Which substance has AHf defined as O kJ/mol?

Which of the following is a valid unit for specific heat?

Marysya12 [62]

Answer:

The answer is D

Explanation:

6 0

3 years ago

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Using the graphic provided,idenify the reactants of photosynthesis?

Y_Kistochka [10]

Answer:

water, carbon dioxide reacted in the presence of sun light and chlorophyll and form glucose and oxygen.

Explanation:

Photosynthesis:

It is the process in which in the presence of sun light and chlorophyll by using carbon dioxide and water plants produce the oxygen and glucose.

Carbon dioxide + water + energy → glucose + oxygen

water is supplied through the roots, carbon dioxide collected through stomata and sun light is capture by chloroplast.

Chemical equation:

6H₂O + 6CO₂ + energy → C₆H₁₂O₆ + 6O₂

it is known from balanced chemical equation that 6 moles of carbon dioxide react with the six moles of water so, the mass of water will be,

The glucose is converted into pyruvate and prod

7 0

4 years ago

The following is an example of which type of chemical reaction?Na (s) + H2O (l) Imported Asset NaOH (aq) + H2 (g)

lora16 [44]

Answer:

The answer to your question is Single replacement

Explanation:

Data

Chemical reaction

Na + H₂O ⇒ NaOH + H₂

Single replacement is a chemical reaction in which a metal replaces the cation of a compound.

Decomposition is a chemical reaction in which a compound forms 2 or more products.

Double replacement in this chemical reaction two compounds react interchanging their cations and anions.

Combustion in this chemical reaction the reactants must be a compound with carbon and the other oxygen and the products must be carbon dioxide and water.

4 0

3 years ago

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s e vapor pressure of the waterretnylene glycol solution at 32 "C? 5. What is the Boiling Point of the solution resulted from th

lyudmila [28]

Answer:

What is the Boiling Point of the solution resulted from the dissolving of 32.5 g of NaCl in 250.0 g of water? 102,31°C

Explanation:

This question involves the Elevation of boiling point

ΔT = Kb . m . i

(T°solution - T°solvent pure) = Ebulloscopic constant . molality . Van 't Hoff factor

Van 't Hoff factor is 2 for NaCl because you have two ions on disociation.

Kb for water is, 0,52 °C . kg/mol - It is a known value.

You know that water pure boils at 100°C so let's build the formula

(T°solution - 100°C) = 0,52 °C.kg/mol . molality . 2

We have to find out the molality (moles of solute/1kg solvent)

In 250 g H2O we have 32,5 g NaCl so the rule of three will be

250 g H2O ______32,5 g NaCl

1000g __________ (1000g . 32,5g) / 250g = 130 g NaCl

Molar mass NaCl : 58,45 g/m

Moles NaCl : mass/ molar mass --> 130g /58,45 g/m = 2,22 m

(T°solution - 100°C) = 0,52 °C.kg/mol . 2,22 mol/gk . 2

T°solution - 100°C = 2,31 °C

T° at boiling point in the solution = 2,31°C + 100°C = 102,31°C

3 0

3 years ago

A chemist titrates 110.0 mL of a 0.7684 M methylamine (CH3NH2) sotion with 0.4469 M HNO3 solution at 25 °C. Calculate the pH at

Firdavs [7]

Answer: The pH at equivalence point for the given solution is 5.59.

Explanation:

At the equivalence point,

$n_{HNO_{3}} = n_{CH_{3}NH_{2}}$

So, first we will calculate the moles of $CH_{3}NH_{2}$ as follows.

$n_{CH_{3}NH_{2}} = 0.764 M \times \frac{110 ml}{1000 ml/L}$

= 0.0845 mol

Now, volume of $HNO_{3}$ present will be calculated as follows.

Volume = $\frac{\text{no. of moles}}{\text{Molarity}}$

= $\frac{0.0845}{0.4469 M}$

= 0.1891 L

Therefore, the total volume will be the sum of the given volumes as follows.

110 ml + 189.1 ml

= 299.13 ml

or, = 0.2991 L

Now, $[CH_{3}NH_{3}^{+}] = \frac{0.0845 mol}{0.2991 L}$

= 0.283 M

Chemical equation for this reaction is as follows.

$CH_{3}NH_{3}^{+} + H_{2}O \rightleftharpoons CH_{3}NH_{2} + H_{3}O^{+}$

As, $k_{a} = \frac{k_{w}}{k_{b}}$

= $\frac{10^{-14}}{10^{-3.36}}$

= $2.29 \times 10^{-11}$

Now, $[HNO_{3}] = \sqrt{k_{a}[CH_{3}NH_{3}^{+}]}$

= $\sqrt{2.29 \times 10^{-11} \times 0.283}$

= $2.546 \times 10^{-6}$

Now, pH will be calculated as follows.

pH = $-log [H_{3}O^{+}]$

= $-log (2.546 \times 10^{-6})$

= 5.59

Thus, we can conclude that pH at equivalence point for the given solution is 5.59.

6 0

3 years ago