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Brilliant_brown [7]

3 years ago

11

which of the following pieces of chemical lab equipment would we use to heat up a crucible or evaporating dish to a very high te

mperature

1 answer:

snow_lady [41]3 years ago

6 0

Answer:Bunser buner

Explanation: It is meant to heat solid and liquid substance in the lab.

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Which of he following statements describes a limitation of the food web model?

Hunter-Best [27]

Answer:

nothing

Explanation:

4 0

3 years ago

while looking at calcuim (Ca) on the periodic table a student needs to find with a greater atomic mass in the same period.Where

UkoKoshka [18]

To the right of calcium and in the same period.

8 0

3 years ago

Read 2 more answers

Someone help please :)

zlopas [31]

6.79 x 10⁶

<h3>Further explanation </h3>

Scientific Notation consists of 2 parts

1. the first part: the first digit followed by the decimal point

2. The second part: the power of 10 (the exponents).which shows the number of digits after the decimal point

To add/subtract, the exponents must be the same and then add/subtract the coefficient

convert the largest exponent

$\tt 7.2\times 10^6\rightarrow 72\times 10^5$

subtract the coefficients

$\tt =(72-4.1)\times 10^5\\\\=67.9\times 10^5\rightarrow 6.79\times 10^6$

7 0

3 years ago

Hydrogen reacts with chlorine to form hydrogen chloride (HCl (g), mc012-1.jpgHf = –92.3 kJ/mol) according to the reaction below.

Kobotan [32]

<u>Given:</u>

H2(g) + Cl2 (g) → 2HCl (g)

<u>To determine:</u>

The enthalpy of the reaction and whether it is endo or exothermic

<u>Explanation:</u>

Enthalpy of a reaction is given by the difference between the enthalpy of formation of reactants and products

ΔH = ∑nHf (products) - ∑nHf (reactants)

= [2Hf(HCl)] - [Hf(H2) + Hf(Cl2)] = 2 (-92.3) kJ = - 184.6 kJ

Since the reaction enthalpy is negative, the reaction is exothermic

<u>Ans:</u> The enthalpy of reaction is -184. kJ and the reaction is exothermic

3 0

3 years ago

Read 2 more answers

The complete combustion of propane (C3H8) in the presence of oxygen yields CO2 and H2O: C3H8 (g) + 5O2 (g) 3CO2 (g) + 4H2O (g) a

mixas84 [53]

Answer:

26.9 L is the volume of CO₂, we obtained

Explanation:

The reaction is: C₃H₈(g) + 5O₂(g) → 3CO₂ (g) + 4H₂O (g)

Let's determine the reactants moles:

27.5 g . 1mol / 44 g = 0.625 moles

We need density of O₂ to determine mass and then, the moles.

O₂ density = O₂ mass / O₂ volume

O₂ density . O₂ volume = O₂ mass

1.429 g/L . 45L = O₂ mass → 64.3 g

Moles of O₂ → 64.3 g . 1mol/32g = 2.009 moles

Let's find out the limiting reactant:

1 mol of propane needs 5 moles of oxygen to react

Then, 0.625 moles will react with (0.625 . 5)/1 = 3.125 moles of O₂

Oxygen is the limiting reactant, we need 3.125 moles but we only have 2.009 moles

Ratio is 5:3. 5 moles of O₂ produce 3 moles of CO₂

Therefore, 2.009 moles of O₂ must produce (2.009 .3) /5 = 1.21 moles of CO₂. Let's find out the volume, by Ideal Gases Law (STP are 1 atm and 273K, the standard conditions)

1 atm . V = 1.21 moles . 0.082 . 273K

V = (1.21 moles . 0.082 . 273K) / 1atm = 26.9 L

3 0

3 years ago