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Answer:

Explanation:

The preceding chapter introduced the use of element symbols to represent individual atoms. When atoms gain or lose electrons to yield ions, or combine with other atoms to form molecules, their symbols are modified or combined to generate chemical formulas that appropriately represent these species. Extending this symbolism to represent both the identities and the relative quantities of substances undergoing a chemical (or physical) change involves writing and balancing a chemical equation. Consider as an example the reaction between one methane molecule (CH4) and two diatomic oxygen molecules (O2) to produce one carbon dioxide molecule (CO2) and two water molecules (H2O). The chemical equation representing this process is provided in the upper half of Figure 1, with space-filling molecular models shown in the lower half of the figure.

Final answer:

In a balanced chemical equation, a subscript is a number to the right of an element indicating the number of atoms in a molecule. A coefficient is a number to the left of a formula indicating the number of molecules. Only coefficients should be altered when balancing equations.

Explanation:

In the context of a balanced chemical equation, a subscript is a number to the lower right of an element or ion within a formula and it applies to the number of atoms of that element in a molecule. A coefficient is a number placed to the left of a formula and it applies to the number of molecules of the entire substance. Only coefficients should be changed when balancing chemical equations because altering subscripts changes the substance itself.

The balanced chemical equation is a symbolic representation of a chemical reaction, where the number of each type of atom is equalized for both the products and reactants, in accordance with the law of conservation of matter.

For example, in the equation 2H₂O, the subscript '2' to the right of 'H' shows that there are two hydrogen atoms in one water molecule, and the coefficient '2' to the left of 'H₂O' means there are two molecules of water, totaling four hydrogen atoms.

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Answer:

You can eat one chunk white tuna of 6 oz every 21,5 minutes

And, you can eat one chunk linght tuna of 6 oz every 5 minutes

Explanation:

The exposure to mercury may cause serious health problems, and is a threat to the development of the child in utero and early in life.

If you weight 68 kg you can eat:

68 kg * 0,1mgHg/ kg = 6,8 mg Hg per day

• Chunk white tuna contains 0,6 mg Hg/kg

Thus, you can eat:

6,8 mg Hg * 1 kg tuna/ 0,6 mg Hg = 11,33 kg of chunk white tuna per day

In ounces:

11,33 kg * 35,274oz/ 1 kg = 400 oz per day

You can eat 66,7 6 ounces of chunk white tuna per day. One every 21,5 minutes

• Chunk light tuna contains 0,14 mg Hg/kg

Thus, you can eat:

6,8 mg Hg * 1 kg tuna/ 0,14 mg Hg = 48,57 kg of chunk white tuna per day

In ounces:

48,57 kg * 35,274oz/ 1 kg = 1713 oz per day

You can eat 285,6 6 ounces of chunk white tuna per day. One every 5 minutes

I hope it helps!

Answer:

The correct answer is option B.

Explanation:

Significant figures :These are figures in a number which expresses the value of the magnitude of a quantity to a specific degree of accuracy is known as significant digits.

Significant digits in the volume measurement 0.010 mL are:

= 2 significant figures

• All non-zero numbers are always significant.
• All zero’s preceding the first integers are never significant.
• All zero’s after the decimal point are always significant.

The volume measurement "0.010 mL" contains two significant digits. Significant digits are nonzero digits and trailing zeros in decimal numbers that contribute to the precision of the measurement.

In the volume measurement "0.010 mL," there are two significant digits. Significant digits are the digits in a measured quantity that contribute to its precision or accuracy. To identify significant digits, consider the following rules:

1. All nonzero digits are significant. In this case, "0" is considered a nonzero digit because it appears between two nonzero digits.

2. Leading zeros (zeros to the left of the first nonzero digit) are not significant. In "0.010 mL," the leading zero is not considered a significant digit.

3. Trailing zeros (zeros to the right of the last nonzero digit) in a decimal number are significant. So, the two trailing zeros in "0.010 mL" are significant.

Therefore, the measurement "0.010 mL" has two significant digits (the "1" and the "0"), and the correct answer is B) 2. These two significant digits represent the precision of the volume measurement.

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Answer:

i) pH = 0.6990

ii) pH = 2.389

Explanation:

i) Before adding aqueous NaOH, there are 25.00 mL of 0.2000 M HCl. HCl reacts with the water in the aqueous solution as follows:

HCl + H₂O ⇒ H₃O⁺ + Cl⁻

The HCl and H₃O⁺ are related to each other through a 1:1 molar ratio, so the concentration of H₃O⁺ is equal to the HCl concentration.

The pH is related to the hydronium ion concentration as follows:

pH = -log([H₃O⁺]) = -log(0.2000) = 0.699

ii) Addition of NaOH causes the following reaction:

H₃O⁺ + NaOH ⇒ 2H₂O + Na⁺

The H₃O⁺ and NaOH react in a 1:1 molar ratio. The amount of NaOH added is calculated:

n = CV = (0.2000 mol/L)(24.00 mL) = 4.800 mmol NaOH

Thus, 4.800 mmol of H₃O⁺ were neutralized.

The initial amount of H₃O⁺ present was:

n = CV = (0.2000 mol/L)(25.00 mL) = 5.000 mmol H₃O⁺

The amount of H₃O⁺ that remains after addition of NaOH is:

(5.000 mmol) - (4.800 mmol) = 0.2000 mmol

The concentration of H₃O⁺ is the amount of H₃O⁺ divided by the total volume. The total volume is (25.00 mL) + (24.00 mL ) = 49.00 mL

C = n/V = (0.2000 mmol) / (49.00 mL) = 0.004082 M

The pH is finally calculated:

pH = -log([H₃O⁺]) = -log(0.004082) = 2.389

Answer:

1. B

2. A

3. C

4. C

5. D

Explanation:

Soil is regarded as the solid unconsolidated material of the earth crust. Soil is of three different types namely: Sandy soil, clay soil and loamy soil. These three different soil types possess different properties that distinguish them. Some of them are:

- CLAY soil is characterized as having the finest particles and can hold greater amount of water i.e. have a high water holding capacity.

- LOAMY SOIL is the best soil type for planting agricultural crops because it has the highest concentration of nutrients that suited for plant growth.

- loamy, Sandy and clay differ in how we feel when touched i.e. texture, and colour.

- SANDY soils are the kind of soils that are found in Sea shores and beaches.

- Soil is important to living things as it forms part of the earth where animals live, provides the necessary nutrients needed by plants, serves as a place where people live.

Answer:

The three subatomic particles are the particles contained in the iota. They are protons, neutrons, and electrons. Protons and electrons convey a positive and negative charge, individually, while neutrons don't convey any change

Explanation: