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3 years ago

How are the elements in the periodic table arranged from left to right and top to bottom based on what value?

1 answer:

5 0

Well, elements are arranged based on a number of factors.

Left to right, elements are arranged based on atomic number. The atomic numbers of the elements are increasing by 1 as you move from left to right.

Top to bottom is based on increasing atomic radius. As you move from top to bottom, each succeeding element in a group gets an additional electron shell, increasing the atomic radius as you move down.

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Which organelle acts as a temporary storage center, containing water,

JulsSmile [24]

The correct answer would be C, vacuole.

5 0

3 years ago

Read 2 more answers

When 2.499 g of AX (s) dissolves in 135.3 g of water in a coffee-cup calorimeter the temperature rises from 23.6 °C to 35.2 °C.

Elena L [17]

Answer:

The enthalpy change for the solution process $\Delta H_{rxn}$ = - 158.34 kJ/mol

Explanation:

Given that:

The mass of salt AX = 2.499 g

The mass of water = 135.3 g

The mass of the solution = ( 2.499 + 135.3 ) g = 137.799 g

The specific heat of salt solution s is known to be = 4.18 J/g° C

The change in temperature i.e. ΔT = 35.2 °C - 23.6 °C = 11.6 °C

Thus, the amount of heat raised is equal to the heat absorbed by the calorimeter.

∴

$q_{reaction} = q_{solution}$

$q_{reaction} = -ms_{solution} \Delta T$

$q_{reaction} = -137.799 \ g \times 4.18 \dfrac{J}{g^0C}\times 11.6^0C$

$q_{reaction} = - 6682 \ J$

$q_{reaction} = - 6.682 \ kJ$

Recall that the mass of the salt = 2.499 g

The number of moles of the salt = $2.499 \ g \times \dfrac{1 \ mol \ of \ AX}{59.1097 \ g}$

= 0.0422 mol of AX

Finally the enthalpy change, $\Delta H_{rxn} = \dfrac{- 6.682 \ kJ}{ 0.0422 \ mol}$

= - 158.34 kJ/mol

The enthalpy change for the solution process $\Delta H_{rxn}$ = - 158.34 kJ/mol

3 0

3 years ago

A scientist formulates the following hypothesis: If plants of the same species

Blababa [14]

Answer:

Growth rate

Explanation:

The responding variable, also known as the DEPENDENT VARIABLE, is the variable that responds to changes or manipulations made to another variable (independent or manipulable variable) in the experiment. It is the measured variable of an experiment.

According to the hypothesis provided for this investigation, the scientist wants to determine if the amount of fertilizer plants of the same species receive will affect their growth rate when planted in the same condition. This shows that the independent variable is the amount of fertilizer to be used while the RESPONDING VARIABLE OR DEPENDENT VARIABLE is the GROWTH RATE OF THE PLANTS because it responds to the amount of fertilizer.

7 0

3 years ago

How many grams of oxygen are required to react with 2.7 g of dihydrogen sulfide

KatRina [158]

Answer:

Mass = 3.84 g

Explanation:

Given data:

Mass of hydrogen sulfide = 2.7 g

Mass of oxygen required = ?

Solution:

Chemical equation:

2H₂S + 3O₂ → 2H₂O + 2SO₂

Number of moles of hydrogen sulfide:

Number of moles = mass/ molar mass

Number of moles = 2.7 g / 34 g/mol

Number of moles = 0.08 mol

Now we will compare the moles of hydrogen sulfide with oxygen.

H₂S : O₂

2 : 3

0.08 : 3/2 ×0.08 = 0.12 mol

Mass of oxygen;

Mass = number of moles × molar mass

Mass = 0.12 mol × 32 g/mol

Mass = 3.84 g

3 0

4 years ago

In an aqueous chloride solution cobalt(II) exists in equilibrium with the complex ion CoCl42-. Co2 (aq) is pink and CoCl42-(aq)

kolezko [41]

Answer:

1. This reaction is (A) Exothermic .

2. When the temperature is decreased the equilibrium constant, K: (A) Increases

3.When the temperature is decreased the equilibrium concentration of Co2: (A) Increases

Explanation:

$CoCl4^2-(aq) Co_2+(aq) + 4Cl^-(aq)$

1. The pink color predominates at low temperatures, indicating that the commodity is preferred.

This is a reaction that is exothermic.

2. As the decrease in the temperature , the equilibrium constant , K ;

equilibrium constant = $\frac{product}{reactant}$ = $\frac{[CO^2^+][Cl^-^4]}{CoCl^2^-_4}$

As the temperature drops, the concentration of $Cl^-$ and $CO^2^+$ rises, and K rises as well , thus it increases .

3. The equilibrium concentration of $CO^2^+$ decreases as the temperature decreases:

When the temperature is lowered, the equilibrium shifts to the right , that is it increases.

4 0

3 years ago