The correct answer is 2.70 × 10² g or 270 g.
It is given, that the density of a metal is 9.80 g/ml.
Let the mass of a sample of metal be x.
The sample of metal is dropped in 28.9 ml of water, due to which the volume of the water increases to 56.4 ml.
In order to calculate the mass of a metal, there is a need to use the formula, mass = density * volume
Mass = (9.80 g/ml) (56.4 ml - 28.9 ml)
= (9.80 g/ml) (27.5 ml)
= 2.70 × 10² g or 270 g
The amount of heat that could be removed by 20.0 g of ethyl chloride is 8.184 kJ.
<h3>How do we calculate required heat?</h3>
Required amount of heat which can be removed for the vaporization will be calculated as:
Q = (n)(ΔHv), where
- n = moles of ethyl chloride
- ΔHv = heat of vaporization = 26.4 kj/mol
Moles will be calculated as:
n = W/M, where
- W = given mass of ethyl chloride = 20g
- M = molar mass of ethyl chloride = 64.51 g/mol
n = 20 / 64.51 = 0.31 mol
On putting all these values in the above equation, we get
Q = (0.31)(26.4) = 8.184 kJ
Hence involved amount of heat is 8.184 kJ.
To know more about heat of vaporization, visit the below link:
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Answer: The frequency of the green light emitted by a hydrogen atom with a wavelength of 546 nm is 
.
Explanation:
Given: Wavelength = 546 nm 
= 
The relation between frequency and wavelength is as follows.
where,
= frequency
c = speed of light = 
= wavelength
Substitute the values into above formula as follows.
Thus, we can conclude that the frequency of the green light emitted by a hydrogen atom with a wavelength of 546 nm is .
I think is true not sure but it might be
- if the compound is made of just two elements, if one is a metal (ie belongs to any of groups 1, 2 or 3) and the other element a non metal, (ie belongs to group 5, 6 or 7) then the compound is most likely to be an ionic compound. For example NaCl, MgO
- If the compound is made of identical non metalic elements as in O2, Cl2 then the compound is covalent
- If the compoud is made of just two elements that are both non metals such as in SO2, CO, NO, CCl4, the compound is covalent
- If the compound is made up of more than two elements, such as in HNO3, Na2CO3, CuSO4.5H2O, you may need to break the compound into dissociating parts. You will see that, the compounds are ionic.
- Hydrocarbons, compounds containing only hydrogen and carbon of varying molecular size are all covalent. Examples are C2H6, C2H4, C2H2
Note that there could be some little exceptions to the examples given. Mostly with first members of every group because of their small size which make them show substantial deviations from group behavior. For example HCl is covalent not ionic.
