Question 1 (2 points)
Which option can be classified as a pure substance?

Question 1 options:

heterogenous mixture


solution


homogenous mixture


compound

Question 2 (2 points)
Law of conservation of mass states that:

Question 2 options:

matter is destroyed


matter does not change


matter is neither created nor destroyed


matter is created

Question 3 (2 points)
What is a property of bases?

Question 3 options:

all of the above


Sour taste


Slippery touch


Ability to form hydronium ions+

Question 4 (2 points)
Which property do solutions with low pH values have?


What does it mean to have a neutral pH? - Aseptic Health

Question 4 options:

have a -OH group


feels slippery


turns litmus paper blue


tastes sour

Question 5 (2 points)
How do the products of chemical reactions compare to their reactants?

Question 5 options:

The products often have completely different properties than the reactants.


The products are usually more toxic than the reactants.


The products usuallyhave more mass than the reactants.


The products usually have more atoms than the reactants.

Question 6 (2 points)
Which of the following is an example of a physical change?

Question 6 options:

Water freezing into ice.


A piece of wood burning.


A toy car rusting.


Zinc producing hydrogen gas when mixed with water.

Question 7 (2 points)
What might happen if you mixed a strong acid with an equally strong base?

Question 7 options:

You would see an explosive chemical reaction.


The base would destroy the acid.


You'd wind up with a pH-neutral salt and water.


The acid would destroy the base.

Question 8 (2 points)
In the equation shown, what are the reactants?

2H2+O2àH2O

Question 8 options:

Hydrogen and oxygen molecules (2H2 and O2 )


Ice crystals


Hydrogen atoms (H)


Water molecules (H2O)

Question 9 (2 points)
Which phrase most accurately describes a chemical change?

Question 9 options:

A change in form


A change in taste


A change on the molecular level


A change in appearance

Question 10 (2 points)
What does it mean when there is a physical change?

Question 10 options:

A new substance has been formed.


Matter has changed from one substance into a new substance.


Matter has changed size, shape or form


Matter has changed on the molecular level.

help pls ill give 20 points!

Answer:

inclined plane, a simple machine consisting of a sloping surface, used for raising heavy bodies. The force required to move an object up the incline is less than the weight being raised, discounting friction

Explanation:

The steeper the slope, or incline, the more nearly the required force approaches the actual weight. The steeper the slope, or incline, the more nearly the required force approaches the actual weight.

Answer:

C

Explanation:

Bad , fad is the answer check

Answer:

4 enzymes responsible for digestion:

1. Salivary amylase ---- substrate: Starch ---- end-product: Maltose  

2. Lipase  ---- substrate: Lipids (fats and oils) ---- end-product: Fatty acids and glycerol

3. Maltase ---- substrate: Maltose ---- end-product: Glucose

4. Protease ---- substrate: Protein ---- end-product: Amino acids

Answer:

4.6 grams CuCl2

Explanation:

Since molarity is a representation of moles per liter, we first want to convert 450. mL to liters:

450. mL * 1 L/1000 mL = 0.450 L

Now, we can use this number and the molarity to figure out the answer:

0.075 M means that for every liter, there is 0.075 moles of CuCl2.  Thus, we can multiply the amount of moles per liter by the number of liters of solution.

0.075 moles/1 L * 0.450 L = 0.03375 moles

Then, we need to round this to the appropriate number of significant figures, which gives us:  

0.034 moles CuCl2

Next, we can find the grams of CuCl2.  To do this, we first need to find the molar mass of CuCl2.  The molar mass of Cu is 63.546 g/mol and the molar mass of Cl is 35.453 g/mol, so the molar mass of CuCl2 is as follows:

(1 Cu * 63.546) + (2 Cl * 35.453) = 134.45 g/mol CuCl2

Now, we can multiply the grams per mole by the number of moles of CuCl2 in our solution:

134.45 g/mol * 0.034 moles = 4.5713 grams = 4.6 grams CuCl2, rounded to the appropriate significant figures.

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Blank # 1 - keep safe distance from the burner

Blank # 2 - Place the equipments on the right place after use

Blank # 3 - perform experiments with proper lab equipment and safety tools

Blank # 4 - Don't break any test tube or lab equipment

(maybe it can be hazardous)

Answer:

1. weak acid

2. weak base

3. weak acid

4. neutral

5. acidic

6. weak base

Explanation:

You can use a pH level scale like the one I attached, to determine each solution.

Answer:

digestion

Explanation:

Answer:

Electrical Bonding Investigation Data Quick Check

Explanation:

B. Heat energy is added to the substance, weakening the electrica attraction between molecules.

C. Both the melting point and boiling point are lower

C. The lone pairs of electrons in the oxygen atom causes the molecule to be bent; the oxygen atom has a particle negative charge, while the hydrogen atom have particle positive charges

D. Phase change

C. At each plateau

Answer:

The answer is the first one.

Explanation:

The lower a pH level the higher the the number hydrogen ions present in the acid's container.

ph = - log(H)

4 = - log(H)

- 4 = log(h)

10^-4 = H+

1 * 10^-4 = H +

ph = - log(H)

ph = 2

- 2 = log(H)

10^-2 = H

1*10^-2 = h

Something the power - 2 is 100 times greater than something with the power of -4

Answer:

the guy above is correct

Explanation:

Answer:

The Brazilian Santos Dumont

Explanation:

Santos Dumont created the 14 Bis airplane, the first airplane to perform a flight through 200 meters im Paris, France, in 23 October 1906

Orville and Wilbur Wright were the first two to actually invent the aeroplane. These American brothers also designed and flew their first creation after making it in their bicycle shop in December 17, 1903.

I hope this helps! :)

Answer:

its the movement because kinetic energy means moving not stopping or decreasing

Explanation:

Answer:

Graphite and diamond are two of the most interesting minerals. They are identical chemically – both are composed of carbon (C), but physically, they are very different. Minerals that have the same chemistry but different crystal structures are called polymorphs.

it is a 0 degrees on the Kelvin scale

it is also the lowest on the thermometer

also the particles stop moving and all disorder disappears.

Answer:

(iii):

Reaction 1: Addition

[ We added chlorine to 2-propene ]

Reaction 2: Substitution

[ We substituted hydroxyl ion with chloride ion ]

Reaction 3: Oxidation

[ Acidified permanganate solution is a strong oxidizing agent. So we oxidized propanol to propanoic acid ]

Reaction 4: Acid - base

[ A base (Sodium hydroxide) is added to an acid (propanoic acid) to form a neutral salt ( Sodium propanoate ) ]

Considering the definition of ideal gas law, the volume of the Krypton gas is 3840 mL.

An ideal gas is a theoretical gas that is considered to be composed of point particles that move randomly and do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.

The pressure, P, the temperature, T, and the volume, V, of an ideal gas, are related by a simple formula called the ideal gas law:  

P×V = n×R×T

where P is the gas pressure, V is the volume that occupies, T is its temperature, R is the ideal gas constant, and n is the number of moles of the gas. The universal constant of ideal gases R has the same value for all gaseous substances.

Now, taking into account this law, and isolating the pressure variable (P), you get:

[tex]V=\frac{nxRxT}{P}[/tex]

In this case, you know:

Replacing in the ideal gas law:

[tex]V=\frac{0.119 molesx0.082 \frac{atmL}{moleK}x298K}{0.756579 atm}[/tex]

Solving:

V=3.84 L= 3840 mL (being 1 L=1000 mL)

Finally, the volume of the Krypton gas is 3840 mL.

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Answer:

Ans B)=====> Dorsal Horn

Two arms, each known as a Dorsal Horn, are formed by the core grey matter at the back of the spinal cord. In the image, the region labeled “ A “ is called the Dorsal Horn. Therefore, option B is correct.

One of the gray longitudinal columns discovered inside the spinal cord is the dorsal horn. Through the dorsal roots of the spinal nerves, it predominantly serves as the end of primary afferent fibers.

A complex network of excitatory and inhibitory interneurons, as well as projection neurons, make up the dorsal horn, which serves as an intermediary processing center for this information. It transmits the processed somatosensory information from the spinal cord to the brain.

The cell bodies of sensory neurons are located in the dorsal horns. The ventral horns are two arms of central grey matter that are found at the front of the spinal cord.

Thus, option B is correct.

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D or A im not fully sure about my answer on that

The molality of the solution is 1.4 moles per kilogram (molal).

The molality of the solution is equal to the number of moles of sugar (solute) divided by the number of kilograms of water (solvent). Hence, the molality is determined below:

[tex]m = \frac{3.5\,mol}{2.5\,kg}[/tex]

[tex]m = 1.4\,\frac{mol}{kg}[/tex]

The molality of the solution is 1.4 moles per kilogram (molal).

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Answer:

Because there is no water and they restore their food.

Explanation:

Like their glucose and that's why they also the leaf changes color

Answer:

Explanation:

Octane

Octane is a straight chain alkane composed of 8 carbon atoms.

Answer:

Refer to the periodic table to do this.

Explanation:

1. Na, K, Cs Fr, Rb

  Sodium, Potassium, Cesium, Francium, Rubidium

  3, 4, 6, 7, 5

Ascending order: Na, K, Rb, Cs, Fr

2. Ca, Sr, Ba, Ra, Mg

   Calcium, Strontium, Barium, Radium, Magnesium

   4, 5, 6, 7, 3

Ascending Order: Mg, Ca, Sr, Ba, Ra

When doing the electronic configuration of the elements, count how many number of divides it has. For example, Na(Sodium) has 11 electrons and it is divided like this: 2,8,1. So it divides into 3 parts so there will 3 shells for sodium.

Hopefully this helps!!

Answer:

yes because on the left side 4 hydrogen in right side 4 hydrogen on the left side 2 oxygen in the right side 2 oxygen

Answer:

The Law of Conservation of Mass states that the mass of the system must remain constant over time as the system's mass cannot change because energy is not created nor destroyed. To tell if a chemical equation meets this law, check to see if the number of atoms is the same on both sides of the chemical equation.

Reactant Side:

Product Side:

Remember, when counting the atoms in a equation the subscript is the number that represents the quantity of that specific atom. Subscripts are numbers that come after a symbol and below. If an element does not have a subscript, then it is understood that the subscript is 1.  The coefficent represents the quantity of molecules, the coefficient multiplies everything in the formula.

Answer:

with in one to two days of

Answer:

Can u phrase differently?

Answer:

If you are looking for the formula, then it is NaOCl

Explanation:

The molecular mass (molar mass) of this gas is equal to 44.08 g/mol.

Given the following data:

To calculate the molecular mass (molar mass) of this gas, we would use the ideal gas law equation;

[tex]PV=\frac{MRT}{MM}[/tex]

Where;

Making MM the subject of formula, we have:

[tex]MM = \frac{MRT}{PV} \\\\MM = \frac{23.6\times 0.0821 \times 273}{1 \times 12}\\\\MM = \frac{528.95}{12}[/tex]

Molar mass, MM = 44.08 g/mol.

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Explanation:

Mass ratio C : H : N = 27.3 : 9.10 : 63.6

Mole ratio C : H : N = 27.3/12: 9.10/1 : 63.6/14

( Divide the mass ratio by their molar masses to find the ratio between moles)

Mole ratio = 2.275 : 9.10 : 4.54

= 2.275/2.275 : 9.10/2.275 : 4.54/2.275

= 1 : 4 : 2

Answer is CH4N2

The empirical formula of a compound is [tex]CH_4N_2[/tex]

The empirical formula of a chemical compound is defined as the simplest whole number ratio of the atoms present in a compound.

The empirical formula of a compound defines the simplest ratio of the number of different atoms present. The molecular formula gives the actual number of each different atom present in a molecule. The molecular formula is mainly used which is a multiple of the empirical formula.

Molecular Formula  = n × Empirical Formula

For above given example,

Mass ratio C : H : N = 27.3 : 9.10 : 63.6

Mole ratio C : H : N = 27.3/12: 9.10/1 : 63.6/14

( We divide the mass ratio by their molar masses to find the ratio between moles)

Mole ratio = 2.275 : 9.10 : 4.54 = 2.275/2.275 : 9.10/2.275 : 4.54/2.275

= 1 : 4 : 2

Thus, the empirical formula of a compound is [tex]CH_4N_2[/tex]

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