

the ph is gonna be your value and the 4 is gonna be your main subject

so as the ph is your value u gonna ad your ph and 7 and 4 toghter then multiple your answer 2 times  because ph represent multiple and your value  

Answer:

Unlike a permanent magnet, an electromagnet can be turned on and off using electrical current. Many variables affect the strength of this electromagnet, and there are some variables that do not affect the strength. ... Making the nail longer will not make the magnet stronger, unless you also add more turns to the coil.

electromagnet can be turned on and off using electrical current. Many variables affect the strength of this electromagnet, and there are some variables that do not affect the strength

Answer:

there are 7 total oxygen (O) atoms are present in in the reactants side of the equation

Answer:

thermal conductors

steel

polystyrene

thermal insulator

between things of the same temp?

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Answer:

116.78 grams.

Explanation:

1 mol of Strontium (Sr) = 87.62 grams

1.38 mol of Strontium = x

Cross Multiply

1 * x = 1.38 * 87.62

x = 116.78  grams

Answer: Percent recovery is 47.34 %

Explanation:

Percent yield is defined as the ratio of experimental yiled to theoretical yield in terms of percentage.

[tex]{\text{ percent yield}}=\frac{\text{amount recovered}}{\text{total amount}}\times 100[/tex]

Putting in the values we get:

[tex]{\text{ percent yield}}=\frac{0.732}{1.546}\times 100=47.34\%[/tex]

Therefore, the percent recovery is 47.34 %

The molecular formula of hydrate : CaCl₂.6 H₂O

So there are 6 molecules of H₂O

Given

54.7g CaCl₂ and 53.64 g H₂O

Required

The number of molecules H₂O

Solution

mol CaCl₂ :

= mass : MW

= 54.7 : 111 g/mol

= 0.493

mol H₂O :

= 53.64 : 18 g/mol

= 2.98

mol ratio H₂O : CaCl₂ :

= 2.98/0.493 : 0.493/0.493

= 6 : 1

Answer:

color

Explanation:

Answer:

D

Explanation:

The five conditions of chemical change: color chage, formation of a precipitate, formation of a gas, odor change, temperature change and the others are just physical changes that would happen if you change containers, or let it evaporate.

Answer:

0.41 atm

Explanation:

A reaction between liquid reactants takes place at 10.0 °C in a sealed, evacuated vessel with a measured volume of 5.0 L. Measurements show that the reaction produced 13. g of sulfur hexafluoride gas. Calculate the pressure of sulfur hexafluoride gas in the reaction vessel after the reaction. You may ignore the volume of the liquid reactants. Round your answer to 2 significant digits.

Step 1: Given data

Step 2: Convert "T" to Kelvin

We will use the following expression.

K = °C + 273.15

K = 10.0 °C + 273.15 = 283.2 K

Step 3: Calculate the moles (n) of SF₆

The molar mass of SF₆ is 146.06 g/mol.

13. g × 1 mol/146.06 g = 0.089 mol

Step 4: Calculate the pressure (P) of SF₆

We will use the ideal gas equation.

P × V = n × R × T

P = n × R × T/V

P = 0.089 mol × (0.0821 atm.L/mol.K) × 283.2 K/5.0 L = 0.41 atm

Answer:

1. B 2.B

Explanation:

Answer:

its C

Explanation:

1/74.44 * 79.75 = 1.07

The molarity (mol/L) of NaClO in the bleach, given the data is 1.07 mol/L (Option C)

Molarity is defined as the mole of solute per unit litre of solution. Mathematically, it can be expressed as:

Molarity = mole / Volume

Mass of solute = percent × mass of solution

Mass of NaClO = 7.25% × 1100

Mass of NaClO = 0.0725 × 1100

Mass of NaClO = 79.75 g

Mole = mass / molar mass

Mole of NaClO = 79.75 / 74.44

Mole of NaClO = 1.07 mole

Molarity = mole / Volume

Molarity of NaClO = 1.07 / 1

Molarity of NaClO = 1.07 mol/L

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Answer: B. They reproduce slower than unicellular organisms

Explanation:

In unicellular organisms there is a single cell which performs all the functions like digestion, respiration, and reproduction. The cell reproduce by cell division. The single parent cell divides into two identical daughter cells. But multicellular organisms exhibit multiple cells and their reproduction is complex. They reproduce by sexual mode of reproduction in which separate sex cells are produced when they fuse form zygote which is the precursor of new organism. This process is slower than that of the cell division and production of progeny by the unicellular organisms. Thus reproduction is slower in multicellular organism this is the disadvantage in multicellular organisms.

Answer:

B. they reproduce slower than unicellular organisms

Explanation:

Answer:

1000 kJ.mmole / 1000 J.mole

Explanation:

To solve this, we need to analyze the given data.

We have a number which is 87.1 J/mmole.C (I'm assuming it has the J at the beggining because if not, then you are missing some data) and the final result is kJ/mol.C

The only unit that has not changed in the process was the °C, while the mole and J change respectively. In this case, we need to know the conversion factor of mmole to mole and J to kJ.

In the case of a mole:

1 mole --------> 1000 mmole

In the case of Joule:

1 kJ ----------> 1000 J

So the first thing we will do is to change from J to kJ:

87.1 J * 1 kJ / 1000 J = 0.0871 kJ

Now let's convert mmol to mole:

0.0871 kJ/mmole.C * 1000 mmole / 1 mole = 87.1 kJ/mole.C

As you can see, there's is practicly no change at all with the units, so putting all together it would be:

Hope this helps

Answer:yes anything can be addictive

Explanation:

Answer:

While caffeine produces a small rise in dopamine, it does not cause the large surge that unbalances the reward circuits in the brain and is necessary for an addiction. So even though the word “addiction” is often used casually, caffeine is not addictive (scientifically speaking).

Answer:

False

Explanation:

Chemists make a distinction between two different types of changes that they study—physical changes and chemical changes. Physical changes are changes that do not alter the identity of a substance. Chemical changes are frequently harder to reverse than physical changes.

The lethal dose and how ounces of soda in a can of soda is not given, however, the standard lethal dose and volume of soda are given as below:

Lethal dose: 10 gm of caffeine

The volume of soda per can =  12oz/can

Answer:

The correct answer is - 324.254 cans or round up to 325 cans. Ans.

Explanation:

Given:

2.57 mg caffeine / 1oz

12oz / 1can

Lethal dose: 10.0g or 10,000mg of caffeine

Solution:

Caffeine per soda can = (2.57 mg caffeine / 1oz) * (12oz / 1can) = 30.84 mg caffeine / 1can.

lethal dose would be in =

(10,000mg caffeine) * (1can / 30.84 mg caffeine) = 324.254 cans or round up to 325 cans. Ans.

Answer:

C. Plate tectonic collisions can create mountains.

Answer:

They can make them larger

Explanation:

They go up under a mountain and then the mountains rise up

Answer:

Explanation:

From the given information:

The accuracy depends on the internal diameter of the cylinder. The cylinder with the least internal diameter is obviously more precise.

Let's assume 1% is the error of measurement.

Then, to measure 70 mL from 10 mL cylinder

The error = [tex]10 \times \dfrac{1}{100} \times 7[/tex]

= 0.7 mL

However; for a 100 mL cylinder, the error = 1 mL

Now,

The total volume for 10 mL = (70 + 0.7) = 70.7 mL

The total volume for 100 mL = (70 + 1 ) = 71 mL

Suppose the density (d) is same for both

Then;

the mass of 10 mL = ( d × 70.7) g

the mass pf 100 mL = (d × 71) g

Thus, the mass of 100 mL is greater than that of 10 mL.

Answer:

Their must be a picture with this question so we can answer it

Explanation:

According to octet rule  the bonded valence shells are completely filled. All the compounds except the first one, CH₃CH₃O is invalid since H does not obey the rule and invalid.

Octet rule says that an atoms become stable when it completes its valence shell to 8 electrons or 2 electrons for K-shell. Thus bonded shells have to completely filled to be stable.

Each atom shares its electrons based on its valency. For example carbon have a valency of 4 and it forms for bonds and oxygen and sulfur have two and hydrogen forms only one bonds.

In the first compounds CH₃CH₃O, where one H forms two bonds which is not possible and invalid.

In the second compound CONH, all the atoms satisfies its valency including nitrogen having a valency of three forms  three bonds. Similarly in CH₂F₂, one fluorine forms one bond and the structure is valid.

In the case of Br₂ , each bromine shares one electron with the other and complete their octet to eight electrons. In NH₃, SCO and COCl₂ all the atoms satisfies their valency and the structures are valid.

Therefore the only invalid structure is first compound, remaining all are valid.

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Your question is incomplete. But most probably your complete question was as in the uploaded image.

Answer:

In advance

middle

lower

Explanation:

These are the safety precautions needed when carrying out duties in the fume hood.

When planning and preparing to work in a fume hood (a locally designed area to reduce exposure to hazardous fumes). It is advisable to make all equipment readily available at your disposal in advance to reduce and minimize the raising and lowering of the hood sash at intervals.

It is also pertinent to understand that working in the middle of the work surface helps to promote the movement of air and keeps the area neat and tidy.

However, if any case where there is a need to get a new tool or equipment during the process of working in a fume hood, it is advisable to lower the sash at that point in time.

Answer:

25 mM Tris HCl and 0.1% w/v SDS

Explanation:

A 10X solution is ten times more concentrated than a 1X solution. The stock solution is generally more concentrated (10X) and for its use, a dilution is required. Thus, to prepare a buffer 1X from a 10X buffer, you have to perform a dilution in a factor of 10 (1 volume of 10X solution is taken and mixed with 9 volumes of water). In consequence, all the concentrations of the components are diluted 10 times. To calculate the final concentration of each component in the 1X solution, we simply divide the concentration into 10:

(250 mM Tris HCl)/10 = 25 mM Tris HCl

(1.92 M glycine)/10 = 0.192 M glycine

(1% w/v SDS)/10 = 0.1% w/v SDS

Therefore the final concentrations of Tris and SDS are 25 mM and 0.1% w/v, respectively.

Answer: Gravity will pull two objects together.

Explanation: It’s newton’s 1 and kinda his 2 law.