All categories

3 years ago

Question:

Chemistry

1 answer:

raketka [301]3 years ago

7 0

Answer:

luster means either sheen/glow or reflected light

Explanation:

luster is the appearance of mineral's surface in terms of light-reflective qualities

You might be interested in

A 45g Aluminum spoon (specific heat 0.88J/g degree Celcius) at 24 degrees Celcius placed in 180ml(180g) of coffee at 85 degrees

yarga [219]

Answer:

82 °C

Explanation:

Let the specific heat capacity of the coffee be that of water which is 4.2 J/g °C.

Now, at the final temperature, heat gained by Aluminum spoon ,Q equals heat lost by coffee, Q'.

Q = -Q'

Q = m₁c₁(T₂ - T₁) where m₁ = mass of aluminum spoon = 45 g, c₁ = specific heat of aluminum = 0.88 J/g °C, T₁ = initial temperature of aluminum spoon = 24 °C and T₂ = final temperature of aluminum spoon.

Q' = m₂c₂(T₂ - T₃) where m₂ = mass of coffee = 180 g, c₂ = specific heat of coffee = 4.2 J/g °C, T₃ = initial temperature of coffee = 85 °C and T₂ = final temperature of coffee.

So, Q = -Q'

m₁c₁(T₂ - T₁) = -m₂c₂(T₂ - T₃)

Making T₂ subject of the formula, we have

m₁c₁T₂ - m₁c₁T₁ = -m₂c₂T₂ + m₂c₂T₃

m₁c₁T₂ + m₂c₂T₂ = m₂c₂T₃ + m₁c₁T₁

(m₁c₁ + m₂c₂)T₂ = m₂c₂T₃ + m₁c₁T₁

T₂ = (m₂c₂T₃ + m₁c₁T₁)/(m₁c₁ + m₂c₂)

substituting the values of the variables into the equation, we have

T₂ = (180 g × 4.2 J/g °C × 85 °C + 45 g × 0.88 J/g °C × 24 °C )/(45 g × 0.88 J/g °C + 180 g × 4.2 J/g °C)

T₂ = (64260 J + 950.4 J)/(39.6 J/°C + 756 J/°C)

T₂ = 65210.4 J/795.6 J/°C

T₂ = 81.96 °C

T₂ ≅ 82 °C

8 0

3 years ago

The substance used by homeowners and municipal workers to melt ice on sidewalks and roadways is usually calcium chloride rather

Verizon [17]

Answer:

1. It dissolves much more ice faster than sodium chloride

2. Calcium chloride is more effective in melting ice at lower temperatures.

Explanation:

Salts are used to melt ice on roadways and sidewalks because they help to lower the freezing point of water.

Sodium chloride and calcium chloride are both salts used for this purpose but calcium chloride is usually preferred for the following two reasons:

1. It dissolves much more ice faster than sodium chloride: Calcium chloride dissolves much more ice faster than sodium chloride because when it dissociates, it produces three ions instead of the two produced when sodium chloride. Therefore, the heat of hydration of its ions is greater than that of sodium chloride.

2. Calcium chloride is more effective in melting ice at lower temperatures. It lowers the freezing point of water more than sodium chloride. Calcium chloride is able to lower the freezing point of water to about -52°C while sodium chloride only lowers it to about -6°C.

6 0

4 years ago

Indicate whether each of the following compounds will gave an acidic, basic or neutral solution when dissolved in water. Clear A

allsm [11]

Answer: ammonium bromide : acidic : The pH will be less than 7.

potassium cyanide : basic :The pH will be more than 7.

calcium nitrate: neutral : The pH will be approximately equal to 7.

calcium hypochlorite : basic :The pH will be more than 7.

Explanation:

pH is defined as the negative logarithm of hydrogen ion concentration. The scale ranges from 0 to 14.

When a solution is acidic, it will show a pH in the range of 0 - 6.9. When a solution is basic, it will show a pH in the range of 7.1 - 14. When a solution is neutral, it will show a pH of 7.

ammonium bromide : $NH_4Br$ : acidic as it is formed from the combination of strong acid HBr and weak base $NH_4OH$

potassium cyanide : $KCN$ : basic, as it is formed from the combination of weak acid HCN and strong base KOH

calcium nitrate: $Ca(NO_3)_2$ : neutral, as it is formed from the combination of strong acid and strong base.

calcium hypochlorite : $Ca(ClO)_2$ : basic, as it is formed from the combination of weak acid $HOCl$ and strong base $Ca(OH)_2$

3 0

4 years ago

What is the osmotic pressure in atm of

Dmitrij [34]

Answer:

12.2329 atm

Explanation:

Applying

PV = nRT.................... Equation 1

Make P the subject of the equation

P = (n/V)RT................ Equation 2

Where P = Osmotic pressure, (n/V) = Molarity of urea, T = Temperature, R = molar gas constant.

From the question,

Given: (n/V) = 0.5 M, T = 25°C = (273+25) = 298 K, R = 0.0821 Latm/mol.K

Substitute these values into equation 2

P = (0.5)(298)(0.0821)

P = 12.2329 atm

5 0

3 years ago

Write balanced complete ionic equation for hcl(aq)+lioh(aq)→h2o(l)+licl(aq)

olga2289 [7]

<span>H and Li have a +1 charge. Cl and OH have a -1 charge. When written out it should look like this: H(+1) + Cl(-1) + Li(+1) + OH(-1) --> H2O + Li(+1) + Cl(-1) if you wanted the net ionic equation it would be: H(+1) + OH(-1) --> H2O</span>

4 0

4 years ago

Read 2 more answers