what is the mass of 1.5 x 10^21 silicon atoms?

Answer:

true

Explanation:

Answer:D

Explanation:

The majority of explosives that forensic scientists deal with in investigations are homemade bombs. Therefore, option D is correct.

In general, forensic scientists do the following kinds of work: They examine tangible materials gathered from crime sites. They offer forensic expert testimony both before and during court proceedings. Blood, hair, and other trace evidence are gathered by investigators and sent to crime labs for analysis.

Criminalists or crime scene investigators are generalist forensic science technicians that gather evidence at the scene of a crime and conduct scientific and technical examination in labs or offices.

A forensic scientist's key responsibilities include gathering evidence at the crime scene, documenting the findings in reports, processing the evidence at the lab, and giving testimony in court.

Thus, option D is correct.

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The property of water that is not critical to biological life is surface tension.

Biological life means the life in which living organism do exist and for their survival they mainly depends on water and air.

The main critical properties that water should posses to biological life are density, temperature, cohesive force and adhesive force. Viscosity is also understand by the cohesive force because more attraction between atoms more viscous they are.

Hence option (1) is correct i.e. surface tension.

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Answer:

Nuclear reactions involve a change in an atom's nucleus, usually producing a different element. Chemical reactions, on the other hand, involve only a rearrangement of electrons and do not involve changes in the nuclear.

Answer:

62 grams

Explanation:

Molarity=mol/liter

We have mL and Molarity

500 mL * 1 L/1000 mL=0.5

Plug 0.5 in and solve for moles

0.75=mol/0.5

0.75*0.5=0.375 mol

Convert to grams by finding the mass of KI: 39+126.9= 165.9 grams

0.375 mol KI * 165.9 grams KI/1 mol KI= 62.2125 grams

The mass of KI needed is 124.5 grams, this can be calculated by adding the values in molarity formula.

It is defined as number of moles of solute over volume of solution in liters.

It is given by:

M = n/ V

What information do we have?

Molarity= 0.750 M

Volume = 500 mL= 1 L

Molar mass of KI = 166 g/mol

To find:

Mass of KI=?

On substituting the values:

M= n/V

0.750 M= n/ 1 L

n= 0.750 M* 1l

n= 0.750 moles

Number of moles is the ratio between mass and molar mass.

n= m/M

0.750 moles = m/ 166 g/mol

m= 0.750*166

m= 124.5 grams.

Thus, the mass of KI needed is 124.5 grams.

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Answer:

I think the answer will be number A

The boiling point of a substance is constant and for water it is 100 degree celsius. However by reducing the surrounding pressure the boiling point can be reduced.

Boiling point of a substances is the temperature at which the vapor pressure of the gas phase above the liquid equals to the atmospheric pressure where, the liquid converts to the vapor state.

Boiling point depends on the bond type, molar mass, temperature and pressure. As the and pressure increases, boiling point increases. Similarly with an increasing mass and more strength intermolecular force results in greater boiling point.

As the atmospheric pressure decreases, the temperature needed to equalise the vapor pressure of the gas phase over the liquid also decreases. Hence, boiling point decreases. Therefore, option C is correct.

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Explanation:

In chemistry, an ionic compound is a chemical compound composed of ions held together by electrostatic forces termed ionic bonding. The compound is neutral overall, but consists of positively charged ions called cations and negatively charged ions called anions.

Answer:

because it may cause burn that causes acid to build up which causes you to keep having an upset stomach

Answer:

Eqv Pt pH = 8.73

Explanation:

    HOAc                   +            NaOH            =>            NaOAc              + H₂O

50ml(0.10M HOAc)  +  50ml(0.10M NaOH) => 100ml(0.05M NaOAc) + H₂O

For neutralized system, 100ml of 0.05M NaOAc remains

NaOAc => Na⁺ + OAc⁻

Na⁺ + H₂O => No Rxn

          OAc⁻  +  H₂O  => HOAc + OH⁻

C(i)   0.05M       -----        0M      0M

ΔC        -x           -----         +x        +x

C(f)    0.05-x      

       ≅ 0.05M    -----          x          x

Kb = Kw/Ka = [HOAc][OH⁻]/[OAc⁻] = 1 X 10⁻¹⁴/1.7 X 10⁻⁵ = (x)(x)/(0.05M)

=> x = [OH⁻] = SqrRt(0.05 x 10⁻¹⁴/1.7 x 10⁻⁵) = 5.42 x 10⁻⁶M

=> pOH = -log[OH⁻] = -log(5.42 x 10⁻⁶) = 5.27

pH + pOH = 14 => pH = 14 - pOH = 14 - 5.27 = 8.73 Eqv Pt pH

Salts with nitrates as the anion are generally soluble in water. The question isn’t quite clear: Are we being asked what precipitate would form if these solutions were mixed together? If that’s the case, the reaction would be as follows:

Li3AsO4(aq)+ Fe(NO3)3(aq) → 3LiNO3(aq) + FeAsO4(s).

It is odd that we’re given lithium arsenate dissolved in water to begin with as lithium arsenate should be insoluble. But assuming that it is water-soluble, we can obtain the net ionic equation for the formation of our precipitate:

Fe3+(aq) + [AsO4]3-(aq) → FeAsO4(s).

Our precipitate would be iron(iii) arsenate, FeAsO4.

Answer:

At D: Soil erosion us the process taking place.

Soil erosion is the washing away of the Earth's or soil's top layer by eroding agents.

Answer:

Look below

Explanation:

Nitrogen: N

Phosphorus: P

Bromine: Br

Zinc: Zn

Potassium: K

Magnesium: Mg

Hope this helps(would be very grateful if you mark this answer branliest bc i need for lvl up)

Answer:

1. Distance  = 5 cm

Displacement = 1 cm

2. Distance = 7 cm

Displacement = 1 cm

3. Distance = 5 cm

Displacement = -1 cm

4. Distance  = 6 cm

Displacement = -2 cm

5. Distance  = 4 cm

Displacement = 0 cm

Explanation:

The distance an object travels is a measure of the total ground cobpvered bybthe object without regard to the direction of motion. It is a scalar quantity as it only takes into account magnitude but not the direction of a quantity.

Displacement however, is a measure of how far away or apart an object is from its starting position.  It a vector quantity as it takes into account both the magnitude and direction in its measurement.

From the attachment provided, considering forward direction as positive and reverse as negative :

1. When a object moves from point 1 to point 4 and reverses to point 2.:

Distance  = from 1 to 4 = 3 cm; from 4 back to 2 = 2 cm;  3 + 2 = 5 cm

Displacement = from 1 to 4 = +3 cm; from 4 back to 2 = -2 cm;  3 - 2 = 1 cm

2. When an object moves from point 1 to 5 and reverses to 2:

Distance = from 1 to 5 = 4cm; from 5 back to 2 = 3 cm; 4 + 3 = 7 cm

Displacement = from 1 to 5 = +4 cm; from 5 back to 2 = -4 cm;  4 - 3 = 1 cm

3. When an object moves from point 1 to 3 and then reverses to 0.

Distance  = from 1 to 3 = 2 cm; from 3 back to 0 = 3 cm;  2 + 3 = 5 cm

Displacement = from 1 to 3 = +2 cm; from 3 back to 0 = -3 cm;  2 - 3 = -1 cm

4. When an object moves from point 3 to 5 and then reverses to 1:

Distance  = from 3 to 5 = 2 cm; from 5 back to 1 = 4 cm;  2 + 4 = 6 cm

Displacement = from 3 to 5 = +2 cm; from 5 back to 1 = -4 cm;  2 - 4 = -2 cm

5. When an object moves from point 2 to 4 and then reverses to 3.

Distance  = from 2 to 4 = 2 cm; from 4 back to 2 = 2 cm;  2 + 2 = 4 cm

Displacement = from 2 to 4 = +2 cm; from 4 back to 2 = -2 cm;  2 - 2 = 0 cm

Answer:

a variable (often denoted by x ) whose variation does not depend on that of another.

Explanation:

You can think of independent and dependent variables in terms of cause and effect: an independent variable is the variable you think is the cause, while a dependent variable is the effect. In an experiment, you manipulate the independent variable and measure the outcome in the dependent variable.For example, someone's age might be an independent variable. Other factors (such as what they eat, how much they go to school, how much television they watch) aren't going to change a person's age.

Answer:

The balanced equation would be 2H2 + O2 -> 2H2O

Explanation:

The correct balanced equation is 2H₂ + O₂  →  2H₂O, and  the correct coefficient for O₂ is 1.

Count the atoms on each side first. Next, alter one of the compounds' coefficient. Third, count the atoms once more, and then repeat steps two and three until the equation is balanced.

In the given equation, hydrogens are already balanced. To balance oxygen, multiple water with 2. Thus, equation becomes:

H₂  + O₂  →  2 H₂O

Now, oxygen is balanced, just the hydrogens got unbalanced. To balance hydrogen, multiply the hydrogen by 2 on the left side.

2 H₂ + O₂  → 2H₂O

Now the chemical equation is balanced, in which the number of oxygen and hydrogen are equal on both sides of the arrow.

Therefore, the coefficient of O₂ is 1.

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Answer:

Alveoli

Explanation:

I hope this helps you.

Answer:

2890j

Explanation:

Answer:

25.9g

Explanation:

Molecular mass of Fe₂O₃ = (56 * 2) + (16 * 3)

                                          = 112 + 48 = 160

Let's follow the unitary method now

In 160g Fe₂O₃ , there is 112 g Fe

In 1 g  Fe₂O₃ , there is 112 / 160 g Fe

In 37  Fe₂O₃ , we need 112 * 37 / 160

= 25.9 g Fe

Answer: If the solubility of sodium chloride is 36 grams per 100 grams of water then 5.8 moles of NaCl dissolved in 1 L of water solution would be considered unsaturated.

Explanation:

A solution which contains the maximum amount of solute is called a saturated solution. Whereas a solution in which more amount of solute is able to dissolve is called an unsaturated solution.

Now, the number of moles present in 36 g of NaCl (molar mass = 58.4 g/mol) is as follows.

[tex]No. of moles = \frac{mass}{molar mass}\\= \frac{36 g}{58.4 g/mol}\\= 0.616 mol[/tex]

This shows that solubility of sodium chloride is 36 grams per 100 grams of water means a maximum of 0.616 mol of NaCl will dissolve in 100 mL of water.

So, a solution in which number of moles of NaCl are less than 0.616 mol per 100 mL then the solution formed will be an unsaturated solution.

[tex]Moles = \frac{5.8 mol}{1000 mL} \times 100 mL\\= 0.58 mol[/tex]

[tex]Moles = \frac{3.25 mol}{500 mL} \times 100 mL\\0.65 mol[/tex]

[tex]Moles = \frac{1.85 mol}{300 mL} \times 100 mL\\= 0.616 mol[/tex]

Thus, we can conclude that if the solubility of sodium chloride is 36 grams per 100 grams of water then 5.8 moles of NaCl dissolved in 1 L of water solution would be considered unsaturated.

Answer:

The chloride ion has no effect on the acidity of the solution since HCl is a strong acid. Chloride is a very weak base and will not accept a proton to a measurable extent. However, the ammonium ion, the conjugate acid of ammonia, reacts with water and increases the hydronium ion concentration:

Explanation:

Answer:

7. Convection

8. Radiation

9. Conduction

Explanation:

Convection is when a fluid, such as air or a liquid, is heated and then travels away from the source, it carries the thermal energy along.

Radiation is the energy that is emitted by matter in the form of photons or electromagnetic waves. So, it is coming off the fire which makes it radiation.

Conduction is the process by which heat or electricity is directly transmitted through a substance when there is a difference of temperature or of electrical potential between adjoining regions, without movement of the material. Because the picture shows different temperatures, it leds to the conclusion that 9 is conduction.

I hope this helps!!

Answer:

6.1

Explanation:

From the question given above, the following data were obtained:

Hydrogen ion concentration [H⁺] = 8.2×10¯⁷ M

pH =?

The pH of the solution can be obtained as follow:

pH = –Log [H⁺]

pH = –Log 8.2×10¯⁷

pH = 6.1

Thus, the pH of the solution is 6.1

Answer:

1.77 * 10^-3

Explanation:

From the titration formula;

Let

CA = concentration of acid

CB = concentration of base

VA = volume of acid

VB = volume of base

NA = number of moles of acid

NB = number of moles of base

The equation of the reaction is;

M(OH)2(aq) + 2HCl(aq) -------> MCl2(aq) + 2H2O(l)

So;

CAVA/CBVB= NA/NB

CAVANB = CBVBNA

CB= CAVANB/VBNA

CB= 0.173 * 25.10 * 1/28.5 * 2

CB= 4.3423/57

CB= 0.0762 M

This implies that the solubility of M(OH)2 = 0.0762 M

M(OH)2(s) ----> M^+(aq) + 2OH^-(aq)

So

Ksp = x * (2x)^2

Ksp = 4x^3

x = 0.0762

Ksp= 4(0.0762)^3

Ksp = 1.77 * 10^-3

Answer:

10.66  grams

Explanation:

Answer:

The answer is streak (A)

Because Streak (the colour of a mineral in its powdered form) is usually obtained by rubbing the mineral on a hard, white surface, such as a tile of unglazed porcelain, so as to yield a line, or streak, of fine powder.

Answer: True because if you leave it outside and it rains on the bike it will cause rust. Keep it in the garage or something. :) I have a bike btw.

Explanation:

The best way to prevent rusting is to store your bike safely away when it isn't being used and apply a rust-proofing lubricant to protect it when you are riding it – enjoying those wet and wild rides guilt-free!

so true

Answer:

The answers to your questions are given below

Explanation:

F. Determination of the missing part of the equation.

_ I₂ + _Na₂S₂O₃ —> _ NaI + _ Na₂S₄O₆

The above equation can be balance as illustrated below:

I₂ + Na₂S₂O₃ —> NaI + Na₂S₄O₆

There are 2 atoms of I on the left side and 1 on the right side. It can be balance by writing 2 before NaI as shown below:

I₂ + Na₂S₂O₃ —> 2NaI + Na₂S₄O₆

There are 2 atoms of Na on the left side and a total of 4 atoms on the right side. It can be balance by writing 2 before Na₂S₂O₃ as shown below:

I₂ + 2Na₂S₂O₃ —> 2NaI + Na₂S₄O₆

Now the equation is balanced.

The coefficients are: 1, 2, 2, 1

Elements >>> Reactant >>> Product

Sodium >>>>> 4 >>>>>>>>> 4

Sulphur >>>>> 4 >>>>>>>>> 4

Oxygen >>>>> 6 >>>>>>>>> 6

Iodine >>>>>> 2 >>>>>>>>>> 2

G. Determination of the missing part of the equation.

__ Mg + __P₄ —> __Mg₃P₂

The above equation can be balance as illustrated below:

Mg + P₄ —> Mg₃P₂

There are 2 atoms of P on the right side and 4 atoms on the left side. It can be balance by writing 2 before Mg₃P₂ as shown below:

Mg + P₄ —> 2Mg₃P₂

There are 6 atoms of Mg on the right side and 1 atom on the left side. It can be balance by writing 6 before Mg as shown below:

6Mg + P₄ —> 2Mg₃P₂

Now the equation is balanced.

The coefficients are: 6, 1, 2

Elements >>>> Reactant >>> Product

Magnesium >> 6 >>>>>>>>> 6

Phosphorus >> 4 >>>>>>>>> 4