When do you have to wear safety glasses while in lab?

Match the following. 1. an ancient study or art which attempted to combine science and philosophy to solve worldly problems atom

Zinaida [17]

Answer:

1. An ancient study or art which attempted to combine science and philosophy to solve worldly problems Alchemy

2. A homogeneous mixture of elements with metals to form metallic solids Alloy.

3. The simplest unit of an element that still retains the properties of that element compound Atom

4. Two or more elements joined together such that the elements have lost their individual identity Compound

5. A primary substance that cannot be divided into separate substances element Element.

6. The group of elements that are good conductors of electricity and heat Metals

7 . The group of elements that are poor conductors of electricity and heat Non metal

7 0

4 years ago

The thermal decomposition of N2O5 obeys first-order kinetics. At 45°C, a plot of ln[N2O5] versus t gives a slope of −6.40 × 10−4

finlep [7]

Answer:

1,080 min

Explanation:

A first order reaction follows the law:

$rate=k[A]$ , where [A] is the concentraion of the reactant A.

Equivalently:

$\dfrac{d[A]}{dt}=-k[A]$

Integrating:

$\dfrac{d[A]}{[A]}=-kdt$

$\ln \dfrac{[A]}{[A_o]}=-kt$

Half-life means [A]/[A₀] = 1/2, t = t½:

t½ = ln (2) / k

That means that the half-life is constant.

The slope of the plot of ln [N₂O₅] is -k. Then k is equal to 6.40 × 10⁻⁴ min⁻¹.

Thus, you can calculate t½:

t½ = ln(2) / 6.40 × 10⁻⁴ min⁻¹

t½ = 1,083 min.

Rounding to 3 significant figures, that is 1,080 min.

5 0

3 years ago

Be sure to answer all parts. In winemaking, the sugars in grapes undergo fermentation by yeast to yield CH3CH2OH (ethanol) and C

Ede4ka [16]

Answer:

a)- Fermentation = - 2 816 kJ/mol

Respiration = - 1409.2 kJ/mol

b)C₂H₅OH (l) + 3O₂ (g) → 3H₂O(g) + 2CO₂(g)

c) combustion per mol of sugar

Explanation:

a)

The fermentation of sugar is given as follows:

C₆H₁₂O₆ (s) + 6O₂ (g) → 6O₂ (g) + 6H₂O (l)

ΔHrxn = ΔHformation (products) - ΔHformation (reactants)

= (6 mol × -393.5kJ/mol)+ (6mol × -285.8kJ/mol) - (1 mol × -1260kJ/mol + 6mol × 0)

= -2 816 kJ/mol

The heat of combustion of ethanol is given as follows:

C₂H₅OH (l) + 3O₂ (g) → 3H₂O(g) + 2CO₂(g)

Let's assume that 1 mol of ethanol is burnt. The heat of reaction, ΔHrxn is given by this equation:

ΔHrxn = ΔHformation (products) - ΔHformation (reactants)

= (2 mol× - 393.5kJ/mol) + ( 3mol × -285.8kJ/mol) - [ (1mol × -235 kJ/mol) + ( 3mol × 0.0000kJ)]

= -1644 - (-235.2)

= - 1409.2 kJ/mol

Therefore, the combustion of ethanol is exothermic. In other words, heat iis given off (this is signified by the negative sign)

b) Ethanol, like any other fuel, burns up to give water and carbon dioxide. This is based on the assumption that the combustion is complete and no side reactions take place. The combustion of ethanol is given as follows:

C₂H₅OH (l) + 3O₂ (g) → 3H₂O(g) + 2CO₂(g)

The physical states are given in the parentheses.

c) From the comparisons of the ΔHrxn, sugar produces more energy.

4 0

4 years ago

10. Which description best matches Democritus's idea of the atom?

AlekseyPX

Answer:yes

Explanation:

8 0

2 years ago

Balance the equation AgCO3—> Ag+C+O2 and what type of reaction is it

Arturiano [62]

Answer:

Decomposition Reaction

2 AgCO₃ -----> 2 Ag + 2 C + 3 O₂

Explanation:

During the reaction, the reactant breaks down into smaller elements/compounds. As such, this is a decomposition reaction.

An equation is balanced when there is an equal amount of each element on both sides of the reaction. If these amounts are unequal, you can add coefficients to modify the quantities of particular elements/compounds. These coefficients must be as small as they can be while remaining whole numbers.

The unbalanced equation:

AgCO₃ -----> Ag + C + O₂

Reactants: 1 silver, 1 carbon, 3 oxygen

Products: 1 silver, 1 carbon, 2 oxygen

The balanced equation:

2 AgCO₃ -----> 2 Ag + 2 C + 3 O₂

Reactants: 2 silver, 2 carbon, 6 oxygen

Products: 2 silver, 2 carbon, 6 oxygen

6 0

2 years ago