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den301095 [7]
3 years ago
11

Calculate the density of an object with a mass of 20 g and a volume of 2.3 mL.

Chemistry
2 answers:
Mrrafil [7]3 years ago
4 0

Answer:

8.7g/mL

Explanation:

I used the density formula to solve. d=m/v= 20g/2.3mL

AfilCa [17]3 years ago
4 0

Answer:

8.7 g/ml

Explanation:

the formula for density is D = M/V

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Why is the brcl molecule polar? the shared electrons are closer to cl due to the greater electronegativity of chlorine. bromine
klio [65]
The shared electrons are closer to Cl due to the greater electronegativity of chlorine.
8 0
3 years ago
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When the coffee is brewed according to directions, a pound of coffee beans yields 50 cups of coffee (4 cups = 1 quart). How many
ycow [4]
About one kilogram of coffee beans is required 
3 0
3 years ago
How many moles of Mg(OH)2 will react with 2.5 mol HCI?
bekas [8.4K]

Answer:

1.25mole of Mg(OH)₂

Explanation:

The reaction is between Mg(OH)₂ and HCl, this is a neutralization reaction between an acid and a base.

         Mg(OH)₂   +   2HCl   →   MgCl₂   + 2H₂O

The balanced reaction equation is given above.

           2 mole of HCl reacts with 1 mole of Mg(OH)₂

So,       2.5mole of HCl will react with \frac{2.5}{2}  = 1.25mole of Mg(OH)₂

The number of moles of Mg(OH)₂ is given as 1.25mol

5 0
3 years ago
Any help would be appreciated. Confused.
masya89 [10]

Answer:

q(problem 1) = 25,050 joules;  q(problem 2) = 4.52 x 10⁶ joules

Explanation:

To understand these type problems one needs to go through a simple set of calculations relating to the 'HEATING CURVE OF WATER'. That is, consider the following problem ...

=> Calculate the total amount of heat needed to convert 10g ice at -10°C to steam at 110°C. Given are the following constants:

Heat of fusion (ΔHₓ) = 80 cal/gram

Heat of vaporization (ΔHv) = 540 cal/gram

specific heat of ice [c(i)] = 0.50 cal/gram·°C

specific heat of water [c(w)] = 1.00 cal/gram·°C

specific heat of steam [c(s)] = 0.48 cal/gram·°C

Now, the problem calculates the heat flow in each of five (5) phase transition regions based on the heating curve of water (see attached graph below this post) ...   Note two types of regions (1) regions of increasing slopes use q = mcΔT and (2) regions of zero slopes use q = m·ΔH.

q(warming ice) =  m·c(i)·ΔT = (10g)(0.50 cal/g°C)(10°C) = 50 cal

q(melting) = m·ΔHₓ = (10g)(80cal/g) 800 cal

q(warming water) = m·c(w)·ΔT = (10g)(1.00 cal/g°C)(100°C) = 1000 cal

q(evaporation of water) =  m·ΔHv = (10g)(540cal/g) = 5400 cal

q(heating steam) = m·c(s)·ΔT = (10g)(0.48 cal/g°C)(10°C) = 48 cal

Q(total) = ∑q = (50 + 800 + 1000 + 5400 + 48) = 7298 cals. => to convert to joules, multiply by 4.184 j/cal => q = 7298 cals x 4.184 j/cal = 30,534 joules = 30.5 Kj.

Now, for the problems in your post ... they represent fragments of the above problem. All you need to do is decide if the problem contains a temperature change (use q = m·c·ΔT) or does NOT contain a temperature change (use q = m·ΔH).    

Problem 1: Given Heat of Fusion of Water = 334 j/g, determine heat needed to melt 75g ice.

Since this is a phase transition (melting), NO temperature change occurs; use q = m·ΔHₓ = (75g)(334 j/g) = 25,050 joules.

Problem 2: Given Heat of Vaporization = 2260 j/g; determine the amount of heat needed to boil to vapor 2 Liters water ( = 2000 grams water ).

Since this is a phase transition (boiling = evaporation), NO temperature change occurs; use q = m·ΔHf = (2000g)(2260 j/g) = 4,520,000 joules = 4.52 x 10⁶ joules.

Problems containing a temperature change:

NOTE: A specific temperature change will be evident in the context of problems containing temperature change => use q = m·c·ΔT. Such is associated with the increasing slope regions of the heating curve.  Good luck on your efforts. Doc :-)

5 0
3 years ago
Why does it matter if atoms are divisible ???
Andreyy89

Atoms are divisible contrary to the early beliefs that the smallest "indivisible" matter is an atom. When an atom loses its identity it means that they are divisible. Atoms chemically react with other kinds of atoms thus changing their activity.

They certainly are not that important to our lives, but it’s good to know :)

5 0
2 years ago
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