2. How do chemical weathering and deposition contribute to the formation of the features shown here?

How many molecules of water are represented by the formula h2o

yaroslaw [1]

exactly 1 molecule of water is H2O just 1 is the answer

4 0

3 years ago

Calculate the number of moles of solute present in 55.0 mg of an aqueous solution that is 1.45 m NaCl. Assume that for dilute aq

Aloiza [94]

Answer:

0.00007975 mole

Explanation:

Number of moles can be calculated as; mass of solute/volume of solvent or concentration of solution x volume of that solution.

In this case:

Concentration of solution = 1.45 M

Mass of solvent (water in this case) = 55.0 mg

55.0 mg of water is equivalent to 0.55 ml of water.

Therefore, volume of solution = 0.055 ml

Hence, number of moles of solute = molarity x volume

1.45 x 0.000055 = 0.00007975 mole

8 0

3 years ago

A 62.6-gram piece of heated limestone is placed into 75.0 grams of water at 23.1°C. The limestone and the water come to a final

KATRIN_1 [288]

Answer : The initial temperature of the limestone is $1.05\times 10^{2}^oC$ .

Solution : Given,

Mass of limestone = 62.6 g

Mass of water = 75 g

Final temperature of limestone = $51.9^oC$

Final temperature of water = $51.9^oC$

Initial temperature of water = $23.1^oC$

The specific heat capacity of limestone = $0.921J/g^oC$

The specific heat capacity of water = $4.186J/g^oC$

The formula used :

q = m × c × ΔT

where,

q = heat required

m = mass of an element

c = heat capacity

ΔT = change in temperature

According to this, the energy as heat lost by the system is equal to the gained by the surroundings.

Now the above formula converted and we get

$q_{system}=-q_{surrounding}$

$m_{system}\times c_{system}\times (T_{final}-T_{initial})_{system}= -[m_{surrounding}\times c_{surrounding}\times (T_{final}-T_{initial})_{surrounding}]$

$m_{limestone}\times c_{limestone}\times (T_{final}-T_{initial})_{limestone}= -[m_{water}\times c_{water}\times (T_{final}-T_{initial})_{water}]$

Now put all the given values in this formula, we get

$62.6g\times 0.921J/g^{0}C \times (51.9^{0}C-T_{\text{ initial limestone}})= -[75g\times 4.186J/g^{0}C \times (51.9^{0}C-23.1^oC)]$

By rearranging the terms, we get the value of initial temperature of limestone.

$T_{\text{ initial limestone}}=104.926^{0}C=1.05\times 10^{2}^oC$

Therefore, the initial temperature of the limestone is $1.05\times 10^{2}^oC$ .

8 0

3 years ago

Read 2 more answers

Which best describes a scientist who solves a new problem using something already learned?

adelina 88 [10]

Answer:

The answer should be Skeptical

6 0

3 years ago

Which statements are true? Δ???? for an exothermic reaction is positive. Δ???? for an endothermic reaction is positive. The evap

LuckyWell [14K]

Answer: The true statements are $\Delta H$ for an endothermic reaction is positive, a combustion reaction is exothermic and when energy is transferred as heat from the system to the surroundings, $\Delta H$ is negative.

Explanation:

There are 2 types of chemical reactions categorized into heat change:

Endothermic reactions: These reactions are defined as the reactions in which energy is absorbed by the system from the surroundings. The $\Delta H$ for these reactions is always positive. For Example: Changing of water into water vapor.
Exothermic reactions: These reactions are defined as the reactions in which energy is released by the system to the surroundings. The $\Delta H$ for these reactions is always negative. For Example: Combustion reactions.

Combustion reactions are defined as the reactions in which a hydrocarbon reacts with oxygen gas to produce carbon dioxide and water. Heat is released during these reactions. Thus, it is considered as exothermic reactions.

Hence, the true statements are $\Delta H$ for an endothermic reaction is positive, a combustion reaction is exothermic and when energy is transferred as heat from the system to the surroundings, $\Delta H$ is negative.

6 0

4 years ago