Paint, paint thinners and some cleaning agents can weaken the shell of a hard hat and may eliminate

What are 3 characteristics of a mixture?

bogdanovich [222]

Answer:

The substances in a mixture can be separated using physical methods such as filtration, freezing, and distillation.

There is little, see Enthalpy of mixing, or no energy change when a mixture forms.

Mixtures have variable compositions, while compounds have a fixed, definite formula.

Explanation:

7 0

4 years ago

50 mL of 2.2 M HCl is combined with 50 mL of 2.0 M NaOH in a coffee-cup

GaryK [48]

Answer:

-56.1kJ/mol

Explanation:

The reaction between HCl and NaOH is:

NaOH + HCl → NaCl + H₂O + ΔH

Where ΔH is heat change in the reaction.

As the temperature of the solution increases, the heat is released and ΔH < 0

The heat released in the reaction is obtained using coffe-cup calorimeter equation:

Q = C×m×ΔT

Where Q is heat

C is specific heat of the solution (4.184J/g°C)

m is mass of solution: Assuming density = 1g/mL, 100mL of solution = 100g

And ΔT is change in temperature (13.4°C)

Replacing:

Q = C×m×ΔT

Q = -4.184J/g°C×100g×13.4

Q = -5606.6J

Now, in the reaction you have:

Moles HCl:

0.050L * (2.2mol/L) = 0.11 moles

Moles NaOH:

0.050L * (2.0mol/L) = 0.1 moles

That means the moles of reaction are 0.1 moles, and heat change in the chemical reaction is:

5606.6J / 0.1 mol = 56066J =

5 0

4 years ago

Maria owns a bakery and bakes many different types of yeast breads. One day she notices that the bread she baked is flat and doe

Novay_Z [31]

the yeast is probably not activated or old

7 0

3 years ago

90 POINTSSSS!!!

Katarina [22]

Answer:

$\large \boxed{\text{-2043.96 kJ/mol}}$

Explanation:

Assume the reaction is the combustion of propane.

Word equation: propane plus oxygen produces carbon dioxide and water

Chemical eqn: C₃H₈(g) + O₂(g) ⟶ CO₂(g) + H₂O(g)

Balanced eqn: C₃H₈(g) + 5O₂(g) ⟶ 3CO₂(g) + 4H₂O(g)

(a) Table of enthalpies of formation of reactants and products

$\begin{array}{cc}\textbf{Substance} & \textbf{$\Delta_{\text{f}}$H/(kJ/mol}) \\\text{C$_{3}$H$_{8}$(g)} & -103.85 \\\text{O}_{2}\text{(g)} & 0 \\\text{CO}_{2}\text{(g)} & -393.51 \\\text{H$_{2}$O(g)} & -241.82\\\end{array}$

(b)Total enthalpies of reactants and products

$\Delta_{\text{rxn}}H^{\circ} = \sum \left( \Delta_{\text{f}} H^{\circ} \text{products}\right) - \sum \left (\Delta_{\text{f}}H^{\circ} \text{reactants} \right)\\= \text{-2147.81 kJ/mol - (-103.85 kJ/mol)}\\= \text{-2147.81 kJ/mol + 103.85 kJ/mol}\\= \textbf{-2043.96 kJ/mol}\\\text{The enthalpy change is $\large \boxed{\textbf{-2043.96 kJ/mol}}$}$

ΔᵣH° is negative, so the reaction is exothermic.

5 0

3 years ago

A canister of 2.00 moles of helium has a volume of 30.0 L and is at a temperature of 293 Kelvin. what is the pressure of this ga

MAXImum [283]

Answer:

P = 162 KPa

Explanation:

Given data:

Number of moles = 2 mol

Volume of gas = 30.0 L

Temperature of gas = 293 K

Pressure of gas = ?

Solution:

The given problem will be solve by using general gas equation,

PV = nRT

P= Pressure

V = volume

n = number of moles

R = general gas constant = 0.0821 atm.L/ mol.K

T = temperature in kelvin

P = nRT/V

P = 2 mol ×0.0821 atm.L/ mol.K ×293 K/ 30.0 L

P = 48.11 atm.L/ 30.0 L

P = 1.6 atm

atm to kelvin:

1.6×101 = 162 KPa

5 0

3 years ago