1. The calculated density of the sample is 12.6 g/cm³
2. The sample is silver (option B)
<h3>Definition of density </h3>
The density of an object is defined as the mass of the object per unit volume of the object. Mathematically is expressed as:
Density = mass / volume
<h3>1. How to determine the density </h3>
- Mass = 15.12 g
- Volume = 1.20 cm³
- Density =?
Density = mass / volume
Density = 15.12 / 1.20
Density = 12.6 g/cm³
<h3>2. How to determine the sample </h3>
- Density of copper = 8.95 g/cm³
- Density of silver = 12.59 g/cm³
- Density of gold = 19.32 g/cm³
- Calculate density = 12.6 g/cm³
- Sample =?
From the above we can see that the calculated density is the approximate density of silver.
Therefore, the sample is silver
Learn more about density:
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<u>Answer:</u> The excess reagent for a given reaction is nitrogen dioxide.
<u>Explanation:</u>
Limiting reagent is defined as the reagent which is present in less amount and also it limits the formation of products.
Excess reagent is defined as the reagent which is present in large amount.
For the given chemical reaction:
By stoichiometry of the reaction:
1 mole of water reacts with 3 moles of nitrogen dioxide gas
So, 0.5 moles of water will react with = 
of nitrogen dioxide gas.
As, the given amount of nitrogen dioxide gas is more than the required amount. Thus, it is considered as an excess reagent.
Hence, nitrogen dioxide is an excess reagent.
Using the ideal gas law PV =nRTPV=nRT , we find that the pressure will be P =\frac{nRT}{V}P=
V
nRT
. Then, we'll substitute and find the pressure, using T = -25 °C = 248.15 K and R = 0.0821 \frac{atm\cdot L}{mol \cdot K}
mol⋅K
atm⋅L
:
P =\frac{nRT}{V} = \frac{(0.33\,\cancel{mol})(0.0821\frac{atm\cdot \cancel{L}}{\cancel{mol \cdot K}})(248.15\,\cancel{K})}{15.0\,\cancel{L}} = 0.4482\,atmP=
V
nRT
=
15.0
L
(0.33
mol
)(0.0821
mol⋅K
atm⋅
L
)(248.15
K
)
=0.4482atm
In conclusion, the pressure of this gas is P=0.4482 atm.
Reference:
Chang, R. (2010). Chemistry. McGraw-Hill, New York.
Answer:
Explanation:
1. A measure of how quickly velocity is changing is the acceleration
Acceleration is the rate of change of velocity with time. The rate at which a body is changing its velocity is known as the acceleration.
It is measured in the unit m/s²
2. Speed in a given direction is the velocity
Velocity is a vector quantity which measures the magnitude of motion in a specific direction. It is simply speed in a given direction.
When we say a motorcycle travels at the rate of 5m/s due east, we are describing the velocity of such body.
3. Force that resists moving one object against another is the friction
Friction is a force that opposes motion. It prevents a body from moving.
4. Measure of the pull of gravity on an object Weight
Weight is a measure of the amount of gravitational force on a body. It is mathematically expressed as;
W = mg
W is the weight, m is the mass and g is the acceleration due to gravity
5 Tendency of an object to resist a change in motion is inertia
Inertia is the tendency of body to resist change in motion. It is the ability of a body to remain in a perpetual state of rest.
6 Size is the magnitude
Answer:
Explanation:
Firstly, it should be noted that melting and freezing points are the same. Thus, when a substance melts at a certain temperature, it means it can also start freezing/solidifying at that same temperature. That been said, <u>when the substance P is a solid at a certain temperature, the other compound Q will boil at that same temperature and hence will be a gas at that same temperature</u>.
