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3 years ago

5) answer is A

Chemistry

1 answer:

Burka [1]3 years ago

3 0

Answer:

A) positive; added

Explanation:

Based on the reaction:

2NaHCO3(s) + 129kJ → Na2CO3(s) + H2(g) + CO2(g)

<em>2 moles of NaHCO3 requires 129kJ to produce 1 mole of Na2CO3, 1 mole of H2 and 1 mole of CO2.</em>

<em />

That means, the energy must be added being, thus, an exothermic reaction. The exothermic reactions have ΔH >0.

Thus, right answer is:

A) positive; added

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Compound X has a molar mass of 316.25 g*mol^-1 and the following composition:

Leokris [45]

Answer:

Compound X has a molar mass of 316.25 g*mol^-1 and the following composition:

element & mass %

phosphorus & 39.18%

sulfur & 60.82%

Write the molecular formula of X.

Explanation:

The given molecule of phosphorus and sulfur has molar mass --- 316.25 g.

Empirical formula calculation:

element: phosphorus sulfur

co9mposition: 39.185% 60.82%

divide with

atomic mass: 39.185/31.0 g/mol 60.82/32.0g/mol

=1.26mol 1.90mol

smallest mole ratio: 1.26mol/1.26mol =1 1.90mol/1.26 mol =1.50

multiply with 2: 2 3

Hence, the empirical formula is:

P2S3.

Mass of empirical formula is:

158.0g/mol

Given, molecule has molar mass --- 316.25 g/mol

Hence, the ratio is:

316.25g/mol/158.0 =2

Hence, the molecular formula of the compound is :

2 x (P2S3)

= $P_4S_6$

8 0

3 years ago

Help meeeeeeeeeeeeeee

lesya [120]

AMSWER :

CHEMICAL FORMULA :

• WATER - H2O

• CARBONDIOXIDE - CO2

• SODIUM HYDROXIDE - NaOH

• SULPHURIC ACID - H2SO4

• SODIUM CHLORIDE - NaCI

• SODIUM BICARBONATE - NaCHO3

8 0

2 years ago

The N2O4−NO2 reversible reaction is found to have the following equilibrium partial pressures at 100∘C. Calculate Kp for the rea

timofeeve [1]

Answer:

$K_{p}$ for the reaction is 18.05

Explanation:

Equilibrium constant in terms of partial pressure ( $K_{p}$ ) for this reaction can be written as-

$K_{p}=\frac{P_{NO_{2}}^{2}}{P_{N_{2}O_{4}}}$

where $P_{NO_{2}}$ and $P_{N_{2}O_{4}}$ are equilibrium partial pressure of $NO_{2}$ and $N_{2}O_{4}$ respectively

Hence $K_{p}=\frac{(0.095)^{2}}{(0.0005)}$ = 18.05

So, $K_{p}$ for the reaction is 18.05

3 0

4 years ago

A person's heartbeat is 73 beats per minute. If his heart beats 3.1e9 times in a lifetime, how long does the person live?

tiny-mole [99]

Answer: The person lived for 80.66 years.

Explanation:

Heart beat of the person = 73 beat /min

Number of total heart beats = $3.1\times 10^{9}$

Life span of the person : $\frac{\text{Total heart beats of the person}}{\text{Heart beat per minute}}=\frac{3.1\times 10^{9} beats}{73 beat/min}$

1 year =525600 mins

Life span = $0.0424\times 10^{9} min=80.66 years$

The person lived for 80.66 years.

7 0

3 years ago

How do you convert from grabs to moles of a substance

Lorico [155]

The correct question is as follows:

How do you convert from grams to moles of a substance

1. Divide by the molar mass

2. Subtract the molar mass

3. Add the molar mass

4. Multiple by the molar mass

Answer: In order to convert from grams to moles of a substance divide by the molar mass.

Explanation:

The number of moles of a substance is the mass of substance in grams divided by its molar mass.

The formula to calculate moles is as follows.

$Moles = \frac{mass}{molar mass}$

This means that grams are converted to moles when grams is divided by molar mass.

Thus, we can conclude that in order to convert from grams to moles of a substance divide by the molar mass.

8 0

3 years ago