my chem test is tomorrow!! please help

Answer:

380

Explanation:

I couldn't find the answer anywhere so this is the correct answer. I got it graded.

Answer: Molarity when 25.0 g of the compound [tex]NaClO_{3}[/tex]is placed in 85.0 mL of solution is 294.12 M.

Explanation:

Given: Mass = 25.0 g

Volume  = 85.0 mL (1 mL = 0.001 L) = 0.085 L

Molarity is the number of moles of a substance divided by volume in liter.

Hence, molarity of given solution is calculated as follows.

[tex]Molarity = \frac{mass}{Volume (in L)}[/tex]

Substitute the values into above formula as follows.

[tex]Molarity = \frac{mass}{volume (in L)}\\= \frac{25.0 g}{0.085 L}\\= 294.12 M[/tex]

Thus, we can conclude that molarity when 25.0 g of the compound [tex]NaClO_{3}[/tex]is placed in 85.0 mL of solution is 294.12 M.

Answer:

A they share two covalent bonds

Answer:

najah zggs haihß hajoa ha8 a an àjàhajß

Answer:

Increased the concentration

Explanation:

Complete Question

Open the simulation by pushing the play button.  Begin by dragging the concentration tester overto the liquid and add drink mix until the concentration reaches approximately 2.oo mol/L.  This means there are 2.00 moles of the drink mix in 1 Liter of the solution. Add more drink mix until you notice a color change. Have you increased or decreased the concentration? (Higher number means a higher concentration).

Solution

Drink mix is basically the solute which is added to solvent i.e water.

The higher is the amount of drink mix in the solvent, the higher is the concentration of the solute and hence darker is the color of the drink.

Hence, in the case the concentration of the drink has been increased.

Answer:

2

Explanation:

Answer:

n = 2.18 moles

Explanation:

Given that,

Mass = 127.5g

Molar mass of NaCl = 58.44 g/mol

We need to find the number of moles. We know that,

No. of moles = Given mass/molar mass

Put all the values,

[tex]n=\dfrac{127.5\ g}{58.44\ g/mol}\\\\n=2.18\ moles[/tex]

Hence, there are 2.18 moles of 127.5g of NaCl.

Zinc sulfide (or zinc sulphide) is an inorganic compound with the chemical formula of ZnS. This is the main form of zinc found in nature, where it mainly occurs as the mineral sphalerite.

Answer:

since an oxygen atom normally has 8 protons and 8 electrons, this ion has 10 electrons (-10 charge) and 8 protons (+8 charge) giving it a charge of -2 (-10 + 8 = -2).

Explanation:

Answer:

NaHCO3(s) → NaOH(s) + CO2(g)

Explanation:

A balanced chemical equation is that in which the number of atoms of each element on the reactant side is equal to the number of atoms of each element on the product side.

Based on the following equation below, each atom on the reactant side matches the ones on the product side, hence, the equation is said to be balanced. The balanced equation is as follows:

NaHCO3(s) → NaOH(s) + CO2(g)

Answer: Hello your question is incomplete attached below is the complete question with the missing diagrams

a) The angle = 120°

  hybridization = sp2

b)  The angle = 120°

  hybridization = sp2

Explanation:

a) using VSPER to predict bond angles

Given that there is the presence of 1 double bond to C and 2 single bonds one to C and one to H around the marked atom which equals 3 sets of electrons surrounding the central atom.

hence according to VSPER theory the angle = 120° while the Hybridization = sp2

b) Using VSPER to predict bond angles at marked atom

Given that there is  There is 1 double bond to C and 2 single bonds to the different C atoms respectively around the marked atom, which makes 3 sets of electorns surrounding the central atom

hence according to VSPER theory the angle = 120° while the Hybridization = sp2

Answer:

Explanation:

THE BEST ANSWER IS CCC

Answer:

Three things are necessary for corrosion to occur: an electrolyte, an exposed metal surface, and an electron acceptor. Corrosion can be prevented by removing one of these conditions. Coating a metal surface with paint or enamel provides a barrier between the metal and the moisture in the environment.

Answer:

B) 2

Explanation:

This is because the element in discussion is magnesium which has 12 protons and it falls in group 2 (the second column in periodic table)

Answer:

Tribhuvan University is a university in Tribhuvan, Nepal. Tribhuvan University (TU) is a pioneering higher education institution in Nepal, having been founded in 1959. ......

Pokhara University... Kathmandu University...

Purbanchal University is located in Purbanchal, India.

Lumbini Bauddha University (LBU) is a university in Lumbini, Nepal...

Nepal Sanskrit University is a university dedicated to the study of Sanskrit in Nepal.

Midwestern University is a public university in the Midwest...

Nepal Open University is a public university in Nepal.

Explanation:

Answer:

subscript is 3

Explanation:

the  subscript is the number that is slightly lower than a # which in this case it's O

this indicates that there's 3 oxygen atoms

Answer:

the answer is 1 ‍♀️

Explanation:

Answer:

0.188mol

Explanation:

Using the formula as follows:

mole = mass/molar mass

Molar mass of hypomanganous acid, H3MnO4 = 1(3) + 55 + 16(4)

= 3 + 55 + 64

= 122g/mol

Mass of H3MnO4 is given as 22.912 g

Hence;

moles = 22.912 ÷ 122

number of moles = 0.188mol

Answer:

Hey mate.......

Explanation:

This is ur answer......

Climate change has been a key factor in increasing the risk and extent of wildfires in the Western United States. Research shows that changes in climate create warmer, drier conditions. Increased drought, and a longer fire season are boosting these increases in wildfire risk. But global warming has changed some of the underlying variables that make wildfires more or less likely to occur every year. Warmer temperatures increase the likelihood that fires will burn more intensely. They also cause snow to melt sooner, and lead to drier soils, forests, and plants, which act as kindling.

Hope it helps!

Brainliest pls!

Follow me! :)

Given :

An aqueous solution of 30g of salt in 80g of water.

To Find :

The % mass of the salt.

Solution :

Mass percentage of the salt is given by :

[tex]Mass \ \% = \dfrac{Mass \ of \ salt}{Mass \ of \ salt + Mass \ of \ water}\\\\Mass \ \% = \dfrac{30}{30 + 80 }\times 100 \%\\\\Mass \ \% = 27.27\ \%[/tex]

Hence, this is the required solution.

**Check for proof photos at the bottom.**

**Answers are in bold.**

__________________________________________________________

A student places three ice cubes in a beaker and allows them to partially melt. If she measures the temperature of the water in the beaker, what will she most likely observe? Explain your answer.

She will see that the temperature of the water is 0 degrees Celsius and it stays at that temperature until all the ice cubes completely melt.

__________________________________________________________

Use the table on the right to calculate each required quantity. Record values to 3 significant digits.

First answer: 35.8 kJ

Second answer: 871 g

Third answer: Fe

__________________________________________________________

An iron sphere with a mass of 75.00 g is heated to a temperature of 385.0°C. It is then placed in a beaker containing 150.0 g H2O at 100.0°C.

First answer: 339 kJ

Second answer: 9.02  kJ

Third answer: No

__________________________________________________________

A sample of water has a mass of 100.0 g. Calculate the amount of heat required to change the sample from ice at –45.00°C to water vapor at 175.0°C. Relevant constant values are given to the right.

First answer: 325  kJ

Second answer: boiling the water

__________________________________________________________

Identify the correct description for each part labeled on the diagram.  

A: ✔ heating solid

B: ✔ melting

C: ✔ heating liquid

D: ✔ boiling

E: ✔ heating gas

F: ✔ melting point

G: ✔ boiling point

Where are the particles closest together?

✔ A

When ice partially melts, the surrounding water remains at 0° Celsius. This is because ice melting only involves the water molecules overcoming intermolecular forces, or forces holding molecules together. The water molecules themselves aren't increasing in kinetic energy when turning into liquid. Since temperature measures kinetic energy, the temperature in this case, remains at 0°.

To find how much energy it takes to cause a phase change in a substance, you must find the number of moles, and determine whether to use ΔHvap and ΔHfus. ΔHvap is used to show how much energy is involved in evaporation and condensation, and ΔHfus is the same but used for melting and freezing. To find number of moles of a given substance, use the formula: mass of given substance divided by atomic mass. Both numbers have to use the same mass unit. Then, multiply number of moles by ΔHvap or ΔHfus to get kJ.

In a heating curve graph, the flat lines represent no change in energy, or the phase changes. The steep lines are change in energy, which are either heating or cooling. The bottom line is a heating/cooling solid. A heating/cooling solid is the coldest phase, which is why the line is at the bottom.

Here are photos of Edge to make things easier.

Answer:

x = 2, [tex]CH_{4} + 2O_{2} = CO_{2} + 2H_{2}O\\[/tex]

Explanation:

This question is related to balancing chemical equations.

[tex]CH_{4} + xO_{2} = CO_{2} + 2H_{2}O\\[/tex]

- There must be the same amount of carbons (C), hydrogens (H), and oxygens (O) on each side of the equals sign.

- There is already 1 carbon and 4 hydrogens on each side of the equals sign. The big number in front of the chemical compound multiplies into the individual elements and can be multiplied by the subscripts to get the total number of each element.

- On the right side of the equation, there are 4 oxygens (O), and on the left side, there are 2. In order for there to be 4 oxygens (O) on the left side, there must be a 2 in front of [tex]O_{2}[/tex].

Therefore, x = 2.

[tex]CH_{4} + 2O_{2} = CO_{2} + 2H_{2}O\\[/tex]

Answer:

1.25 moles of magnesium chloride are produced

Explanation:

Based on the reaction:

Mg(s) + 2HCl (aq) → MgCl₂(s) + H₂(g)

1 mole of magnesium, Mg, reacts with 2 moles of hydrochloric acid, HCl, to produce 1 mole of magnesium chloride, MgCl₂ and 1 mole of hydrogen gas.

To solve this question we have to tak, from the chemical equation:

2 mol HCl = 1mol MgCl₂

That means, the moles of MgCl₂ produced from 2.50mol HCl are:

2.50 mol HCl * (1mol MgCl₂ / 2mol HCl) =

Answer:

289.8g

Explanation:

Using the formula as follows:

mole = mass/molar mass

Molar mass of SnF = 119 + 19

= 138g/mol

Using mole = mass/molar mass

2.1 = mass/138

mass = 2.1 × 138

mass = 289.8g

Answer:

(A) those with atomic numbers from 93 to 118

Explanation:

got the answer from q**zlet. hope this helps :)

Answer:

I probably think it's to achieve a higher energy state

Explanation:

-

Answer:

2.18 grams of Br2 reacts to produce 3.25 grams of KBr

Explanation:

The balanced equation is

2 KI + Br2 → 2 KBr + I2

2 moles of KI and 1 mole of Br2 reacts to produce two molecules of KBr

Mass of two moles of KI = 2 * 166 grams

Mass of one mole of Br2 = 159.808 grams

Mass of two moles of KBr = 2* 119 grams

Thus,  159.808 grams of Br2 reacts to produce 2* 119 grams of KBr

2.18 grams of Br2 reacts to produce {(2* 119)/ 159.808} * 2.18 grams of KBr

2.18 grams of Br2 reacts to produce 3.25 grams of KBr

Explanation:

moles= number of particle or atom / 6.02×10^23

so

[tex] \frac{1.1 \times {10}^{20 } }{6.02 \times {10}^{23} } [/tex]

gives u 1.83×10^-4 moles

hope it make sense :)

Answer:

1.7 * 10^-4 moles

Explanation:

According to Avogadro, one mole of a substance contains 6.02 * 10^23 number of atoms, molecules, ions etc.

Hence;

1 mole of Na contains 6.02 * 10^23 atoms

x moles of Na contains  1.0x10^20 atoms

x = 1.0x10^20 * 1/6.02 * 10^23

x = 1.7 * 10^-4 moles

An investigation is conducted into how the mass of magnesium metal reacting with hydrochloric acid affects the amount of hydrogen gas produced.

Masses of 0.10g, 0.20g, 0.30g and 0.40g of powdered Mg metal are reacted with hydrochloric acid(HCl). The conical flask containing the reaction mixture of Mg and HCl is connected to another conical flask with a hose. The hydrogen gas produced by the reaction is collected in this conical flask. The greater the amount of hydrogen gas produced by the reaction the greater the pressure of the gas in the flask.

Answer:

A) what is the independent variable:

B) what is the dependent variable:

C) write a hypothesis for this investigation:

D) give 2 variables that should have been controlled for this investigation:

Answer:

103.98 kpa

Explanation:

Pv= nRT

Where

P= pressure of the system=

n= number of moles= 3 moles

T= temperature= 250 K

Volume of the container= 60 liters

R= 0.0821L.atm/K.mol

Substitute the values

Pv= nRT

P= nRT/ V

= (3×0.0821×250)/60

= 1.026 Atm

1atm= 101325 Pascal

1.026 atm= X

= 103984 pasca

Convert to kilopascal

= 103984 pasca /1000

= 103.98 kpascal