Which of the following is true about technology and science

Bismuth oxide reacts with carbon to form bismuth metal: bi2o3(s) + 3c(s) → 2bi(s) + 3co(g) when 689 g of bi2o3 reacts with exces

ExtremeBDS [4]

Using the answer from the first part, we know that 2.957 moles of bismuth have formed. Moreover, the molar ratio between bismuth and carbon monoxide is:

2 : 3

Using the method of ratios,

2 : 3
2.957 : CO

CO = (3 * 2.957) / 2
CO = 4.4355

4.436 moles of carbon monoxide will be formed

8 0

3 years ago

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Use the standard reaction enthalpies given below to determine ΔH°rxn for the following reactionP4(g) + 10 Cl2(g) → 4PCl5(s) ΔH°r

weqwewe [10]

Answer:

Therefore $\bigtriangledown H^\circ_{rxn}$ = -1835 KJ

Explanation:

Enthalpy is denoted by H.

Enthalpy: Total heat change in a chemical reaction is called enthalpy.

The change of entalpy of a reaction is denoted by $\bigtriangledown H^\circ_{rxn}$

Hass's Law:The change in enthalpy of any process can be determined by calculating the sum of change in enthalpy of each of the steps involved in the process.

g= gas

S= solid

P₄(g)+10Cl₂(g)→ 4Cl₅(s) $\bigtriangledown H^\circ_{rxn}$ =?

PCl₅(s)→ PCl₃(g)+Cl₂(g) .......(1) $\bigtriangledown H^\circ_{rxn}$ = +157KJ

P₄(g)+6Cl₂(g)→ 4PCl₃(g).............(2) $\bigtriangledown H^\circ_{rxn}$ = -1207 KJ

If we flip a reaction the value of enthalpy will be change positive to negative or nagative to positive but the numerical value will be remain same.

We need rearrange the equation (1) because in the required equation Cl₂ is on the left side. So we flip the first equation.

PCl₃(g)+Cl₂(g)→PCl₅(s)......(3) $\bigtriangledown H^\circ_{rxn}$ = -157KJ

Multiplying 4 with equation (3)

4 PCl₃(g)+4Cl₂(g)→4PCl₅(s)......(4) $\bigtriangledown H^\circ_{rxn}$ =4×( -157)KJ= -628 KJ

Adding equation (2) and (4) we get

P₄(g)+6Cl₂(g)+4 PCl₃(g)+4Cl₂(g)→4PCl₃(g)+4PCl₅(s) $\bigtriangledown H^\circ_{rxn}$ =( -1207-628)KJ

⇒P₄(g)+10Cl₂(g)→4PCl₃(g)-4PCl₃(g)+4PCl₅(s) $\bigtriangledown H^\circ_{rxn}$ = - 1835KJ

⇒P₄(g)+10Cl₂(g)→ 4Cl₅(s) $\bigtriangledown H^\circ_{rxn}$ = -1835 KJ

Therefore $\bigtriangledown H^\circ_{rxn}$ = -1835 KJ

5 0

3 years ago

How many significant digits does the number 700 have?

OLga [1]

Answer: 700 has one significant figure which is 7.

Explanation: These are some rules for significant figures

•All non-zero digits are significant: 1,2,3,4,5,6,7,8,9

•Zero between non-zero digits are significant: They are three significant figures in 203.

•Leading zeros are not significant: There are two significant figures in 0.56.

•Trailing zero to the right of decimal are significant. There are four significant figures in 62.00

•Trailing zeros in a whole number with the decimal shown are significant: This makes "700." three significant figures.

•Trailing zeros in a whole number with no decimal shown are not significant: This makes 700 one significant figure.

5 0

3 years ago

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Question 5 of 5

grandymaker [24]

Answer:

B.

Explanation:

the SI unit for density is the kilogram per Cubic meter

7 0

3 years ago

How many molecules are in 5.50 grams of AgNO3?

mixas84 [53]

Answer:

1.95*10²² molecules are in 5.50 grams of AgNO₃

Explanation:

Being the molar mass of the elements:

Ag: 107.87 g/mole
N: 14 g/mole
O: 16 g/mole

then the molar mass of the compound is:

AgNO₃: 107.87 g/mole + 14 g/mole + 3*16 g/mole= 169.87 g/mole

Then you can apply the following rule of three: if 169.87 grams of the compound are present in 1 mole, 5.50 grams will be present in how many moles?

$moles=\frac{5.50 grams*1 mole}{169.87 grams}$

moles= 0.0324

Avogadro's Number or Avogadro's Constant is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023*10²³ particles per mole. Avogadro's number applies to any substance.

You can apply the following rule of three: if by definition of Avogadro's Number 1 mole of the substance contains 6.023 * 10²³ molecules, 0.0324 moles how many molecules will it have?

$molecules=\frac{0.0324 moles*6.023*10^{23} molecules}{1 mole}$

molecules=1.95*10²²

<u><em>1.95*10²² molecules are in 5.50 grams of AgNO₃</em></u>

3 0

3 years ago