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3 years ago

7

Which of the following is the best comparison of the density of basalt and granite? Basalt is more dense than granite Granite is

more dense than basalt Granite and basalt have equal densities The density of both is variable everywhere

2 answers:

LUCKY_DIMON [66]3 years ago

8 0

Basalt is more dense than granite because granite is made of lighter mass.

maria [59]3 years ago

4 0

Basalt is more dense than granite

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What caused the bonding of two atoms which undergo an ionic bond?

Keith_Richards [23]

C. As we know, an atom is made of three parts--protons (+), neutrons (core), and electrons (-) When one of these atoms loses one or more electron(s), it becomes a cation, or a positively charged ion. Inversely, when this atom gains a positively charged ion, [the atom] becomes a negatively charged atom, or an anion. The bond is made through electrostatic attraction, and a bond between these two "halves of a whole", it is known as an ionic bond.

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3 years ago

Which part of the flower produces seeds? (992 points)

Nata [24]

Answer:

The pistil, B.

Explanation:

The seeds are formed from the ovule which is contained in the ovary; all in the base, the pistil.

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2 years ago

A 101.2 ml sample of 1.00 m naoh is mixed with 50.6 ml of 1.00 m h2so4 in a large styrofoam coffee cup; the cup is fitted with a

Murrr4er [49]

The enthalpy change of the reaction when sodium hydroxide and sulfuric acid react can be calculated using the mass of solution, temperature change, and specific heat of water.

The balanced chemical equation for the reaction can be represented as,

$H_{2}SO_{4}(aq) + 2NaOH (aq) ----> Na_{2}SO_{4}(aq) + 2H_{2}O(l)$

Given volume of the solution = 101.2 mL + 50.6 mL = 151.8 mL

Heat of the reaction, q = $m C .$ Δ $T$

m is mass of the solution = 151.8 mL * $\frac{1 g}{1 mL} = 151.8 g$

C is the specific heat of solution = 4.18 $\frac{J}{g. ^{0}C}$

ΔT is the temperature change = $31.50^{0}C - 21.45^{0}C = 10.05^{0}C$

q = $151.8 g (4.18 \frac{J}{g ^{0}C})(10.05^{0}C) = 6377 J$

Moles of NaOH = $101.2 mL * \frac{1L}{1000 mL}*\frac{1.00 mol}{L} = 0.1012 mol$ NaOH

Moles of $H_{2}SO_{4}$ = $50.6 mL * \frac{1 L}{1000 mL} * \frac{1.0 mol}{1 L} = 0.0506 mol H_{2}SO_{4}$

Enthalpy of the reaction = $\frac{6377 J*\frac{1kJ}{1000J}}{0.0506 mol} = 126 kJ/mol$

5 0

3 years ago

Which of the following statements is true when considering temperature during a recrystallization? More than one answer may be c

Otrada [13]

Answer:

The correct answer is:

<em>(1) It is important that the sample is dissolved in just enough hot solvent. </em>

Explanation:

The process of recrystallization is important to eliminate the impurities and to obtain better crystals of the solid. The solvent used to perform the recrystallization must have a high dissolution power of the substance to be recrystallized and a low dissolution power of the impurities. This is in order to eliminate most impurities. Furthermore, <em>It is important that the sample is dissolved in just enough hot solvent </em>because this should be easy to remove after the recrystallization and the crystal should form easily when the solution cools. Also, it is better to add the hot solvent to solubilize the crystals and keep the impurities insoluble, instead of adding the cold solvent and heating the solution. Additionally, the process of cooling the solution must be done slowly to obtain large and fewer crystals. A fast ice-cooling will form smaller crystals.

4 0

3 years ago

The compound dioxane, which is used as a solvent in various industrial processes is composed of C,H, and O atoms. Combustion of

Lady_Fox [76]

Answer:

The correct formula of dioxane is C₄H₈O₂.

Explanation:

Given data:

mass of dioxane= 2.23 g

mass of water = 1.802 g

mass of carbon dioxide = 4.401 g

molar mass of dioxane = 88.1 g / mol

Molecular formula of dioxane = ?

Solution:

percentage of carbon = (4.401 g/2.23 g ) × (12 /44) × 100

= (1.98 × 0.273) × 100 = 54.1

percentage of hydrogen = (1.802 g/ 2.23 g) × (2.016 /18.016) × 100

= (0.81 × 0.112) × 100 = 9.072

percentage of oxygen = 100 - (54.1 + 9.072)

= 100 - 63.172 = 36.828

Now we will determine the number of grams atoms of carbon, hydrogen and oxygen.

No. of gram atoms of carbon = 54.1 /12 = 4.51

No. of gram atoms of hydrogen = 9.072 / 1.008 = 9

No. of gram atoms of oxygen = 36.828 / 16 = 2.302

Atomic ratio:

C :H :O 4.51/ 2.302 : 9 / 2.302 : 2.302 /2.302

C :H :O 2 : 4 : 1

Molecular formula:

Molecular formula = n × (empirical formula)

n = molar mass of compound / empirical formula mass

empirical formula mass= 2 × 12 + 4 × 1.008 + 1 × 16

empirical formula mass= 24+ 4.032 +16 = 44.032

n = 88.1 / 44.032 = 2

Molecular formula = n × (empirical formula)

Molecular formula = 2 × (C₂H₄O)

Molecular formula = C₄H₈O₂

8 0

3 years ago