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1. The atomic number tells us how many ____________ an element has.

protons

neutrons

electrons

Answer:

Lead(II) acetate trihydrate

Explanation:

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Answer:

H20

Explanation:

. It is a symbol of water where H = Hydrogen, O = Oxygen and2 Elements in hydrogen and 1 element in oxygen;therefore its known as H2O.

H2O is chemical symbol describes an element.

The chemical symbol is a representation of the name of the chemical element which is discovered and expressed in the periodic table, a type of matter that is classified by the atomic number.

The periodic table the chemical elements are present according to their atomic number, electron configuration, and chemical properties.

It help everyone from different language background and used in identification of  the element according to the universal  chemical symbol, some symbols are H for hydrogen, Cu for copper.

Chemical symbols also applied in case of certain elements which make up the matter like water  is made up of two molecules of hydrogen and 1 of oxygen, which is represented with the chemical symbol of H2O.

The chemical element is made up of atoms which have the same number of protons called the atomic number, simplest form of a substance and contains one class of atoms.

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Answer:

d mushrooms

Explanation:

The arrows on a food web point to where the energy source goes. Although mushrooms are considered decomposers, all the energy ends up at the mushroom and that is what makes a primary consumer the primary consumer no matter what.

ANSWER:

The answer is GRASSHOPPER

EXPLANATION:

Organisms feed on one another to obtain energy needed for metabolic activities. Food web is one of the ways by which the relationship between these organisms that feed on one another is displayed.

Energy flow starts from a PRODUCER, which is the plant in this food web. An organism (usually an herbivore) that feeds on the producer is referred to as PRIMARY CONSUMER. All consumers are incapable of synthesizing their own food, hence, they depend on other organisms. However, primary consumers directly depend on producers.

In the food web attached to this question as an image, the PRIMARY CONSUMER is the GRASSHOPPER because it directly feeds on the PRODUCER (plant).

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Answer:

noble gases

Explanation:

Group 8A — The Noble or Inert Gases. Group 8A (or VIIIA) of the periodic table are the noble gases or inert gases: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). The name comes from the fact that these elements are virtually unreactive towards other elements or compounds.

Answer:

noble gases

Explanation:

Gathering 8A — The Noble or Inert Gases. Gathering 8A (or VIIIA) of the intermittent table are the respectable gases or dormant gases: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). The name originates from the way that these components are practically lifeless towards different components or mixes.

Answer:

a

Explanation:

N2 means that each nitrogen atom is bonded to another and they act as a unit. 2N means that each nitrogen atom is separate from the other. So the correct options are B and D.

The chemical element nitrogen has an atomic number of seven (it has seven protons in its nucleus). Two nitrogen atoms are securely linked together to form the chemical molecule known as molecular nitrogen (N2). At normal temperatures and pressures, molecular nitrogen is a colorless, odorless, tasteless, and inert gas.

Nitrogen makes up around 78% of the Earth's atmosphere. Molecular nitrogen is a molecule that is practically inert due to the strong triple bond that connects its atoms. But when nitrogen bonds do break, the ensuing substances are frequently quite reactive.

Numerous different forms of contaminants include atoms of nitrogen. Nitric oxide (NO) and nitrogen dioxide can be produced during high-temperature combustion when nitrogen gas is present, such as in car engines (NO2). Both gases contribute to the creation of nitric acid, which is a component of acid rain, and peroxyacetyl nitrate (PAN), which is a key component of smog. They are both toxic on their own.

Therefore the correct options are B and D.

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Answer:

c. alcohol oxidation

Explanation:

The police often use a device called a breathalyzer to test drivers suspected of being drunk. The chemical basis of this device is a redox reaction. A sample of the driver’s breath is drawn into the breathalyzer, where it is treated with an acidic solution of potassium dichromate. The alcohol (ethanol) in the breath is  converted to acetic acid as shown in the following equation:

3 CH₃CH₂OH + 2 K₂Cr₂O₇ + 8H₂SO₄   → 3 CH₃COOH + 2 Cr₂(SO₄)₃ + 2 K₂SO₄ +1 11H₂O

ethanol + potassium dichromate (orange yellow)  + sulfuric acid → acetic acid +  chromium(III) sulfate (green) + potassium sulfate + water

In this reaction, the ethanol is oxidized to acetic acid and the chromium(VI) in the orange-yellow dichromate ion is reduced to the green chromium(III) ion. The driver's blood alcohol level can be determined readily by measuring the degree of this color change (read from a calibrated meter on the instrument).

Answer:

3. Physical properties can be observed and chemical properties can't

Explanation:

a. 1 nm = 10Å

683nm=683×10Å

=6830 Å

b. 1 mi/h=0.44704

520 mi/h=520×0.44704

=232.4608

c. 1 g/cm3=62.427961 lb/ft3

0.714 g/cm3=0.714×62.427961 lb/ft3

=44.573564

d. 1°C =9/5 +32 =33.8°F

-164°C = -164×9/5+32 = -263.2°F

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Answer:

Uncertainty of tolerance transfer pipet  = ± 0.15

Volume of liquid between =  149.85, 150.15

Given:

Size of transfer pipet = 50 ml

Tolerance transfer pipet = ± 0.05 ml

Total transfer = 150 ml

Find:

Uncertainty of tolerance transfer pipet

Computation:

Uncertainty of tolerance transfer pipet  = [150 / 50](± 0.05)

Uncertainty of tolerance transfer pipet  = [3](± 0.05)

Uncertainty of tolerance transfer pipet  = ± 0.15

Volume of liquid between = (150-0.15), (150+0.15)

Volume of liquid between =  149.85, 150.15

They contain Carbon, Nitrogen, Hydrogen, Oxygen, and Sulfur

Answer: Since one molecule of CO2 contains one molecule carbon atoms, therefore, 0.6 molecule of carbon dioxide will contain 0.6 molecule of carbon.

Mass of C in 0.6 molecule of CO2

Explanation

= No. Of molecule × molar mass

= 0.6× 12gm

=7.2gm

Explanation:

Ionization energy refers to the minimum amount of energy required to remove the valence electron of an isolated neutral gaseous atom or molecule. Generally, ionization energy increases from left to right across the periodic table.

This means that the ionization energy of Carbon would be smaller than that of Fluorine. The reason for this is due to the smaller effective nuclear charge.

The effective nuclear charge and the atomic size are two factors that ionization energy depends on.

The correct option is;

IV. The effective nuclear charge of carbon is smaller, so the valence electrons feel a weaker pull from the nucleus.

Answer:

No

It's called a formula of an element which is a sodium element.

Answer:

[tex]1.09nL[/tex]

Explanation:

Hello,

In this case, given that 1 gal equals 4 qt, 1 qt equals 0.9464 L and 1 L equals 1x10⁹ nL, the dimensional analysis turns out:

[tex]2.87x10^{-10}gal*\frac{4qt}{1gal} *\frac{0.9464L}{1qt}*\frac{1x10^9nL}{1L}\\ \\1.09nL[/tex]

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Answer:

mercury, venus, mars, earth,  jupiter, saturn, uranus, neptune

Explanation:

Answer:

Mercury,Venus,Mars,Earth,Jupiter,Saturn,

Uranus,Neptune.

Explanation:

Hope this helps

Answer:

The mass percentage of chlorine in the original compound is 56.32%

Explanation:

From the question,

Mass of original compound = 0.4066 g

To, determine the mass percentage of chlorine in the original compound,

First, we will determine the mass of chlorine present in the precipitated AgCl

Mass of precipitated AgCl = 0.9260 g

Molar mass of AgCl

Ag = 107.87 g/mol; Cl = 35.45 g/mol

Then, molar mass of AgCl = 107.87  + 35.45

= 143.32 g/mol

Now,

If 35.45 g of chlorine is present in 143.32 g of AgCl

Then, [tex]x[/tex] g of chlorine will be present in 0.9260 g of AgCl

[tex]x = \frac{35.45 \times 0.9260}{143.32}[/tex]

[tex]x = 0.2290[/tex] g

Hence, 0.2290 g of chlorine is present in 0.9260 g of AgCl.

Since all of the chloride ion is precipitated,

then 0.2290 g of chlorine is present in the original chloride compound.

Now, for the mass percentage of chlorine in the original compound,

mass percentage of chlorine =

(mass of chlorine in the compound /mass of the chloride compound) × 100%

mass of chlorine in the compound = 0.2290 g

mass of the chloride compound = 0.4066 g

∴ mass percentage of chlorine = [tex]\frac{0.2290}{0.4066}[/tex] × 100%

mass percentage of chlorine = 56.32%

Hence, the mass percentage of chlorine in the original compound is 56.32%

Answer:

The answer is alkali metals

Explanation:

Answer:

C. Solids

Particles are closely packed in solids and have less kinetic energy.

Answer:

Sociologist view that an individual is a reflection of a society to which he or she have belonged.

Explanation:

It is not an individual or a society, but both of them together allows us to reveal the fundamentals of human existence. The extreme view of the person or society has been discarded for quite some time. The concept of society indicates a reciprocal giving-and-take by the individuals involved in the form of mutual corporations, interaction, or the more subtle types of social interaction such as letter writing, festival greeting, sending and accepting presents, telephone communication, e-mailing, internet chatting, and public relations engagement.

Answer:

47.871 amu

Explanation:

Average atomic mass of an atom is obtained from the sum of the mass of the isotopes multiplicated by its natural abundance.

That means atomic mass of Ti is:

Ti = 45.953*8.00% + 46.952*7.80% + 47.947*73.40% + 48.948*5.50% + 49.945*5.30%

Average atomic mass of Ti:

Answer:

b. Disulfide bond

Explanation:

Covalent linkage or bonding is a type of bond in which electrons are shared between atoms in a compound or molecule. Each atom contributes to the shared electron.

This is the case of disulfide bonding i.e. S-S, in which two thiol groups (-SH) share electrons with one another. The process of oxidation between two cysteine (amino acid) molecules forms this bond. Hence, Disulfide bond is characterized by a covalent linkage.

Answer:

The one cell of a unicellular organism must be able to perform all the functions necessary for life. These functions include metabolism, homeostasis and reproduction. Specifically, these single cells must transport materials, obtain and use energy, dispose of wastes, and continuously respond to their environment.

Answer:

A single celled Organism is able to get energy from complex molecules, to move, and to sense their environment.

Explanation:

The ability to perform these and other functions is part of their organization.

Answer: 1,2 and 5

Explanation:

Answer: B) 1,2, and 5

Explanation: got it right on edge

Answer:

This question contains a lot of subsections. Please find the variables to each question below

Explanation:

Hypothesis is a testable explanation to a scientific question. It aims at proffering a testable solution to an observed problem. It usually goes in an IF, THEN format.

Dependent variable is the variable being measured in an experiment, while the independent variable is the variable that is manipulated or changed by the experimenter.

The control group is the group that does not receive the experimental treatment while constant is the variable that is kept unchanged for all groups in the experiment.

Based on this explanation, find the answers to the hypothesis, independent variable, dependent variable, constant, and control groups to each question.

2. Dependent variable: How easy it is to remember

Independent variable: Color of the text

Control: Group given Black and White text to read

Constants: Same text

3. Hypothesis: If the temperature is increased, THEN the speed of ants increases or move faster

Independent variable: TEMPERATURE

Dependent variable: SPEED OF ANTS

Control: Ants placed in room temperature

Constants: SAME KIND OF ANTS

4. Hypothesis: IF the pH of the soil is acidic or alkaline, THEN the growth of strawberries will be inhibited

Independent variable: pH of soil

Dependent variable: Growth of strawberries

Control: Strawberries grown in a Neutral pH soil

Constants: Same type of plants (strawberries)

5. Hypothesis: IF caffeine is taken, then the blood pressure will be increased or raised.

Independent variable: CAFFEINE

Dependent variable: BLOOD PRESSURE

Control: Group given no caffeine

Constants: Same amount of caffeine

6. Hypothesis: IF music is played, THEN the heart rate increases

Independent variable: MUSIC

Dependent variable: HEART RATE

Control: Groups placed where no music is played

Constants: Same type of music, same time music runs for etc.

7. Hypothesis: IF bleach is present/used, THEN bacteria will die

Independent variable: Bleach

Dependent variable: Death of bacteria

Control: Bacteria given no bleach

Constants: Same species of bacteria, Same type of bleach

Answer:

A) Partial Pressure of dry air = 13.32 KPa

Partial Pressure of water vapour = 1.332 KPa

B) Humidity ratio; X = 0.0691

C) V_p = 0.8384 m³/Kg

Explanation:

A) We are given;

Temperature = 75°F

Relative Humidity = 45%

Now,to calculate the partial pressure, we will use the relationship;

Relative Humidity = (Partial Pressure/Vapour Pressure) × 100%

Making partial pressure the subject;

Partial Pressure = Relative Humidity × Vapour Pressure/100%

From the first table attached, at temperature of 75°F, the vapor pressure is 29.6 × 10^(-3) bar = 29.6 KPa

Thus;

Partial Pressure of dry air = (45 × 29.6)/100

Partial Pressure of dry air = 13.32 KPa

From online values, vapour pressure of water vapour at 75°F = 2.96 KPa

Thus;

Partial Pressure of water vapour = (45 × 2.96)/100 = 1.332 KPa

B) humidity ratio of moist air is given as;

X = 0.62198 pw / (pa - pw)  

where;

pw = partial pressure of the water vapor in moist air

pa = atmospheric pressure of the moist air

Thus;

X = (0.62198 × 1.332)/(13.32 - 1.332)  

X = 0.0691

C) Formula for moist air specific volume is;

V_p = (1 + (xRw/Ra) × RaT/p

Where;

V_p is specific volume

T is temperature = 75°F = 297.039 K

p is barometric pressure which in this case is standard sea level pressure = 101.325 KPa

pw is partial pressure of the water vapor in moist air = 1.332 KPa

Rw is individual gas constant for water = 0.4614 KJ/Kg.K

Ra is individual gas constant for air = 0.2869 KJ/Kg.K

V_p = (1 + (0.0691 * 0.4614/0.2869)) × 0.286.9 * 297.039/101.325

V_p = 0.8384 m³/Kg

Answer : The final hydrogen ion concentration is [tex]1.58\times 10^{-13}M[/tex]

Explanation :

The chemical reaction equation will be:

[tex]H_3PO_4+3NaOH\rightarrow Na_3PO_4+3H_2O[/tex]

In this reaction, 1 mole of [tex]H_3PO_4[/tex] reacts with 3 mole NaOH.

So, the number of moles of [tex]H_3PO_4[/tex] present in 150 ml of 0.1 M solution is calculated as follows.

Number of moles = Concentration × Volume

Number of moles = 0.1 M ×0.150 L = 0.015 mol

As it reacts with 3 moles of NaOH.

Number of moles of NaOH = 3 × 0.015 mol = 0.045 mol

So, moles of NaOH in 400 mL of 0.2 M NaOH is as follows.

Number of moles =  0.2 M × 0.4 L = 0.080 mol

Number of moles remained after the reaction = (0.080 - 0.045) mol  = 0.035 mol NaOH in 550 ml (400 ml + 150 ml)

As molarity is the number of moles present in liter of solution. Hence, molarity of NaOH is as follows.

[tex]\text{Molarity}=\frac{\text{Number of moles}}{\text{Volume of solution}}[/tex]

[tex]\text{Molarity}=\frac{0.035mol}{0.550L}=0.0636M[/tex]

Now we have to determine the hydroxide ion concentration.

As, [tex][OH^-][/tex] = 0.0636 M

[tex]pOH=-\log [OH^-][/tex]

[tex]pOH=-\log 0.0636[/tex]

[tex]pOH=1.20[/tex]

Now we have to determine the pH.

As,  pH + pOH = 14

pH = 14 - pOH

pH = 14 - 1.20

pH = 12.8

Now we have to determine the hydrogen ion concentration.

[tex]pH=-\log [H^+][/tex]

[tex]12.8=-\log [H^+][/tex]

[tex][H^+]=1.58\times 10^{-13}M[/tex]

Therefore, the final hydrogen ion concentration is [tex]1.58\times 10^{-13}M[/tex]