Yes this is true as in cold conditions our body doesn't feel the urge of water therefore we may become dehydrated not even knowing about it and of course in hot coditions we sweat therefore we loose water.
Hope this helps :).
Mixtures are made up of 2 or more pure substances. pure substance is just its self and a mixture is multiple substances.
OP already did it - CONGRATS!!
here are the steps 2 get the same ans:
(NH4)2 CO3 has 2x N, 8x H, 1x C and 3x O per molecule
so its molecular mass = 2x14 + 8x1 + 1x12 + 3x16
=28+8+12+48
=96g
of that 96g, 8x1=8g is due to Hydrogen
so by ratio n proportion, 1.00g will have 1x8/96 = 1/12g = 0.083g of H