Answer: molecules
Explanation:
To calculate the moles, we use the equation:
For
Given mass= 165 g
Molar mass of = 44 g/mol
Putting values in above equation, we get:
According to avogadro's law, 1 mole of every substance weighs equal to the molecular mass and contains avogadro's number of particles.
1 mole of contains =
molecules of
Thus 3.75 moles contains =
molecules of
Thus there will be molecules of
The molar mass of CO2 is 44 grams per mole.
165 grams / 44 grams per mole of CO2 = 3.75 moles CO2
Using Avogadro’s law where 1 mole of substance equals 6.023 x 10^23 molecules
3.75 moles CO2 (6.023 x 10^23 molecules /mole) = 2.26 x 10^24 molecules CO2
cesium (Cs)
magnesium (Mg)
titanium (Ti)
Answer: Potassium is the element which is less reactive than rubidium and more reactive than Calcium.
Explanation: Reactivity of an metal is defined as the tendency to loose electrons easily. In a periodic table, the reactivity increases down the group as size of the metal increases. The reactivity decreases across a period as the size of the metal decreases.
Rubidium lies in group 1, which has elements in the series: H, Li, Na, K, Rb, Cs and Fr.
And Calcium lies in period 4 which has elements in the series: K, Ca, (1st transition series), Ga, Ge, As, Se, Br and Kr.
So, the element to have reactivity more than rubidium and less than Calcium must be Potassium (K).
Answer:
A is the correct answer on edge
Explanation:
A)potassium (K)
The common uses of base if for the formation of salts in a neutralisation reaction.
Neutralisation reaction is a type of chemical reaction whereby salt and water is formed from the reaction of an acid and a base.
For example the reaction between NaOH and HCl leads to the formation of a salt called NaCl.
Therefore, the common uses of base if for the formation of salts in a neutralisation reaction.
Learn more about neutralisation reaction here:
#SPJ5
Answer:
6 is B, 7 is A
Explanation:
b. 56.00 s ( a time measured by a stopwatch)
c. 4 choices ( the number of choices in this list)
d. 3 lbs ( the weight of an object measured on a scale )
Answer: a. 2.54 cm ( the number of centimeters in exactly 1 in) and c. 4 choices ( the number of choices in this list)
Justification:
1) a. 2.54 cm ( the number of centimeters in exactly 1 in)
Although the exact length of one inch has varied in the past, currently the inch is defined as exactly 2.54 cm, so this is an exact number.
b. 56.00 s ( a time measured by a stopwatch)
The time measured by a stopwatch is not an exact number. The number is limited by the precision of the instrument (the stopwatch) and it migh have been 56.004 instead of 56.00, and the stopwatch cannot shoe that. So, this is not an exact number.
c. 4 choices ( the number of choices in this list)
This is, indeed an exact number. It is 4, not 4.1, nor 3.9, nor any other number.
d. 3 lbs ( the weight of an object measured on a scale )
As reasoned with the stopwatch, this measure, 3 lbs, is subject to the precision of the scale. It is not an exact number. It could be other number close to 3: 2.99 for example.
These are exact numbers: c. 4 choices ( the number of choices in this list) and d. 3 lbs ( the weight of an object measured on a scale )
The exact number is a value that is known with complete certainty. Examples are counted numbers of objects or certain unit conversions such as exactly 3 feet in 1 yard. Another example is, a dozen is defined as 12 objects, and a pound is defined as 16 ounces.
Fraction an exact number is a fraction takes two integers and places them in a ratio, for example 3/4 or 10/15. A decimal can express the same numerical quantity, but it does so with a single number (like 0.75 or 0.66). So, the fraction makes the relationship among numbers clear in the way it is written.
While a decimal can express the same numerical quantity, but it does so with a single number (like 0.75 or 0.66).
a. 2.54 cm ( the number of centimeters in exactly 1 in) is decimal
b. 56.00 s ( a time measured by a stopwatch) is not exact numbers
c. 4 choices ( the number of choices in this list) is exact numbers
d. 3 lbs ( the weight of an object measured on a scale ) is exact numbers
Grade: 9
Subject: chemistry
Chapter: exact number
Keywords: exact number