Answer:
The number of valence electrons increases from left to right.
Explanation: The number of valence electrons increases going across a period, or row in the periodic table, for example, group 1 elements have 1 valence electrons and group 2 elements have have 2.
The mass of the hydrogen is obtained as 0.302 g.
<h3>What is the mass of hydrogen?</h3>
A hydrocarbon is a compound that contains only carbon an hydrogen. The amount of the carbon and the hydrogen can be found by combustion.
The mass of hydrogen can be obtained as follows;
Number of moles of hydrogen =2.7 g/18 g/mol * 2 = 0.302 moles
Now the mass of hydrogen is obtained from;
0.302 moles * 1 g/mol = 0.302 g
Learn more about combustion of a compound:brainly.com/question/14272505
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Answer:
Good predictions and warnings save lives.
Explanation:
Predictions and warnings can also reduce damage and economic losses.
Answer:
The time taken for the reaction to go to completion(time taken for the cross to disappear) decreases steadily down the column for time.
Explanation:
If we look at the table closely we would quickly observe the following;
1) the volume of HCl was held constant
2) the volume of sodium thiosulphate was increased steadily
3) the volume of water was decreased steadily
The increase in volume of thiosulphate and decrease in the volume of water meant that reactant concentration was increased steadily. From our knowledge of factors that affect the rate of reaction, we know that the rate of reaction (typically read off as time taken for a given reaction to go to completion, in this case, decrease in the time taken for the cross to disappear) increases with increase in concentration of reactants.
Hence it is expected that as the concentration of reactants increase, the rate of reaction increases. As the rate of reaction increases, the time taken for the cross to disappear decreases. Hence the answer above.
It is C. An increase of temperature results in an increase in kinetic energy of the molecules of the substance. For example, in a gas the molecules will move about faster.